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Publications (10 of 69) Show all publications
Materna, K. L., Lalaoui, N., Laureanti, J. A., Walsh, A. P., Pettersson-Rimgard, B., Lomoth, R., . . . Hammarström, L. (2020). Using Surface Amide Couplings to Assemble Photocathodes for Solar Fuel Production Applications. ACS Applied Materials and Interfaces, 12(4), 4501-4509
Open this publication in new window or tab >>Using Surface Amide Couplings to Assemble Photocathodes for Solar Fuel Production Applications
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2020 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 4, p. 4501-4509Article in journal (Refereed) Published
Abstract [en]

A facile surface amide-coupling method was examined to attach dye and catalyst molecules to silatrane-decorated NiO electrodes. Using this method, electrodes with a push-pull dye were assembled and characterized by photoelectrochemistry and transient absorption spectroscopy. The dye-sensitized electrodes exhibited hole injection into NiO and good photoelectrochemical stability in water, highlighting the stability of the silatrane anchoring group and the amide linkage. The amide-coupling protocol was further applied to electrodes that contain a molecular proton reduction catalyst for use in photocathode architectures. Evidence for catalyst reduction was observed during photoelectrochemical measurements and via photocathodes.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2020
Keywords
solar fuels, photocathode, nickel oxide, silatrane, amide coupling
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-406495 (URN)10.1021/acsami.9b19003 (DOI)000510532000032 ()31872996 (PubMedID)
Funder
Swedish Energy Agency, 11674-8
Available from: 2020-03-11 Created: 2020-03-11 Last updated: 2020-03-11Bibliographically approved
Huang, J., Xu, B., Tian, L., Pati, P. B., Etman, A. S., Sun, J., . . . Tian, H. (2019). A heavy metal-free CuInS2 quantum dot sensitized NiO photocathode with a Re molecular catalyst for photoelectrochemical CO2 reduction. Chemical Communications, 55(55), 7918-7921
Open this publication in new window or tab >>A heavy metal-free CuInS2 quantum dot sensitized NiO photocathode with a Re molecular catalyst for photoelectrochemical CO2 reduction
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2019 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 55, no 55, p. 7918-7921Article in journal (Refereed) Published
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.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2019
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-390783 (URN)10.1039/c9cc04222a (DOI)000474306200003 ()31215919 (PubMedID)
Funder
Swedish Energy Agency, 11674-8Göran Gustafsson Foundation for Research in Natural Sciences and MedicineStiftelsen Olle Engkvist Byggmästare
Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2019-08-16Bibliographically approved
Xu, B., Wrede, S., Curtze, A., Tian, L., Pati, P. B., Kloo, L., . . . Tian, H. (2019). An Indacenodithieno[3,2-b]thiophene-Based Organic Dye for Solid-State p-Type Dye-Sensitized Solar Cells. ChemSusChem, 12(14), 3243-3248
Open this publication in new window or tab >>An Indacenodithieno[3,2-b]thiophene-Based Organic Dye for Solid-State p-Type Dye-Sensitized Solar Cells
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2019 (English)In: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 12, no 14, p. 3243-3248Article in journal (Refereed) Published
Abstract [en]

An indacenodithieno[3,2-b]thiophene (IDTT) unit is used as a linker moiety to design a new p-type dye-TIP-for solid-state p-type dye-sensitized solar cells. Solar cells based on the TIP dye offered an efficiency of 0.18 % with an open-circuit photovoltage of 550 mV and a short-circuit photocurrent density of 0.86 mA cm(-2), which is better than those of two reference dyes, PB6 and BH4. Charge lifetime experiments reveal that the IDTT linker-based TIP dye significantly suppresses charge recombination losses in the devices.

Keywords
dye-sensitized solar cells, energy materials, p-type dye, S heterocycles, solid state
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-393128 (URN)10.1002/cssc.201901102 (DOI)000478633900003 ()31144448 (PubMedID)
Funder
Swedish Energy Agency, 43599-1Stiftelsen Olle Engkvist Byggmästare
Available from: 2019-09-24 Created: 2019-09-24 Last updated: 2019-09-24Bibliographically approved
Liu, A., Tai, C.-W., Hola, K. & Tian, H. (2019). Hollow polymer dots: nature-mimicking architecture for efficient photocatalytic hydrogen evolution reaction. Journal of Materials Chemistry A, 7(9), 4797-4803
Open this publication in new window or tab >>Hollow polymer dots: nature-mimicking architecture for efficient photocatalytic hydrogen evolution reaction
2019 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 9, p. 4797-4803Article in journal (Refereed) Published
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.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-380464 (URN)10.1039/c8ta12146j (DOI)000460687400052 ()
Funder
Swedish Energy Agency, 44641-1
Available from: 2019-03-28 Created: 2019-03-28 Last updated: 2019-03-28Bibliographically approved
Tian, L., Törndahl, T., Ling, J., Pati, P. B., Zhang, Z.-B., Kubart, T., . . . Tian, H. (2019). Mechanistic Insights into Solid-State p-Type Dye-Sensitized Solar Cells. The Journal of Physical Chemistry C, 123(43), 26151-26160
Open this publication in new window or tab >>Mechanistic Insights into Solid-State p-Type Dye-Sensitized Solar Cells
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2019 (English)In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 123, no 43, p. 26151-26160Article in journal (Refereed) Published
Abstract [en]

The study of p-type dye sensitized solar cells (p-DSCs) is appealing but challenging. Although the devices have been studied for 20 years, the light conversion efficiency lags far behind those of n-DSCs. Very recently, on the basis of a core-shell structure, a novel solid-state p-DSC (p-ssDSCs) has been fabricated, which showed great enhancement in open-circuit voltage and dye regeneration rate. To further improve the performance of such devices, charge diffusion, recombination process, and the main limiting factors have to be understood. In the present paper, core-shell p-ssDSCs with ZnO as an electron conductor were fabricated by atomic layer deposition. The charge transport time was determined to be ca. 0.1 ms, which is about 2 orders of magnitude faster than those of typical liquid devices with I-/I-3(-) as a redox mediator. As a consequence, the devices exhibit the highest reported charge diffusion coefficient (D-d)' among p-DSCs. It is ascribed to an electron-limiting diffusion process by the ambipolar diffusion model, suggesting a different charge-transport-determining mechanism in contrast to liquid p-DSCs. The charge recombination rate is 1-2 orders of magnitude slower than its charge transport time, mandating that the estimated charge collection efficiency is near unity. Detailed analysis of the incident photon-to-electron conversion efficiency suggests that the energy conversion efficiency in these p-ssDSCs is currently limited by a large fraction of dyes that is not fully electrically connected in the device.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Physical Chemistry Engineering and Technology
Identifiers
urn:nbn:se:uu:diva-397591 (URN)10.1021/acs.jpcc.9b08251 (DOI)000493865700013 ()
Available from: 2019-11-25 Created: 2019-11-25 Last updated: 2020-01-15Bibliographically approved
Tian, H. (2019). Solid-state p-type dye-sensitized solar cells: progress, potential applications and challenges. Sustainable Energy & Fuels, 3(4), 888-898
Open this publication in new window or tab >>Solid-state p-type dye-sensitized solar cells: progress, potential applications and challenges
2019 (English)In: Sustainable Energy & Fuels, ISSN 2398-4902, Vol. 3, no 4, p. 888-898Article in journal (Refereed) Published
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.

National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-383872 (URN)10.1039/c8se00581h (DOI)000467219500001 ()
Funder
Swedish Energy Agency, 43237-1
Available from: 2019-06-14 Created: 2019-06-14 Last updated: 2019-06-14Bibliographically approved
Xu, B., Tian, L., Etman, A. S., Sun, J. & Tian, H. (2019). Solution-processed nanoporous NiO-dye-ZnO photocathodes: Toward efficient and stable solid-state p-type dye-sensitized solar cells and dye-sensitized photoelectrosynthesis cells. Nano Energy, 55, 59-64
Open this publication in new window or tab >>Solution-processed nanoporous NiO-dye-ZnO photocathodes: Toward efficient and stable solid-state p-type dye-sensitized solar cells and dye-sensitized photoelectrosynthesis cells
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2019 (English)In: Nano Energy, ISSN 2211-2855, E-ISSN 2211-3282, Vol. 55, p. 59-64Article in journal (Refereed) Published
Abstract [en]

A solution-processed NiO-dye-ZnO photocathode was developed for applications in both solid-state p-type dye-sensitized solar cells (p-ssDSCs) and p-type dye-sensitized photoelectrosynthesis cells (p-DSPECs). In p-ssDSCs, the solar cell using ZnO as electron transport material showed a short circuit current, up to 680 mu A cm(-2), which is 60-fold larger than that previously reported device using TiO2 as electron transport material with similar architecture. In the p-DSPECs, a remarkable photocurrent of 100 mu A cm(-2) was achieved in a pH = 5.0 acetate buffer solution under a bias potential at 0.05 V vs RHE with platinum as the proton reduction catalyst. A Faradaic efficiency approaching 100% for the H-2 evolution reaction was obtained after photoelectrolysis for 9 h. Importantly, the solution-processed NiO-dye-ZnO photocathode exhibited excellent long-term stability in both p-ssDSCs and p-DSPECs. To the best of our knowledge, this is the first study where a solution-processable, nanoporous NiO-dye-ZnO photocathode is used for both p-ssDSCs and p-DSPECs having both excellent device performance and stability.

Keywords
Dye-sensitized photocathode, P-type, Solution-processed, Solid-state, Solar cell, Solar fuel
National Category
Materials Chemistry Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-374114 (URN)10.1016/j.nanoen.2018.10.054 (DOI)000454636200007 ()
Funder
Swedish Energy Agency, 43599-1Swedish Energy Agency, 11674-8
Note

Bo Xu and Lei Tian contributed equally to this work.

Available from: 2019-01-23 Created: 2019-01-23 Last updated: 2020-01-15Bibliographically approved
Huang, J., Gilbert Gatty, M., Xu, B., Pati, P. B., Etman, A. S., Tian, L., . . . Tian, H. (2018). Covalently linking CuInS2 quantum dots with a Re catalyst by click reaction for photocatalytic CO2 reduction. Dalton Transactions, 47(31), 10775-10783
Open this publication in new window or tab >>Covalently linking CuInS2 quantum dots with a Re catalyst by click reaction for photocatalytic CO2 reduction
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2018 (English)In: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 47, no 31, p. 10775-10783Article in journal (Refereed) Published
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.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-363108 (URN)10.1039/c8dt01631c (DOI)000441151700051 ()30019727 (PubMedID)
Funder
Swedish Research CouncilSwedish Energy AgencyGöran Gustafsson Foundation for promotion of scientific research at Uppala University and Royal Institute of TechnologyStiftelsen Olle Engkvist Byggmästare
Available from: 2018-10-15 Created: 2018-10-15 Last updated: 2018-10-15Bibliographically approved
Gilbert Gatty, M., Pullen, S., Sheibani, E., Tian, H., Ott, S. & Hammarström, L. (2018). Direct evidence of catalyst reduction on dye and catalyst co-sensitized NiO photocathodes by mid-infrared transient absorption spectroscopy. Chemical Science, 9(22), 4983-4991
Open this publication in new window or tab >>Direct evidence of catalyst reduction on dye and catalyst co-sensitized NiO photocathodes by mid-infrared transient absorption spectroscopy
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2018 (English)In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 9, no 22, p. 4983-4991Article in journal (Refereed) Published
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.

National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-358380 (URN)10.1039/c8sc00990b (DOI)000434693300008 ()
Funder
Swedish Energy Agency, 11645-5
Available from: 2018-08-29 Created: 2018-08-29 Last updated: 2018-08-29Bibliographically approved
Tian, H., Nemeth, B., Berggren, G. & Tian, L. (2018). Hydrogen evolution by a photoelectrochemical cell based on a Cu2O-ZnO-[FeFe] hydrogenase electrode. Journal of Photochemistry and Photobiology A: Chemistry, 366, 27-33
Open this publication in new window or tab >>Hydrogen evolution by a photoelectrochemical cell based on a Cu2O-ZnO-[FeFe] hydrogenase electrode
2018 (English)In: Journal of Photochemistry and Photobiology A: Chemistry, ISSN 1010-6030, E-ISSN 1873-2666, Vol. 366, p. 27-33Article in journal (Refereed) Published
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.

National Category
Chemical Sciences
Identifiers
urn:nbn:se:uu:diva-371529 (URN)10.1016/j.jphotochem.2018.01.035 (DOI)000452577600005 ()
Funder
Stiftelsen Olle Engkvist Byggmästare, 2015/456J. Gust. Richert stiftelse, 2016-00231Swedish Energy Agency, 111674-8Swedish Research Council, 621-2014-5670Swedish Research Council Formas, 213-2014-880Wenner-Gren Foundations
Available from: 2018-12-21 Created: 2018-12-21 Last updated: 2019-01-16Bibliographically approved
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