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  • 1.
    Antila, Liisa J.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ghamgosar, Pedram
    Maji, Somnath
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Dynamics and Photochemical H-2 Evolution of Dye-NiO Photocathodes with a Biomimetic FeFe-Catalyst2016In: ACS ENERGY LETTERS, ISSN 2380-8195, Vol. 1, no 6, p. 1106-1111Article in journal (Refereed)
    Abstract [en]

    Mesoporous NiO films were cosensitized with a coumarin 343 dye and a proton reduction catalyst of the [Fe-2(CO)(6)(bdt)] (bdt = benzene-1,2-dithiolate) family. Femtosecond ultraviolet visible transient absorption experiments directly demonstrated subpicosecond hole injection into NiO from excited dyes followed by rapid (t(50%) similar to 6 ps) reduction of the catalyst on the surface with similar to 70% yield. The reduced catalyst was long-lived (2 mu s to 20 ms), which may allow protonation and a second reduction step of the catalyst to occur. A photo electrochemical device based on this photocathode produced H-2 with a Faradaic efficiency of similar to 50%. Fourier transform infrared spectroscopy and gas chromatography experiments demonstrated that the observed device deterioration with time was mainly due to catalyst degradation and desorption from the NiO surface. The insights gained from these mechanistic studies, regarding development of dye-catalyst cosensitized photocathodes, are discussed.

  • 2.
    Besharat, Z.
    et al.
    KTH Royal Inst Technol, Dept Chem, Div Surface & Corros Sci, S-10044 Stockholm, Sweden.;KTH Royal Inst Technol, Mat Phys, ICT, S-16440 Stockholm, Sweden..
    Alvarez-Asencio, R.
    KTH Royal Inst Technol, Dept Chem, Div Surface & Corros Sci, S-10044 Stockholm, Sweden.;IMDEA Nanociencia, Inst Adv Studies, Faraday 9,Campus Cantoblanco, Madrid 28049, Spain..
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Yu, S.
    KTH Royal Inst Technol, Dept Chem Fiber & Polymer Technol, S-10044 Stockholm, Sweden..
    Johnson, C. M.
    KTH Royal Inst Technol, Dept Chem, Div Surface & Corros Sci, S-10044 Stockholm, Sweden..
    Gothelid, M.
    KTH Royal Inst Technol, Mat Phys, ICT, S-16440 Stockholm, Sweden..
    Rutland, M. W.
    KTH Royal Inst Technol, Dept Chem, Div Surface & Corros Sci, S-10044 Stockholm, Sweden..
    In-situ evaluation of dye adsorption on TiO2 using QCM2017In: EPJ Photovoltaics, ISSN 2105-0716, Vol. 8, article id 80401Article in journal (Refereed)
    Abstract [en]

    We measured the adsorption characteristics of two organic dyes; triphenylamine-cyanoacrylic acid (TPA-C) and phenoxazine (MP13), on TiO2, directly in a solution based on quartz crystal microbalance (QCM). Monitoring the adsorbed amount as a function of dye concentration and during rinsing allows determination of the equilibrium constant and distinction between chemisorbed and physisorbed dye. The measured equilibrium constants are 0.8 mM(-1) for TPA-C and 2.4 mM(-1) for MP13. X-ray photoelectron spectroscopy was used to compare dried chemisorbed layers of TPA-C prepared in solution with TPA-C layers prepared via vacuum sublimation; the two preparation methods render similar spectra except a small contribution of water residues (OH) on the solution prepared samples. Quantitative Nanomechanical Mapping Atomic Force Microscopy (QNM-AFM) shows that physisorbed TPA-C layers are easily removed by scanning the tip across the surface. Although not obvious in height images, adhesion images clearly demonstrate removal of the dye.

  • 3. Chen, Ruikui
    et al.
    Yang, Xichuan
    Tian, Haining
    Sun, Licheng.
    Tetrahydroquinoline dyes with different spacers for organic dye-sensitized solar cells.2007In: Journal of Photochemistry and Photobiology A: Chemistry, ISSN 1010-6030, E-ISSN 1873-2666, Vol. 189, no 2-3, p. 295-300Article in journal (Refereed)
    Abstract [en]

    Novel org. dyes (C1-1, C1-5 and C2-1) with a tetrahydroquinoline moiety as the electron donor, different thiophene-contg. electron spacers and a cyanoacrylic acid moiety as the electron acceptor have been designed and synthesized for the application in dye-sensitized solar cells (DSSCs). An interesting relationship between the dye structures, properties, and the performance of DSSCs based on these tetrahydroquinoline dyes is obtained. Although C2-1 dye, which has a rigid electron spacer, has the narrowest action spectrum among these dyes, it gives the highest solar-to-electricity conversion efficiency (η) of 4.49% (Voc = 600 mV, Jsc = 11.20 mA/cm2, ff = 0.67) of a DSSC under simulated AM 1.5 irradn. (100 mW/cm2). Under the same conditions, the η value of a DSSC based on N3 dye is 6.16%. [on SciFinder(R)]

  • 4. Chen, Ruikui
    et al.
    Yang, Xichuan
    Tian, Haining
    Wang, Xiuna
    Hagfeldt, Anders
    Sun, Licheng.
    Effect of Tetrahydroquinoline Dyes Structure on the Performance of Organic Dye-Sensitized Solar Cells.2007In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 19, no 16, p. 4007-4015Article in journal (Refereed)
    Abstract [en]

    Eleven novel donor acceptor π-conjugated (D-π-A) org. dyes were engineered and synthesized as sensitizers for the application in dye-sensitized solar cells (DSSCs). The electron-donating moieties are substituted tetrahydroquinoline, and the electron-withdrawing parts are cyanoacrylic acid group or cyanovinylphosphonic acid group. Different lengths of thiophene-contg. conjugation moieties (thienyl, thienylvinyl, and dithieno[3,2-b;2',3'-d]thienyl) are introduced to the mols. and serve as electron spacers. Detailed study on the relation between the dye structure, photophys. and photoelectrochem. properties, and performance of DSSCs is described here. The bathochromic shift and increase of the molar absorptivity of the absorption spectrum are achieved by introduction of larger conjugation moiety. Even small structural changes of dyes result in significant changes in redox energies and adsorption manner of the dyes on TiO2 surface, affecting dramatically the performance of DSSCs based on these dyes. The higher performances are obtained by DSSCs based on the rigid dye mols., C2 series dyes (Figure 1), although these dyes have lower light absorption abilities relative to other dyes. A max. solar-to-elec. energy conversion efficiency (η) of 4.53% is achieved under simulated AM 1.5 irradn. (100 mW/cm2) with a DSSC based on C2-2 dye (Voc = 597 mV, Jsc = 12.00 mA/cm2, ff = 0.63). D. functional theory (DFT) calcns. were performed on the dyes, and electron distribution from the whole mols. to the anchoring moieties occurred during the HOMO-LUMO excitation. The cyanoacrylic acid groups or cyanovinylphosphonic acid group are essentially coplanar with respect to the thiophene units, reflecting the strong conjugation across the thiophene-anchoring groups. [on SciFinder(R)]

  • 5. Chen, Ruikui
    et al.
    Zhao, Guangjiu
    Yang, Xichuan
    Jiang, Xiao
    Liu, Jifeng
    Tian, Haining
    Gao, Yan
    Liu, Xien
    Han, Keli
    Sun, Mengtao
    Sun, Licheng.
    Photoinduced intramolecular charge-transfer state in thiophene-π-conjugated donor-acceptor molecules.2008In: Journal of Molecular Structure, ISSN 0022-2860, E-ISSN 1872-8014, Vol. 876, no 1-3, p. 102-109Article in journal (Refereed)
    Abstract [en]

    Novel thiophene-π-conjugated donor-acceptor mols., 5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thiophene-2-carbaldehyde (QTC) and (1-cyano-2-{5-[2-(1,2,2,4-tetramethyl-1,2,3,4-tetrahydroquinolin-6-yl)-vinyl]-thiophen-2-yl}-vinyl)-phosphonic acid di-Et ester (QTCP), were designed and synthesized. Combined exptl. and theor. methods were performed to investigate the photoinduced intramol. charge-transfer (ICT) processes of these compds. Steady-state absorption and fluorescence measurements in different solvents indicate the photoinduced ICT characters of QTC and QTCP. Solvent dependency of the large Stokes shifts and high dipole moment of the excited state also support the charge-transfer character of the excited state. Theor. calcns. based on time-dependent d. functional theory (TDDFT) method were performed to investigate ICT states of these compds. The results reveal that the excited states have adopted a distortion of the C=C double bond between the donor moiety and the thiophene-π-bridge. [on SciFinder(R)]

  • 6.
    Chen, Yun
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Chen, Hong
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Immobilization of a cobalt catalyst on fullerene in molecular devices for water reduction2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 57, p. 11508-11511Article in journal (Refereed)
    Abstract [en]

    A cobalt-based molecular catalyst was successfully grafted to a fullerene derivative via 'click' chemistry on an electrode for both electro-catalytic and light driven water reduction. Using an organic photovoltaic electrode immobilized with a cobalt catalyst as the photocathode, the photoelectrochemical cell displayed a stable photocurrent.

  • 7.
    D'Amario, Luca
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Jiang, Roger
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Cappel, Ute B.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Gibson, Elizabeth A.
    Newcastle Univ, Sch Chem, Newcastle Upon Tyne NE1 7RU, Tyne & Wear, England.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Royal Inst Technol KTH, Ctr Mol Devices, Dept Chem, S-10044 Stockholm, Sweden.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Sun, Licheng
    Royal Inst Technol KTH, Ctr Mol Devices, Dept Chem, S-10044 Stockholm, Sweden.; Organ Chem Royal Inst Technol KTH, Dept Chem, S-10044 Stockholm, Sweden..
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Royal Inst Technol KTH, Ctr Mol Devices, Dept Chem, S-10044 Stockholm, Sweden.
    Chemical and Physical Reduction of High Valence Ni States in Mesoporous NiO Film for Solar Cell Application.2017In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 9, no 39, p. 33470-33477Article in journal (Refereed)
    Abstract [en]

    The most common material for dye-sensitized photocathodes is mesoporous NiO. We transformed the usual brownish NiO to be more transparent by reducing high valence Ni impurities. Two pretreatment methods have been used: chemical reduction by NaBH4 and thermal reduction by heating. The power conversion efficiency of the cell was increased by 33% through chemical treatment, and an increase in open-circuit voltage from 105 to 225 mV was obtained upon heat treatment. By optical spectroelectrochemistry, we could identify two species with characteristically different spectra assigned to Ni3+ and Ni4+. We suggest that the reduction of surface Ni3+ and Ni4+ to Ni2+ decreases the recombination reaction between holes on the NiO surface with the electrolyte. It also keeps the dye firmly on the surface, building a barrier for electrolyte recombination. This causes an increase in open-circuit photovoltage for the treated film.

  • 8. Gabrielsson, Erik
    et al.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Eriksson, Susanna K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Gao, Jiajia
    Chen, Hong
    Li, Fusheng
    Oscarsson, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Sun, Junliang
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Kloo, Lars
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Sun, Licheng
    Dipicolinic acid: a strong anchoring group with tunable redox and spectral behavior for stable dye-sensitized solar cells2015In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, no 18, p. 3858-3861Article in journal (Refereed)
    Abstract [en]

    Dipicolinic acidwas investigated as a new anchoring group for DSSCs. A pilot dye (PD2) bearing this new anchoring group was found to adsorb significantly stronger to TiO2 than its cyanoacrylic acid analogue. The electrolyte composition was found to have a strong effect on the photoelectrochemical properties of the adsorbed dye in the device, allowing the dye LUMO energy to be tuned by 0.5 eV. Using a pyridine-free electrolyte, panchromatic absorption of the dye on TiO2 extending to 900 nm has been achieved. Solar cells using PD2 and a Co(bpy)(3) based electrolyte showed unique stability under simulated sunlight and elevated temperatures.

  • 9.
    Gilbert Gatty, Mélina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Pullen, Sonja
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Sheibani, E.
    Royal Inst Technol, Dept Chem Chem Sci & Engn, KTH, Organ Chem, S-10044 Stockholm, Sweden;Univ Ishafan, Dept Chem, Ishafan 8174673441, Iran.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ott, Sascha
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Direct evidence of catalyst reduction on dye and catalyst co-sensitized NiO photocathodes by mid-infrared transient absorption spectroscopy2018In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 9, no 22, p. 4983-4991Article in journal (Refereed)
    Abstract [en]

    Co-sensitization of molecular dyes and catalysts on semiconductor surfaces is a promising strategy to build photoelectrodes for solar fuel production. In such a photoelectrode, understanding the charge transfer reactions between the molecular dye, catalyst and semiconductor material is key to guide further improvement of their photocatalytic performance. Herein, femtosecond mid-infrared transient absorption spectroscopy is used, for the first time, to probe charge transfer reactions leading to catalyst reduction on co-sensitized nickel oxide (NiO) photocathodes. The NiO films were co-sensitized with a molecular dye and a proton reducing catalyst from the family of [FeFe](bdt)(CO)(6) (bdt = benzene-1,2-dithiolate) complexes. Two dyes were used: an organic push-pull dye denoted E2 with a triarylamine-oligothiophene-dicyanovinyl structure and a coumarin 343 dye. Upon photo-excitation of the dye, a clear spectroscopic signature of the reduced catalyst is observed a few picoseconds after excitation in all co-sensitized NiO films. However, kinetic analysis of the transient absorption signals of the dye and reduced catalyst reveal important mechanistic differences in the first reduction of the catalyst depending on the co-sensitized molecular dye (E2 or C343). While catalyst reduction is preceded by hole injection in NiO in C343-sensitized NiO films, the singly reduced catalyst is formed by direct electron transfer from the excited dye E2* to the catalyst in E2-sensitized NiO films. This change in mechanism also impacts the lifetime of the reduced catalyst, which is only ca. 50 ps in E2-sensitized NiO films but is >5 ns in C343-sensitized NiO films. Finally, the implication of this mechanistic study for the development of better co-sensitized photocathodes is discussed.

  • 10.
    Hao, Yan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Cong, Jiayan
    Yang, Wenxing
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Bora, Ilkay
    Sun, Licheng
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Triphenylamine Groups Improve Blocking Behavior of Phenoxazine Dyes in Cobalt-Electrolyte-Based Dye-Sensitized Solar Cells2014In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 15, no 16, p. 3476-3483Article in journal (Refereed)
    Abstract [en]

    Novel phenoxazine dyes are successfully introduced as sensitizers into dye-sensitized solar cells (DSCs) with cobalt-based electrolyte. In sensitizers with triphenylamine (TPA) groups recombination from electrons in the TiO2 conduction band to the cobalt(III) species is suppressed. The effect of the steric properties of the phenoxazine sensitizers on the overall device performance and on recombination and regeneration processes is compared. Optimized DSCs sensitized with IB2 having two TPA groups in combination with tris(2,2'-bipyridyl) cobalt( II/III) yield efficiencies of 6.3 %, similar to that of IB3, which is equipped with mutiple alkoxy groups. TH310 with only one TPA group gives lower efficiency and open circuit voltage, while IB1 without TPA groups performs even worse. These results demonstrate that both TPA groups on the IB2 are needed for an efficient blocking effect. These results reveal a possible new role for TPA units in DSC sensitizer design.

  • 11. Hao, Yan
    et al.
    Yang, Xichuan
    Cong, Jiayan
    Tian, Haining
    Hagfeldt, Anders
    Sun, Licheng.
    Efficient near infrared D-π-A sensitizers with lateral anchoring group for dye-sensitized solar cells.2009In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 27, p. 4031-4033Article in journal (Refereed)
    Abstract [en]

    A new strategy in which the anchoring group is sepd. from the acceptor groups of the dyes was developed; among these dyes, the HY103 dye gives a max. IPCE value of 86% at 660 nm and an η value of 3.7% in the NIR region reported in DSCs. [on SciFinder(R)]

  • 12.
    Hua, Yong
    et al.
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Organ Chem,Ctr Mol Devices, Teknikringen 30, SE-10044 Stockholm, Sweden..
    Xu, Bo
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Organ Chem,Ctr Mol Devices, Teknikringen 30, SE-10044 Stockholm, Sweden..
    Liu, Peng
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Appl Phys Chem, Teknikringen 30, SE-10044 Stockholm, Sweden..
    Chen, Hong
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Organ Chem,Ctr Mol Devices, Teknikringen 30, SE-10044 Stockholm, Sweden..
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Cheng, Ming
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Organ Chem,Ctr Mol Devices, Teknikringen 30, SE-10044 Stockholm, Sweden..
    Kloo, Lars
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Appl Phys Chem, Teknikringen 30, SE-10044 Stockholm, Sweden..
    Sun, Licheng
    KTH Royal Inst Technol, Sch Chem Sci & Engn, Dept Chem, Organ Chem,Ctr Mol Devices, Teknikringen 30, SE-10044 Stockholm, Sweden.;Dalian Univ Technol, DUT KTH Joint Res Ctr Mol Devices, State Key Lab Fine Chem, Dalian 116024, Peoples R China..
    High conductivity Ag-based metal organic complexes as dopant-free hole-transport materials for perovskite solar cells with high fill factors2016In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 7, no 4, p. 2633-2638Article in journal (Refereed)
    Abstract [en]

    Hole-transport materials (HTMs) play an important role as hole scavenger materials in the most efficient perovskite solar cells (PSCs). Here, for the first time, two Ag-based metal organic complexes (HA1 and HA2) are employed as a new class of dopant-free hole-transport material for application in PSCs. These HTMs show excellent conductivity and hole-transport mobility. Consequently, the devices based on these two HTMs exhibit unusually high fill factors of 0.76 for HA1 and 0.78 for HA2, which are significantly higher than that obtained using spiro-OMeTAD (0.69). The cell based on HA1-HTM in its pristine form achieved a high power conversion efficiency of 11.98% under air conditions, which is comparable to the PCE of the cell employing the well-known doped spiro-MeOTAD (12.27%) under the same conditions. More importantly, their facile synthesis and purification without using column chromatography makes these new silver-based HTMs highly promising for future commercial applications of PSCs. These results provide a new way to develop more low-cost and high conductivity metal-complex based HTMs for efficient PSCs.

  • 13.
    Huang, Jing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Gilbert Gatty, Mélina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Xu, Bo
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Pati, Palas Baran
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Etman, Ahmed S.
    Stockholm Univ, Dept Mat & Environm Chem MMK, SE-10691 Stockholm, Sweden.
    Tian, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Sun, Junliang
    Stockholm Univ, Dept Mat & Environm Chem MMK, SE-10691 Stockholm, Sweden.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Covalently linking CuInS2 quantum dots with a Re catalyst by click reaction for photocatalytic CO2 reduction2018In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 31, p. 10775-10783Article in journal (Refereed)
    Abstract [en]

    Covalently linking photosensitizers and catalysts in an inorganic-organic hybrid photocatalytic system is beneficial for efficient electron transfer between these components. However, general and straightforward methods to covalently attach molecular catalysts on the surface of inorganic semiconductors are rare. In this work, a classic rhenium bipyridine complex (Re catalyst) has been successfully covalently linked to the low toxicity CuInS2 quantum dots (QDs) by click reaction for photocatalytic CO2 reduction. Covalent bonding between the CuInS2 QDs and the Re catalyst in the QD-Re hybrid system is confirmed by UV-visible absorption spectroscopy, Fourier-transform infrared spectroscopy and energy-dispersive X-ray measurements. Time-correlated single photon counting and ultrafast time-resolved infrared spectroscopy provide evidence for rapid photo-induced electron transfer from the QDs to the Re catalyst. Upon photo-excitation of the QDs, the singly reduced Re catalyst is formed within 300 fs. Notably, the amount of reduced Re in the linked hybrid system is more than that in a sample where the QDs and the Re catalyst are simply mixed, suggesting that the covalent linkage between the CuInS2 QDs and the Re catalyst indeed facilitates electron transfer from the QDs to the Re catalyst. Such an ultrafast electron transfer in the covalently linked CuInS2 QD-Re hybrid system leads to enhanced photocatalytic activity for CO2 reduction, as compared to the conventional mixture of the QDs and the Re catalyst.

  • 14.
    Huang, Jing
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. KTH Royal Inst Technol, Sch Engn Sci, Dept Appl Phys, Stockholm, Sweden.
    Xu, Bo
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Pati, Palas Baran
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Etman, Ahmed S.
    Stockholm Univ, Dept Mat & Environm Chem MMK, SE-10691 Stockholm, Sweden.
    Sun, Junliang
    Stockholm Univ, Dept Mat & Environm Chem MMK, SE-10691 Stockholm, Sweden.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    A heavy metal-free CuInS2 quantum dot sensitized NiO photocathode with a Re molecular catalyst for photoelectrochemical CO2 reduction2019In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 55, no 55, p. 7918-7921Article in journal (Refereed)
    Abstract [en]

    Heavy metal-free CuInS2 quantum dots (QDs) were employed as a photosensitizer on a NiO photocathode to drive an immobilized molecular Re catalyst for photoelectrochemical CO2 reduction for the first time. A photocurrent of 25 mu A cm(-2) at -0.87 V vs. NHE was obtained, providing a faradaic efficiency of 32% for CO production.

  • 15.
    Imani, Roghayeh
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Qiu, Zhen
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Younesi, Reza
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Pazoki, Meysam
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry. Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Fernandes, Daniel L. A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Mitev, Pavlin D.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Structural Chemistry.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Unravelling in-situ formation of highly active mixed metal oxide CuInO2 nanoparticles during CO2 electroreduction2018In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 49, p. 40-50Article in journal (Refereed)
    Abstract [en]

    Technologies and catalysts for converting carbon dioxide (CO2) to immobile products are of high interest to minimize greenhouse effects. Copper(I) is a promising catalytic active state of copper but hampered by the inherent instability in comparison to copper(II) or copper(0). Here, we report a stabilization of the catalytic active state of copper(I) by the formation of a mixed metal oxide CuInO2 nanoparticle during the CO2 electroreduction. Our result shows the incorporation of nanoporous Sn:In2O3 interlayer to Cu2O pre-catalyst system lead to the formation of CuInO2 nanoparticles with remarkably higher activity for CO2 electroreduction at lower overpotential in comparison to the conventional Cu nanoparticles derived from sole Cu2O. Operando Raman spectroelectrochemistry is employed to in-situ monitor the process of nanoparticles formation during the electrocatalytic process. The experimental data are collaborated with DFT calculations to provide insight into the electro-formation of the type of Cu-based mixed metal oxide catalyst during the CO2 electroreduction, where a formation mechanism via copper ion diffusion across the substrate is suggested.

  • 16. Li, Chaoyan
    et al.
    Yang, Xichuan
    Chen, Ruikui
    Pan, Jingxi
    Tian, Haining
    Zhu, Hongjun
    Wang, Xiuna
    Hagfeldt, Anders
    Sun, Licheng.
    Anthraquinone dyes as photosensitizers for dye-sensitized solar cells.2007In: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 91, no 19, p. 1863-1871Article in journal (Refereed)
    Abstract [en]

    Three anthraquinone dyes with carboxylic acid as anchoring group are designed and synthesized as sensitizers for dye-sensitized solar cells (DSSCs). Preliminary photophys. and photoelectrochem. measurements show that these anthraquinone dyes have very low performance on DSSC applications, although they have broad and intense absorption spectra in the visible region (up to 800 nm). Transient absorption kinetics, fluorescence lifetime measurements and d. functional theory (DFT) calcns. are conducted to investigate the cause of such low DSSC performance for these dyes. The strong electron-withdrawing character of the two carbonyl groups on anthraquinone framework may lie behind the low performance by suppressing the efficient electron injection from the dye to the conduction band of TiO2. [on SciFinder(R)]

  • 17. Li, Ling
    et al.
    Hao, Yan
    Yang, Xichuan
    Zhao, Jianzhang
    Tian, Haining
    Teng, Chao
    Hagfeldt, Anders
    Sun, Licheng.
    A Double-Band Tandem Organic Dye-sensitized Solar Cell with an Efficiency of 11.5 %.2011In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 4, no 5, p. 609-612Article in journal (Refereed)
    Abstract [en]

    The absorption spectra of most org. dyes reported thus far used for mesoporous nanostructured dye-sensitized solar cells mainly cover the visible-light region. This has motivated research towards the development of new types of org. dyes(7-10) with absorption spectra extended to the near-IR and IR region. By adjusting the donor, linker, and acceptor units, this group developed a tandem Dye-sensitized Solar Cell in which the front subcell employs a ZrO2-doped nanostructured TiO2 semiconductor to improve the photovoltage and an org. 3-[2-(N,N-diphenylamino)-ethenyl]-phenoxazinyl-cyanoacrylic acid dye (TH305) to harvest sunlight in the 400-750 nm region, giving an efficiency of 9.05 % with a high photovoltage (794 mV), while the back subcell employs a normal TiO2 electrode sensitized with a different org. dye (HY103) to capture sunlight in the 500-800 nm region, achieving an addnl. efficiency of 2.45 %. The two sub-cells are sepd. by a double-sided fluoride-doped tin oxide conducting glass. Shifting the CB band of TiO2towards more neg. values is an effective way to improve the open-circuit photovoltage (Voc) and increase the DSC's efficiency. The two methods used to make the CB more neg. are : (a) adding an org. base, 4-tert-butylpyridine, to the electrolyte, and (b) doping the TiO2 with semiconductor materials with a more-neg. CB energy level (EcB), ZrO2, which has a wider band gap (ca. 5.0 eV) and a more-neg. CB level (-1.0 V vs. normal hydrogen electrode). The org. dye TH305 was chosen for the front subcell because its more neg. LUMO level (-1.28V vs. NHE) matches the ECB of ZrO2-doped TiO2. Undoped titania was used for the second sub-cell. The total conversion efficiency was 9.05%, with a Voc of 0.794V, and a Jsc of 15/20 mA/cm2. [on SciFinder(R)]

  • 18. Li, Ling
    et al.
    Yang, Xichuan
    Gao, Jiajia
    Tian, Haining
    Zhao, Jianzhang
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Sun, Licheng
    Highly Efficient CdS Quantum Dot-Sensitized Solar Cells Based on a Modified Polysulfide Electrolyte2011In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 133, no 22, p. 8458-8460Article in journal (Refereed)
    Abstract [en]

    A modified polysulfide redox couple, [(CH3)(4)N](2)S/[(CH3)(4)N](2)S-n, in an organic solvent (3-methoxypropionitrile) was employed in CdS quantum dot (QD)-sensitized solar cells (QDSSCs), and an unprecedented energy conversion efficiency of up to 3.2% was obtained under AM 1.5 G illumination. The QDs were linked to nanoporous TiO2 via covalent bonds by using thioglycolic acid, and chemical bath deposition in an organic solvent was then used to prepare the QDSSCs, facilitating high wettability and superior penetration capability of the TiO2 films. A very high fill factor of 0.89 was observed with the optimized QDSSCs.

  • 19.
    Liu, Aijie
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tai, Cheuk-Wai
    Stockholm Univ, Arrhenius Lab, Dept Mat & Environm Chem, SE-10691 Stockholm, Sweden.
    Hola, Katerina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hollow polymer dots: nature-mimicking architecture for efficient photocatalytic hydrogen evolution reaction2019In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 9, p. 4797-4803Article in journal (Refereed)
    Abstract [en]

    Mimicking nature is always beneficial for improving the performance of artificial systems. Artificial photosynthesis for hydrogen production is one of the examples, where we can derive significant inspiration from nature. In this study, polymer dots (Pdots) prepared using photoactive polymer PFODTBT and amphiphilic co-polymer under ultra-sonication exhibited a hollow structure mimicking a photosynthetic bacterial, which was highly beneficial for hydrogen evolution. A systematic study of this structure showed that the polymer shell acts as a biological membrane that maintains a slightly higher pH inside the cavity (pH 0.4) compared to the bulk solution. More importantly, a fast proton diffusion across the porous polymer shell was detected. The photocatalytic activity of hollow nanostructure shows 50 times enhancement of initial hydrogen evolution reaction (HER) rate as compared to solid nanoparticles. Further optimization of the photocatalytic performance was achieved by verifying the decrease in Pdots size from 90 nm to 50 nm, showing a significant increase in the photocatalytic performance of the system. This study reveals nature-mimicking hollow Pdots with porous shells as can be a type of promising photocatalysts in the application of solar energy conversion and storage.

  • 20. Ning, Zhijun
    et al.
    Tian, Haining
    Qin, Haiyan
    Zhang, Qiong
    Aagren, Hans
    Sun, Licheng
    Fu, Ying.
    Wave-Function Engineering of CdSe/CdS Core/Shell Quantum Dots for Enhanced Electron Transfer to a TiO2 Substrate.2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 35, p. 15184-15189Article in journal (Refereed)
    Abstract [en]

    The authors synthesized core/shell quantum dots (QDs) for the purpose of enhancing the electron transfer from the dots to a TiO2 substrate. The authors make use of the fact that CdSe is a small-bandgap material compared with CdS; therefore, in a common CdSe/CdS core/shell QD, the photoexcited electron is confined deeply in the CdSe core. By special construction of the CdS/CdSe core/shell QDs, referred as reversed type-I, the electron wave function will distribute largely in the shell region. This facilitates the transfer of the electron from the QD to the TiO2 substrate, resulting in significantly improved electron-injection efficiency. Such an enhanced electron-injection efficiency was confirmed by fluorescence lifetime decay measurements, showing the largest lifetime redn. after that the QDs were adsorbed on the TiO2 surface. The reversed type-I CdS/CdSe QDs show a much higher photon-to-current conversion efficiency than type-I CdSe/CdS and CdSe QDs without shell. Also, by chem.-bath depositing of CdS on the QD-sensitized electrode to form a quantum-well structure, the electron recombination between the QDs and the redox couple was reduced, hence further enhancing the electron-injection efficiency. The absorbed-photon-to-current efficiency of the quantum well CdS/CdSe/CdS sensitized solar cells reaches a value ≤60%. [on SciFinder(R)]

  • 21. Ning, Zhijun
    et al.
    Tian, Haining
    Yuan, Chunze
    Fu, Ying
    Qin, Haiyan
    Sun, Licheng
    Aagren, Hans.
    Solar cells sensitized with type-II ZnSe-CdS core/shell colloidal quantum dots.2011In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, no 5, p. 1536-1538Article in journal (Refereed)
    Abstract [en]

    Type-II quantum dots (QDs) were applied for QDs-sensitized solar cells and showed prominent absorbed photon-to-current conversion efficiency. [on SciFinder(R)]

  • 22. Ning, Zhijun
    et al.
    Tian, Haining
    Yuan, Chunze
    Fu, Ying
    Sun, Licheng
    Aagren, Hans.
    Pure Organic Redox Couple for Quantum-Dot-Sensitized Solar Cells.2011In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 23, p. 6330-6333Article in journal (Refereed)
    Abstract [en]

    The authors introduced a pure org. electrolyte, tetrabutylammonium 5-methyl-2-mercapto-1,3,4-thiazole/2,2'-dithiobis[5-methyl-1,3,4-thiazole] (McMT-/BMT), for Quantum-Dot-Sensitized Solar Cells (QDSCs). The pure org. electrolyte shows an obviously reduced charge recombination compared with previously employed inorg. polysulfide electrolytes, thus the overall conversion efficiency of QDSCs based on the new electrolyte was doubled. This electrolyte also avoids the metal corrosion character of the iodine electrolytes which make it a promising electrolyte candidate for QDSCs. It was found that the charge re-combination was reduced by sintering the QD adsorbed TiO2 film. [on SciFinder(R)]

  • 23. Ning, Zhijun
    et al.
    Yuan, Chunze
    Tian, Haining
    Fu, Ying
    Li, Lin
    Sun, Licheng
    Aagren, Hans.
    Type-II colloidal quantum dot sensitized solar cells with a thiourea based organic redox couple.2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 13, p. 6032-6037Article in journal (Refereed)
    Abstract [en]

    In this paper, one kind of org. electrolyte based on tetramethylthiourea is employed for quantum dot sensitized solar cells (QDSCs). By reducing the impedance between the electrolyte and the counter electrode, the fill factor of such org. electrolyte based QDSCs is significantly improved. It is possible to substantially increase the photovoltage and to reach an efficiency three times higher than that of a commonly used inorg. electrolyte. The light harvesting ability of the org. electrolyte based QDSCs is successfully extended by using type-II QDs, where the adsorption of ZnS gives an addnl. advantage in further enhancing the stability of the cells. It is obsd. that core/shell ZnSe/CdS type-II QDs give higher electron injection than CdS/ZnSe QDs, proving that the electron distribution in the QDs is important for the electron extn. A full working mechanism of the org. redox couple for the QDSCs is proposed. [on SciFinder(R)]

  • 24. Ning, Zhijun
    et al.
    Yuan, Chunze
    Tian, Haining
    Hedstroem, Peter
    Sun, Licheng
    Aagren, Hans.
    Quantum Rod-Sensitized Solar Cells.2011In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 4, no 12, p. 1741-1744Article in journal (Refereed)
    Abstract [en]

    A new type of CdSe nanorod material was prepd. with cadmium sulfide as seed material and the properties of a quantum rod-sensitized titania solar cell were studied. This cell showed better electron injection efficiency than corresponding quantum dot-sensitized solar cells, indicating that electrons can be more easily injected from quantum rods than from quantum dots. We have demonstrated a new strategy to increase the electron injection efficiency of nanocrystal-sensitized solar cells by modification of the shape of the nanocrystals. [on SciFinder(R)]

  • 25.
    Pati, Palas Baran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Damas, Giane
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Tian, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Fernandes, Daniel L. A.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Zhang, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Bayrak Pehlivan, Ilknur
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Edvinsson, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Araujo, Carlos Moyses
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Materials Theory.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    An experimental and theoretical study of an efficient polymer nano-photocatalyst for hydrogen evolution2017In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 10, no 6, p. 1372-1376Article in journal (Refereed)
    Abstract [en]

    In this work, we report a highly efficient organic polymer nano-photocatalyst for light driven proton reduction. The system renders an initial rate of hydrogen evolution up to 50 +/- 0.5 mmol g(-1) h(-1), which is the fastest rate among all other reported organic photocatalysts. We also experimentally and theoretically prove that the nitrogen centre of the benzothiadiazole unit plays a crucial role in the photocatalysis and that the Pdots structure holds a close to ideal geometry to enhance the photocatalysis.

  • 26.
    Pati, Palas Baran
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Zhang, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Philippe, Bertrand
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Fernández-Terán, Ricardo
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ahmadi, Sareh
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Tian, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and Condensed Matter Physics.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices2017In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 10, no 11, p. 2480-2495Article in journal (Refereed)
    Abstract [en]

    A covalently-linked organic dye-cobaloxime catalyst system is developed by facile click reaction for mechanistic studies and application in a dye sensitized solar fuel device based on mesoporous NiO. This system has been systematically investigated by photophysical measurements, density functional theory, time resolved fluorescence, transient absorption spectroscopy as well as photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer to reduce the catalyst unit. Moreover, they suggest that the dye undergoes structural changes in the excited state and that excitation energy transfer occurs between neighboring molecules. The photoelectrochemical experiments also show the hydrogen production by this system-based NiO photocathode. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst on photocathode is eventually proposed on the basis of this study.

  • 27. Sheibani, Esmaeil
    et al.
    Zhang, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Liu, Peng
    Xu, Bo
    Mijangos, Edgar
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Kloo, Lars
    Tian, Haining
    A study of oligothiophene–acceptor dyes in p-type dye-sensitized solar cells2016In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, no 22, p. 18165-18177Article in journal (Refereed)
    Abstract [en]

    Two new dyes, E1 and E2, equipped with triphenylamine as the electron donor, oligothiophene as the linkerand different electron acceptor groups, have been designed and synthesized as photosensitizers for p-typedye-sensitized solar cells (p-DSCs). A systematic study of the effect of molecular structures on the observedphotophysical properties, the electron/hole recombination process, the overall performance and theinterfacial charge separation was carried out. Transient absorption spectroscopy (TAS) shows that the E1dye with a napthoilene-1,2-benzimidazole (NBI) unit as the acceptor has a longer lifetime in the reducedstate than the E2 dye with a malononitrile subunit on the NiO surface.

  • 28.
    Sorcar, Saurav
    et al.
    DGIST, Dept Energy Syst Engn, 50-1 Sang Ri, Daegu 42988, South Korea..
    Razzaq, Abdul
    DGIST, Dept Energy Syst Engn, 50-1 Sang Ri, Daegu 42988, South Korea..
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Grimes, Craig A.
    Flux Photon Corp, 116 Donmoor Court, Garner, NC 27529 USA..
    In, Su-Il
    DGIST, Dept Energy Syst Engn, 50-1 Sang Ri, Daegu 42988, South Korea..
    Facile electrochemical synthesis of anatase nano-architectured titanium dioxide films with reversible superhydrophilic behavior2017In: Journal of Industrial and Engineering Chemistry, ISSN 1226-086X, E-ISSN 1876-794X, Vol. 46, p. 203-211Article in journal (Refereed)
    Abstract [en]

    In the present work we report a facile and readily-scalable electrochemical anodization technique for preparation of superhydrophilic TiO2 films having reversible wettability properties. The electrochemically anodized Titanium (Ti) foils manifest nanoscale topographical features, interconnected nanowebs and nanofibrils, that enhance both surface roughness and light absorption. After 5 min of UV illumination a water contact angle (WCA) of 4.8 degrees is measured for a 5 mu L deionized water droplet, while after 5 min of whitelight illumination the WCA is 3.2 degrees. Moreover, under UV illumination the superhydrophilic Ti foils exhibit self-cleaning properties. Key factors contributing to the superhydrophilic character include surface topology, and surface chemical reactions.

  • 29. Teng, Chao
    et al.
    Yang, Xichuan
    Yang, Chao
    Tian, Haining
    Li, Shifeng
    Wang, Xiuna
    Hagfeldt, Anders
    Sun, Licheng.
    Influence of triple bonds as π-spacer units in metal-free organic dyes for dye-sensitized solar cells.2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 25, p. 11305-11313Article in journal (Refereed)
    Abstract [en]

    Four metal-free org. sensitizers (TC101-TC104) with triple bonds in π-spacers and 5 ref. dyes (TC, TC105, TPC1, D5, and TH208) without triple bonds were applied in dye-sensitized solar cells to study the influence of triple bonds as π-spacer units on their photoelectrochem. properties and dye-sensitized solar cells (DSCs) performance. The introduction of triple bond could red shift the dye's absorption spectrum due to the enhancement of the π-spacer. However, the spectrum red shift is much less than that of the introduction of double bond because of more electronegativity of triple bond. The incident photon-to-current conversion efficiency reveals that the electron transfer yield (Φ(ν)ET) of DSCs becomes larger with the introduction of triple bond. Electrochem. impedance spectroscopy anal. reveals that the introduction of triple bond almost does not change the electron lifetimes in TiO2 films but decreases the effective diffusion lengths. [on SciFinder(R)]

  • 30.
    Teng, Chao
    et al.
    Dalian University of Technology, China.
    Yang, Xichuan
    Dalian University of Technology, China.
    Yang, Chao
    Dalian University of Technology, China.
    Tian, Haining
    Dalian University of Technology, China.
    Li, Shifeng
    Dalian University of Technology, China.
    Wang, Xiuna
    Dalian University of Technology, China.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Sun, Licheng
    Center of Molecular Devices, Physical Chemistry, KTH.
    Influence of Triple Bonds as π-Spacer Units in Metal-Free Organic Dyes for Dye-SensitizedSolar Cells2010In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 114, no 25, p. 11305-11313Article in journal (Refereed)
    Abstract [en]

    Four metal-free organic sensitizers (TC101-TC104) with triple bonds in pi-spacers and five reference dyes (TC, TC105, TPC1, D5, and TH208) without triple bonds were applied in dye-sensitized solar cells to study the influence of triple bonds as pi-spacer units on their photoelectrochemical properties and dye-sensitized solar cells (DSCs) performance. Results show that the introduction of triple bond could red-shift the dye's absorption spectrum due to the enhancement of the pi-spacer. However, the spectrum red-shift is much less than that of the introduction of double bond because of more electronegativity of triple bond. The incident photon-to-current conversion efficiency reveals that the electron transfer yield (Phi(nu)(ET)) of DSCs becomes larger with the introduction of triple bond. Electrochemical impedance spectroscopy analysis reveals that the introduction of triple bond almost does not change the electron lifetimes in TiO2 films but decreases the effective diffusion lengths.

  • 31. Teng, Chao
    et al.
    Yang, Xichuan
    Yuan, Chunze
    Li, Chaoyan
    Chen, Ruikui
    Tian, Haining
    Li, Shifeng
    Hagfeldt, Anders
    Sun, Licheng.
    Two Novel Carbazole Dyes for Dye-Sensitized Solar Cells with Open-Circuit Voltages up to 1 V Based on Br-/Br3- Electrolytes.2009In: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 11, no 23, p. 5542-5545Article in journal (Refereed)
    Abstract [en]

    Dye-sensitized solar cells (DSCs) based on two novel carbazole dyes and a Br-/Br3- redox mediator in dry CH3CN solns. as electrolytes yielded a Voc of 1.156 V and a η value of 3.68% and a Voc of 0.939 V and a η value of 5.22% under simulated AM 1.5, resp. The dyes have more pos. HOMO levels (1.59 and 1.38 V vs NHE) than the redox potential of Br-/Br3--based electrolytes, which have sufficient driving force to regenerate dyes. Under similar conditions with an I-/I3- instead of a Br-/Br3- redox mediator, DSCs sensitized by the dyes produced a Voc of 0.696 V and a η value of 2.36% and a Voc of 0.621 V and a η value of 4.10%, resp. [on SciFinder(R)]

  • 32.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Molecular Catalyst Immobilized Photocathodes for Water/Proton and Carbon Dioxide Reduction2015In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 8, no 22, p. 3746-3759Article, review/survey (Refereed)
    Abstract [en]

    As one of the components in a tandem photoelectrochemical cell for solar-fuel production, the photocathode carries out the reduction reaction to convert solar light and the corresponding substrate (e.g., proton and CO2) into target fuels. Immobilizing molecular catalysts onto the photocathode is a promising strategy to enhance the interfacial electron/hole-transfer process and to improve the stability of the catalysts. Furthermore, the molecular catalysts are beneficial in improving the selectivity of the reduction reaction, particularly for CO2 reduction. On the photocathode, the binding mode of the catalysts and the arrangement between the photosensitizer and the catalyst also play crucial roles in the performance and stability of the final device. How to firmly and effectively immobilize the catalyst on the photoelectrode is now becoming a scientific question. Recent publications on molecular catalyst immobilized photocathodes are therefore surveyed.

  • 33. Tian, Haining
    Solid-State Perovskite-Sensitized p-Type Mesoporous Nickel Oxide Solar Cells2014In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 7, no 8, p. 2150-2153Article in journal (Refereed)
  • 34.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Solid-state p-type dye-sensitized solar cells: progress, potential applications and challenges2019In: Sustainable Energy & Fuels, ISSN 2398-4902, Vol. 3, no 4, p. 888-898Article in journal (Refereed)
    Abstract [en]

    The fabrication of solid-state p-type dye-sensitized solar cells (p-ssDSCs) using electron transport materials instead of the conventional I-/I3- redox couple in liquid devices can completely eliminate the liquid phase and enhance the photovoltage. The performance of p-ssDSCs has been improved by optimizing the dyes and electron-transport materials. Moreover, p-ssDSCs provide a possibility to fabricate solid-state tandem dye-sensitized solar cells and show promising application in dye-sensitized solar fuel devices as well. Herein, the development of p-ssDSCs has been overviewed, their potential applications have been discussed, and the challenges remaining in p-ssDSCs have been highlighted.

  • 35. Tian, Haining
    et al.
    Bora, Ilkay
    Jiang, Xiao
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Gabrielsson, Erik
    Karlsson, Karl Martin
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Sun, Licheng
    Modifying organic phenoxazine dyes for efficient dye-sensitized solar cells2011In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 33, p. 12462-12472Article in journal (Refereed)
    Abstract [en]

    Four organic dyes bearing the phenoxazine chromophore have been synthesized and applied in dye-sensitized solar cells (DSCs). The effect of different dye structures on the performance of the DSCs was investigated systematically with photophysical, photovoltaic as well as photoelectrochemical methods. Due to the slow recombination process between injected electrons and electrolyte, the IB3 dye with two 2,4-dibutoxyphenyl units showed the best efficiency of 7.0% under 100 mW cm(-2) light illumination in the liquid state-DSCs. Moreover, the phenoxazine dyes-based solid state-DSCs were fabricated for the first time. With the IB4 dye, a higher efficiency of 3.2% has been achieved under the same light intensity.

  • 36. Tian, Haining
    et al.
    Gabrielsson, Erik
    Lohse, Peter William
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Vlachopoulos, Nikolaos
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Kloo, Lars
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Sun, Licheng
    Development of an organic redox couple and organic dyes for aqueous dye-sensitized solar cells2012In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 5, no 12, p. 9752-9755Article in journal (Refereed)
    Abstract [en]

    A water-soluble organic redox couple (TT-/DTT) and new organic dyes (D45 and D51) have been developed for aqueous dye-sensitized solar cells (DSCs). An optimal efficiency of 3.5% was obtained using the D51 dye and an optimized electrolyte composition. The highest IPCE value obtained was 68% at 460 nm.

  • 37. Tian, Haining
    et al.
    Gabrielsson, Erik
    Yu, Ze
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Kloo, Lars
    Sun, Licheng
    A thiolate/disulfide ionic liquid electrolyte for organic dye-sensitized solar cells based on Pt-free counter electrodes2011In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 47, no 36, p. 10124-10126Article in journal (Refereed)
    Abstract [en]

    The ionic liquid, 1-ethyl-3-methylimidazolium tetracyanoborate, was employed to prepare a thiolate/disulfide ionic liquid electrolyte with low viscosity for organic dye-sensitized solar cells (DSCs). CoS was introduced and showed better photovoltaic performance in DSCs than the ubiquitous platinized FTO CE.

  • 38. Tian, Haining
    et al.
    Jiang, Xiao
    Yu, Ze
    Kloo, Lars
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    Sun, Licheng
    Efficient Organic-Dye-Sensitized Solar Cells Based on an Iodine-Free Electrolyte2010In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 49, no 40, p. 7328-7331Article in journal (Refereed)
  • 39.
    Tian, Haining
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Nemeth, Brigitta
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Berggren, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Molecular Biomimetics.
    Tian, Lei
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hydrogen evolution by a photoelectrochemical cell based on a Cu2O-ZnO-[FeFe] hydrogenase electrode2018In: Journal of Photochemistry and Photobiology A: Chemistry, ISSN 1010-6030, E-ISSN 1873-2666, Vol. 366, p. 27-33Article in journal (Refereed)
    Abstract [en]

    A Cu2O-ZnO-hydrogenase photocathode possessed enzyme/semiconductor junction has been constructed by immobilizing a biological protein catalyst, hydrogenase-CrHydA1 enzyme on the ZnO protected Cu2O electrode. With light illumination, a photocurrent of 0.8 mA/cm2 at 0.15 V vs. RHE was obtained and hydrogen was successfully detected from the photocathode in photoelectrochemical measurements with Faradaic efficiency of ca. 1%. The construction as well as the stability of the system are also reported. The result shows that this biohybrid photocathode is capable of photocatalytic proton reduction under mild conditions.

  • 40.
    Tian, Haining
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Oscarsson, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Gabrielsson, Erik
    KTH, Stockholm.
    Eriksson, Susanna K.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Lindblad, Rebecka
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Xu, Bo
    Hao, Yan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Erik M. J.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Gardner, James M.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Rensmo, Håkan
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Molecular and condensed matter physics.
    Sun, Licheng
    KTH, Stockholm.
    Enhancement of p-Type Dye-Sensitized Solar Cell Performance by Supramolecular Assembly of Electron Donor and Acceptor2014In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 4, p. 4282-Article in journal (Refereed)
    Abstract [en]

    Supramolecular interactions based on porphyrin and fullerene derivatives were successfully adopted to improve the photovoltaic performance of p-type dye-sensitized solar cells (DSCs). Photoelectron spectroscopy (PES) measurements suggest a change in binding configuration of ZnTCPP after co-sensitization with C60PPy, which could be ascribed to supramolecular interaction between ZnTCPP and C60PPy. The performance of the ZnTCPP/C60PPy-based p-type DSC has been increased by a factor of 4 in comparison with the DSC with the ZnTCPP alone. At 560 nm, the IPCE value of DSCs based on ZnTCPP/C60PPy was a factor of 10 greater than that generated by ZnTCPP-based DSCs. The influence of different electrolytes on charge extraction and electron lifetime was investigated and showed that the enhanced V-oc from the Co2+/(3+)(dtbp)(3)-based device is due to the positive E-F shift of NiO.

  • 41.
    Tian, Haining
    et al.
    KTH, Royal Institue of Technology.
    Soto, Andrea
    Xu, Bo
    Sun, Licheng
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Fabregat-Santiago, Francisco
    Mora-Sero, Ivan
    Kang, Yong Soo
    Bisquert, Juan
    Barea, Eva M.
    Effect of the Chromophores Structures on the Performance of Solid-State Dye Sensitized Solar Cells2014In: Nano, ISSN 1793-2920, Vol. 9, no 5, p. 1440005-Article in journal (Refereed)
    Abstract [en]

    The er effect of metal-free chromophores on dye-sensitized solar cell performance is investigated. Solid state dye-sensitized solar cells (ssDSCs) using dirfferent molecular sensitizers based on tri-phenylamine (TPA) with thiophene linkers and different alkyl chain in the donor unit have been characterized using impedance spectroscopy (IS). We show that different molecular structures play a fundamental role on solar cell performance, by the effect produced on TiO2 conduction band position and in the recombination rate. Dye structure and its electronic properties are the main factors that control the recombination, the capacitance and the efficiency of the cells. A clear trend between the performance of the cell and the optimization level of the blocking effect of the dye structure has been identified in the solid state solar cells with Spiro-OMeTAD hole conductor.

  • 42.
    Tian, Haining
    et al.
    Department of Chemistry, Center of Molecular Devices, School of Chemical Science and Engineering, Royal Institute of Technology (KTH), Stockholm, Sweden .
    Sun, Licheng
    Iodine-free redox couples for dye-sensitized solar cells2011In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 21, no 29, p. 10592-10601Article in journal (Refereed)
    Abstract [en]

    Redox couples, as one of the crucial components of dye-sensitized solar cells, were studied for many years. Due to the many drawbacks of I-/I3- electrolyte, scientists have paid more attention to seeking other alternative electrolyte systems. The best efficiency of iodine-free redox couple-based DSCs, 7.5%, was achieved by ferrocene/ferrocenium redox couple under AM 1.5 G, 100 mW cm-2 light illumination and other redox couples also show the promising future in DSCs. In this feature article, the authors systematically present three series of iodine-free redox couples including metal-complexes, inorg. and pure org. redox couples, and further compare the different photovoltaic and photophys. properties of these redox couples. As a consequence, the goals of this article are to show the important progress achieved in the redox couples research area of DSCs and analyze the advantages as well as the disadvantages of these redox couples to speed up the further development of iodine-free redox couples in the future.

  • 43. Tian, Haining
    et al.
    Yang, Xichuan
    Chen, Ruikui
    Hagfeldt, Anders
    Sun, Licheng.
    A metal-free "black dye" for panchromatic dye-sensitized solar cells.2009In: Energy Environ. Sci., ISSN 1754-5706, Vol. 2, no 6, p. 674-677Article in journal (Refereed)
    Abstract [en]

    A novel metal-free "black dye" was designed and synthesized for panchromatic dye-sensitized solar cells. Based on this dye, the broader incident photon-to-current conversion efficiency spectrum was obtained over the whole visible range extending into the near-IR region up to 920 nm. [on SciFinder(R)]

  • 44. Tian, Haining
    et al.
    Yang, Xichuan
    Chen, Ruikui
    Pan, Yuzhen
    Li, Lin
    Hagfeldt, Anders
    Sun, Licheng.
    Phenothiazine derivatives for efficient organic dye-sensitized solar cells.2007In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 36, p. 3741-3743Article in journal (Refereed)
    Abstract [en]

    Novel org. dyes based on the phenothiazine (PTZ) chromophore were designed and synthesized for dye-sensitized solar cells, which give solar energy-to-electricity conversion efficiency (η)of up to 5.5% in comparison with the ref. Ru-complex (N3 dye) with an η value of 6.2% under similar exptl. conditions. [on SciFinder(R)]

  • 45. Tian, Haining
    et al.
    Yang, Xichuan
    Chen, Ruikui
    Zhang, Rong
    Hagfeldt, Anders
    Sun, Licheng.
    Effect of Different Dye Baths and Dye-Structures on the Performance of Dye-Sensitized Solar Cells Based on Triphenylamine Dyes.2008In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 112, no 29, p. 11023-11033Article in journal (Refereed)
    Abstract [en]

    Triphenylamine dyes were designed and synthesized as photosensitizers for dye-sensitized solar cells (DSSCs). Different substituted phenylene units, 2,2';5',2''-ter-thiophene (TT) and dithieno[3,2-b;2',3'-d]thiophene (DTT) serve as the π-spacers - the electron acceptors use cyanoacrylic acid or rhodanine-3-acetic acid units. A detailed study on the relation between the dye structure, and photophys., photoelectrochem. properties and performance of DSSCs is described here. By substituting the phenylene group with electron-withdrawing units as π-spacers or replacing the cyanoacrylic acid with rhodanine-3-acetic acid units as electron acceptors, bathochromic shift of absorption spectra is achieved. Significant differences in the redox potential of these dyes are due to small structure changes. The different dye baths for semiconductor sensitization have a crucial effect on the performance of the DSSCs due to the different absorbed amt., absorption spectra and binding modes of anchored dyes on the TiO2 surface in various solvents. From optimized dye bath and mol. structure, TPC1 shows a prominent solar-to-electricity conversion efficiency (η), 5.33% (JSC = 9.7 mA/cm2, VOC = 760 mV, ff = 0.72), under simulated AM 1.5 G irradn. (100 mW/cm2). DFT showed the electron distribution and the intramol. charge transfer (HOMO→LUMO) of the dyes. From the calcn. results of the selected dyes, the authors can also find the cyanoacrylic acid unit better than the rhodanine-3-acetic acid unit as electron acceptor. Also, the electron-withdrawing groups on phenylene units as π-spacers show the neg. effect on the performance of the org. DSSCs. [on SciFinder(R)]

  • 46. Tian, Haining
    et al.
    Yang, Xichuan
    Cong, Jiayan
    Chen, Ruikui
    Liu, Jing
    Hao, Yan
    Hagfeldt, Anders
    Sun, Licheng.
    Tuning of phenoxazine chromophores for efficient organic dye-sensitized solar cells.2009In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 41, p. 6288-6290Article in journal (Refereed)
    Abstract [en]

    Through introducing an energy antenna system into a simple phenoxazine dye (TH301), a novel and efficient dye TH305 was designed and synthesized for application in a dye sensitized solar cell with prominent overall conversion efficiency of 7.7%. [on SciFinder(R)]

  • 47. Tian, Haining
    et al.
    Yang, Xichuan
    Cong, Jiayan
    Chen, Ruikui
    Teng, Chao
    Liu, Jing
    Hao, Yan
    Wang, Lei
    Sun, Licheng.
    Effect of different electron donating groups on the performance of dye-sensitized solar cells.2010In: Dyes and pigments, ISSN 0143-7208, E-ISSN 1873-3743, Vol. 84, no 1, p. 62-68Article in journal (Refereed)
    Abstract [en]

    A series of org. sensitizers contg. identical π-spacers and electron acceptors but different, arom. amine electron-donating groups, were used in dye-sensitized solar cells to study the effect of the electron donating groups on device performance. The derived photophys. and photovoltaic properties, as well as d. functional theory calcns., revealed that the tetrahydroquinoline dye was prone to aggregate upon the surface of titanium dioxide owing to the dye's planar structure. A 45% improvement in efficiency of a tetrahydroquinoline dye based cell was achieved when chenodeoxycholic acid was employed as co-adsorbent. However, the airscrew type of triphenylamine unit and Y type structure of the substituted phenothiazine framework suppressed dye aggregation on titanium dioxide. The efficiency of a phenothiazine dye-based cell fabricated using satd. co-adsorbent in dichloromethane was only 15% greater than that achieved in the absence of co-adsorbent. Electrochem. Impedance Spectroscopy was used to det. the interfacial charge transfer process occurring in solar cells that employed different dyes in both the absence and presence of chenodeoxycholic acid as co-adsorbent. [on SciFinder(R)]

  • 48. Tian, Haining
    et al.
    Yang, Xichuan
    Pan, Jingxi
    Chen, Ruikui
    Liu, Ming
    Zhang, Qingyu
    Hagfeldt, Anders
    Sun, Licheng.
    A triphenylamine dye model for the study of intramolecular energy transfer and charge transfer in dye-sensitized solar cells.2008In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 18, no 21, p. 3461-3468Article in journal (Refereed)
    Abstract [en]

    A novel dye (2TPA-R), contg. two triphenylamine (TPA) units connected by a vinyl group and rhodanine-3-acetic acid as the electron acceptor, is designed and synthesized successfully to reveal the working principles of org. dye in dye-sensitized solar cells (DSSCs). 2TPA and TPA-R, which consist of two TPA units connected by vinyl and a TPA unit linked with rhodanine-3-acetic acid, resp., are also synthesized as refs. to study the intramol. energy transfer (EnT) and charge transfer (ICT) processes of 2TPA-R in CH2Cl2 soln. and on a TiO2 surface. The results suggest that the intramol. EnT and ICT processes show a pos. effect on the performance of DSSCs. However, the flexible structure and less-adsorbed amt. of dye on TiO2 may make it difficult to improve the efficiency of DSSCs. This study on intramol. EnT and ICT processes acts as a guide for the design and synthesis of efficient org. dyes in the future. [on SciFinder(R)]

  • 49. Tian, Haining
    et al.
    Yu, Ze
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry.
    Kloo, Lars
    Sun, Licheng
    Organic Redox Couples and Organic Counter Electrode for Efficient Organic Dye-Sensitized Solar Cells2011In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 133, no 24, p. 9413-9422Article in journal (Refereed)
    Abstract [en]

    A series of organic thiolate/disulfide redox couples have been synthesized and have been studied systematically in dye-sensitized solar cells (DSCs) on the basis of an organic dye (TH305). Photophysical, photoelectrochemical, and photovoltaic measurements were performed in order to get insights into the effects of different redox couples on the performance of DSCs. The polymeric, organic poly(3,4-ethylenedioxythiophene) (PEDOT) material has also been introduced as counter electrode in this kind of noniodine-containing DSCs showing a promising conversion efficiency of 6.0% under AM 1.5G, 100 mW.cm(-2) light illumination. Detailed studies using electrochemical impedance spectroscopy and linear-sweep voltammetry reveal that the reduction of disulfide species is more efficient on the PEDOT counter electrode surface than on the commonly used platinized conducting glass electrode. Both pure and solvated ionic-liquid electrolytes based on a thiolate anion have been studied in the DSCs. The pure and solvated ionic-liquid-based electrolytes containing an organic redox couple render efficiencies of 3.4% and 1.2% under 10 mW.cm(-2) light illumination, respectively.

  • 50.
    Tian, Lei
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Föhlinger, Jens
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Pati, Palas Baran
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Zhang, Zhi-Bin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Lin, Junzhong
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    Yang, Wenxing
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Johansson, Malin B
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Kubart, Tomas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Sun, Junliang
    Stockholm Univ, Dept Mat & Environm Chem, S-10691 Stockholm, Sweden.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Hammarström, Leif
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Tian, Haining
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - Ångström, Physical Chemistry.
    Ultrafast dye regeneration in a core-shell NiO-dye-TiO2 mesoporous film2018In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 20, no 1, p. 36-40Article in journal (Refereed)
    Abstract [en]

    In this study, a core-shell NiO-dye-TiO2 mesoporous film was fabricated for the first time, utilizing atomic layer deposition technique and a newly designed triphenylamine dye. The structure of the film was confirmed by SEM, TEM, and EDX. Excitation of the dye led to efficient and fast charge separation, by hole injection into NiO, followed by an unprecedentedly fast dye regeneration (t1/2 [less-than-or-equal] 500 fs) by electron transfer to TiO2. The resulting charge separated state showed a pronounced transient absorption spectrum caused by the Stark effect, and no significant decay was found within 1.9 ns. This indicates that charge recombination between NiO and TiO2 is much slower than that between the NiO and the reduced dye in the absence of the TiO2 layer (t1/2 [approximate] 100 ps).

12 1 - 50 of 65
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