uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 112) Show all publications
Svanström, S., Jacobsson, J., Boschloo, G., Johansson, E., Rensmo, H. & Cappel, U. B. (2020). Degradation Mechanism of Silver Metal Deposited on Lead Halide Perovskites. ACS Applied Materials and Interfaces, 12(6), 7212-7221
Open this publication in new window or tab >>Degradation Mechanism of Silver Metal Deposited on Lead Halide Perovskites
Show others...
2020 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 6, p. 7212-7221Article in journal (Refereed) Published
Abstract [en]

Lead halide perovskite solar cells have significantly increased in both efficiency and stability over the last decade. An important aspect of their longterm stability is the reaction between the perovskite and other materials in the solar cell. This includes the contact materials and their degradation if they can potentially come into contact through, e.g., pinholes or material diffusion and migration. Here, we explore the interactions of silver contacts with lead halide perovskites of different compositions by using a model system where thermally evaporated silver was deposited directly on the surface of the perovskites. Using X-ray photoelectron spectroscopy with support from scanning electron microscopy, X-ray diffraction, and UV-visible absorption spectroscopy, we studied the film formation and degradation of silver on perovskites with different compositions. The deposited silver does not form a continuous silver film but instead tends to form particles on a bare perovskite surface. These particles are initially metallic in character but degrade into AgI and AgBr over time. The degradation and migration appear unaffected by the replacement of methylammonium with cesium but are significantly slowed down by the complete replacement of iodide with bromide. The direct contact between silver and the perovskite also significantly accelerates the degradation of the perovskite, with a significant loss of organic cations and the possible formation of PbO, and, at the same time, changed the surface morphology of the iodide-rich perovskite interface. Our results further indicate that an important degradation pathway occurred through gas-phase perovskite degradation products. This highlights the importance of control over the interface materials and the use of completely hermetical barrier layers for the long-term stability and therefore the commercial viability of silver electrodes.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2020
Keywords
perovskite solar cells, electrode stability, X-ray photoelectron spectroscopy, interface chemistry, noble metal electrodes
National Category
Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-407282 (URN)10.1021/acsami.9b20315 (DOI)000514256400040 ()31958007 (PubMedID)
Funder
Swedish Research Council, VR 2018-04125Swedish Research Council, 2018-06465Swedish Research Council, 2018-04330Swedish Foundation for Strategic Research , RMA15-0130Swedish Energy Agency, P43549-1StandUpÅForsk (Ångpanneföreningen's Foundation for Research and Development)Göran Gustafsson Foundation for Research in Natural Sciences and Medicine
Available from: 2020-03-23 Created: 2020-03-23 Last updated: 2020-03-23Bibliographically approved
Johansson, E. (2020). The Photon Battery  - a new concept for low cost, large scale or high energy density electricity storage.
Open this publication in new window or tab >>The Photon Battery  - a new concept for low cost, large scale or high energy density electricity storage
2020 (English)Report (Other academic)
Abstract [en]

In this report a photon battery is presented as a new type of electrical energy storage. The battery charging is based on conversion of electricity into photons and these photons are absorbed by an energy storage material, which is therefore heated to high temperatures. To extract electricity when needed, photons emitted from the hot energy storage material can be converted back to electricity by photovoltaics. The basic principles of the energy cycle are presented and the efficiency of the photon battery is discussed. The maximum energy density for different types of materials are estimated and examples of application of photon batteries for low cost and large scale electricity storage is suggested, and higher energy density applications are also discussed.

Publisher
p. 7
Keywords
Energy, Storage, Photovoltaic, Battery
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-403141 (URN)
Available from: 2020-01-24 Created: 2020-01-24 Last updated: 2020-01-24Bibliographically approved
Wu, H., Zhu, H., Erbing, A., Johansson, M. B., Mukherjee, S., Man, G., . . . Johansson, E. (2019). Bandgap Tuning of Silver Bismuth Iodide via Controllable Bromide Substitution for Improved Photovoltaic Performance. ACS APPLIED ENERGY MATERIALS, 2(8), 5356-5362
Open this publication in new window or tab >>Bandgap Tuning of Silver Bismuth Iodide via Controllable Bromide Substitution for Improved Photovoltaic Performance
Show others...
2019 (English)In: ACS APPLIED ENERGY MATERIALS, ISSN 2574-0962, Vol. 2, no 8, p. 5356-5362Article in journal (Refereed) Published
Abstract [en]

In this work, silver-bismuth-halide thin films, exhibiting low toxicity and good stability, were explored systemically by gradually substituting iodide, I, with bromide, Br, in the AgBi2I7 system. It was found that the optical bandgap can be tuned by varying the I/Br ratio. Moreover, the film quality was improved when introducing a small amount of Br. The solar cell was demonstrated to be more stable at ambient conditions and most efficient when incorporating 10% Br, as a result of decreased recombination originating from the increased grain size. Thus, replacing a small amount of I with Br was beneficial for photovoltaic performance.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2019
Keywords
lead-free solar cells, power conversion efficiency, bandgap, silver bismuth iodide, mixed-halide composition, grain size, density functional theory
National Category
Physical Chemistry Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-391056 (URN)10.1021/acsaem.9b00914 (DOI)000483434700003 ()
Funder
Swedish Research CouncilSwedish Energy AgencyCarl Tryggers foundation
Available from: 2019-08-18 Created: 2019-08-18 Last updated: 2019-12-18Bibliographically approved
Johansson, M. B., Philippe, B., Banerjee, A., Phuyal, D., Mukherjee, S., Chakraborty, S., . . . Johansson, E. (2019). Cesium Bismuth Iodide Solar Cells from Systematic Molar Ratio Variation of CsI and BiI3. Inorganic Chemistry, 58(18), 12040-12052
Open this publication in new window or tab >>Cesium Bismuth Iodide Solar Cells from Systematic Molar Ratio Variation of CsI and BiI3
Show others...
2019 (English)In: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 58, no 18, p. 12040-12052Article in journal (Refereed) Published
Abstract [en]

Metal halide compounds with photovoltaic properties prepared from solution have received increased attention for utilization in solar cells. In this work, low-toxicity cesium bismuth iodides are synthesized from solution, and their photovoltaic and, optical properties as well as electronic and crystal structures are investigated. The X-ray diffraction patterns reveal that a CsI/BiI3 precursor ratio of 1.5:1 can convert pure rhombohedral BiI3 to pure hexagonal Cs3Bi2I9, but any ratio intermediate of this stoichiometry and pure BiI3 yields a mixture containing the two crystalline phases Cs3Bi2I9 and BiI3, with their relative fraction depending on the CsI/BiI3 ratio. Solar cells from the series of compounds are characterized, showing the highest efficiency for the compounds with a mixture of the two structures. The energies of the valence band edge were estimated using hard and soft X-ray photoelectron spectroscopy for more bulk and surface electronic properties, respectively. On the basis of these measurements, together with UV-vis-near-IR spectrophotometry, measuring the band gap, and Kelvin probe measurements for estimating the work function, an approximate energy diagram has been compiled clarifying the relationship between the positions of the valence and conduction band edges and the Fermi level.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Inorganic Chemistry
Identifiers
urn:nbn:se:uu:diva-395308 (URN)10.1021/acs.inorgchem.9b01233 (DOI)000486565600024 ()31483638 (PubMedID)
Funder
Swedish Energy AgencySwedish Research CouncilSwedish Research Council FormasSwedish Foundation for Strategic Research
Available from: 2019-10-18 Created: 2019-10-18 Last updated: 2019-10-18Bibliographically approved
Bai, X., Yang, L., Hagfeldt, A., Johansson, E. & Jin, P. (2019). D35-TiO2 nano-crystalline film as a high performance visible-light photocatalyst towards the degradation of bis-phenol A. Chemical Engineering Journal, 355, 999-1010
Open this publication in new window or tab >>D35-TiO2 nano-crystalline film as a high performance visible-light photocatalyst towards the degradation of bis-phenol A
Show others...
2019 (English)In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 355, p. 999-1010Article in journal (Refereed) Published
Abstract [en]

Dye-sensitized photocatalytic suspension system for wastewater treatment is still limited in practice due to particle aggregation, fast charge carrier recombination, poor stability and recycling issue. In this study, we combine TiO2 nano-crystalline film with D35 organic dye to fabricate a new visible-light photocatalyst D35-TiO2, which exhibits excellent visible light absorption. Its transient photocurrent is almost 10 times higher than pure TiO2 under visible light illumination (lambda > 420 nm). Besides the well characterizations of the D35-TiO2 film, e.g., SEM, EDS, TEM, XRD, UV-Vis DRS, XPS, PL and I-T, degradation of bis-phenol A (BPA) is performed as the model reaction to test its photocatalytic activity. Meanwhile, we employ external bias in the reaction system to further enhance the photogenerated charge carrier separation, and improve the photocatalytic efficiency. Under the better experimental conditions of initial BPA concentration (5 mg/L), initial pH (pH 7), external bias (0.25 V) and sensitizer concentration (0.1 mM), BPA is almost completely degraded in 300 min, and the four intermediates are gradually mineralized. The ecotoxicity of BPA also decreases significantly after the photo-degradation. During the reaction, center dot O-2(-) plays a dominant role, meanwhile center dot OH and h(D35)(+) also contribute to the BPA degradation. After five cycles, the D35-TiO2 film still maintain the normal photocatalytic activity. Due to the high stability and recyclability, the D35-TiO2 nano-crystalline film provides a sustainable way for degrading micropollutants in wastewater.

Place, publisher, year, edition, pages
ELSEVIER SCIENCE SA, 2019
Keywords
Dye-sensitization, TiO2, Visible light, Nano-crystalline film
National Category
Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-363194 (URN)10.1016/j.cej.2018.08.061 (DOI)000445416900094 ()
Available from: 2018-10-18 Created: 2018-10-18 Last updated: 2018-10-18Bibliographically approved
Liu, J., Zhou, Q., Kyi Thein, N., Tian, L., Jia, D., Johansson, E. M. J. & Zhang, X. (2019). In situ growth of perovskite stacking layers for high-efficiency carbon-based hole conductor free perovskite solar cells. Journal of Materials Chemistry A, 7(22), 13777-13786
Open this publication in new window or tab >>In situ growth of perovskite stacking layers for high-efficiency carbon-based hole conductor free perovskite solar cells
Show others...
2019 (English)In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 7, no 22, p. 13777-13786Article in journal (Refereed) Published
Abstract [en]

The interfacial properties between a perovskite layer and carbon electrode are critical for the photovoltaic performance of carbon electrode-based perovskite solar cells (PSCs). Herein, a methylammonium lead mixed halide (MAPbIxBr3−x) perovskite layer is in situ grown on the top of a methylammonium lead iodide (MAPbI3) perovskite layer forming a MAPbI3/MAPbIxBr3−x perovskite stacking structure (PSS) to improve the interfacial properties at the perovskite/carbon electrode interface. The charge carrier dynamics in both the perovskite and the PSC device induced by the MAPbIxBr3−x perovskite stacking layer are studied using extensive characterization. The charge interfacial recombination at the perovskite/carbon electrode interface is significantly diminished using the PSS within the PSC, resulting in largely improved charge extraction and therefore high photovoltaic performance. The PSS-based PSC shows a power conversion efficiency of up to 16.2% (increased by 43% compared with that of a conventional MAPbI3-based PSC), which is among the highest efficiencies of carbon electrode-based hole conductor free PSCs. Meanwhile, the PSS-based PSC also exhibits good stability under both continuous illumination and storage under dark conditions. This work may provide a new avenue to fine tune the interfacial properties of carbon electrode-based PSCs for further improving their photovoltaic performance.

National Category
Materials Chemistry Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-388769 (URN)10.1039/c9ta02772f (DOI)000470928800035 ()
Funder
Swedish Energy AgencySwedish Research Council FormasSwedish Research CouncilGöran Gustafsson Foundation for promotion of scientific research at Uppala University and Royal Institute of Technology
Available from: 2019-07-05 Created: 2019-07-05 Last updated: 2019-07-05Bibliographically approved
Liu, J., Jia, D., Gardner, J. M., Johansson, E. & Zhang, X. (2019). Metal nanowire networks: Recent advances and challenges for new generation photovoltaics. MATERIALS TODAY ENERGY, 13, 152-185
Open this publication in new window or tab >>Metal nanowire networks: Recent advances and challenges for new generation photovoltaics
Show others...
2019 (English)In: MATERIALS TODAY ENERGY, ISSN 2468-6069, Vol. 13, p. 152-185Article, review/survey (Refereed) Published
Abstract [en]

Transparent conducting electrodes which allow photons passing through and simultaneously transfers the charge carriers are critical for the construction of high-performance photovoltaic cells. Electrodes based on metal oxides, such as indium-doped tin oxide (ITO) or fluorine-doped tin oxide (FTO), may have limited application in new generation flexible solar cells, which employ solution-processed roll-to-roll or ink-printing techniques toward large-area-fabrication approach, due to their brittleness and poor mechanical properties. Metal nanowire network (MNWN) emerges as a highly potential alternative candidate instead of ITO or FTO due to the high transparency, low sheet resistance, low cost, solution processable and compatibility with a flexible substrate for high throughput production. This feature article systematically summarizes the recent advances of the MNWNs, including new concepts and emerging strategies for the synthesis of metal nanowires (MNWs), various approaches for the preparation of MNWNs and comprehensively discusses the novel MNWN electrodes prepared on different substrates. The state-of-the-art new generation solar cell devices, such as transparent, flexible and light-weight solar cells, with MNWN as a transparent conductive electrode are emphasized. Finally, the opportunities and challenges for the development of MNWN electrodes toward application in the new generations of photovoltaic devices are discussed.

Keywords
Metal nanowire network, Transparent electrode, New-generation photovoltaic, Solar cell, Conductivity
National Category
Materials Chemistry Condensed Matter Physics
Identifiers
urn:nbn:se:uu:diva-395632 (URN)10.1016/j.mtener.2019.05.007 (DOI)000486148000016 ()
Funder
Swedish Energy AgencySwedish Research Council, 2017/192(182)StandUp
Available from: 2019-10-23 Created: 2019-10-23 Last updated: 2019-10-23Bibliographically approved
Zhang, X., Cappel, U. B., Jia, D., Zhou, Q., Du, J., Sloboda, T., . . . Johansson, E. (2019). Probing and Controlling Surface Passivation of PbS Quantum Dot Solid for Improved Performance of Infrared Absorbing Solar Cells. Chemistry of Materials, 31(11), 4081-4091
Open this publication in new window or tab >>Probing and Controlling Surface Passivation of PbS Quantum Dot Solid for Improved Performance of Infrared Absorbing Solar Cells
Show others...
2019 (English)In: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 31, no 11, p. 4081-4091Article in journal (Refereed) Published
Abstract [en]

Surface properties of colloidal quantum dots (CQDs) are critical for the transportation and recombination of the photoinduced charge carrier in CQD solar cells, therefore dominating the photovoltaic performance. Herein, PbS CQD passivated using liquid-state ligand exchange (LSLX) and solid-state ligand exchange (SSLX) strategies are in detail investigated using photoelectron spectroscopy (PES), and solar cell devices are prepared to understand the link between the CQD surface properties and the solar cell function. PES using different energies in the soft and hard Xray regime is applied to study the surface and bulk properties of the CQDs, and the results show more effective surface passivation of the CQDs prepared with the LSLX strategy and less formation of lead-oxide. The CQD solar cells prepared with LSLX strategy show higher performance, and the photoelectric measurements suggest that the recombination of photoinduced charges is reduced for the solar cell prepared with the LSLX approach. Meanwhile, the fabricated solar cells exhibit good stability. This work provides important insights into how to fine-tune the CQD surface properties by improving the CQD passivation, and how this is linked to further improvements of the device photovoltaic performance.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Materials Chemistry Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-390215 (URN)10.1021/acs.chemmater.9b00742 (DOI)000471728200026 ()
Funder
Swedish Energy AgencySwedish Research Council FormasSwedish Research CouncilGöran Gustafsson Foundation for Research in Natural Sciences and MedicineStiftelsen Olle Engkvist ByggmästareÅForsk (Ångpanneföreningen's Foundation for Research and Development)
Available from: 2019-08-08 Created: 2019-08-08 Last updated: 2019-08-08Bibliographically approved
Karimipour, M., Bagheri, M., Johansson, E. & Molaei, M. (2018). Excellent growth of ZnS shell on Ag2S QDs using a photochemical-microwave irradiation approach and fabrication of their indoor QD thin film solar cells. Materials technology (New York, N.Y.), 33(12), 784-792
Open this publication in new window or tab >>Excellent growth of ZnS shell on Ag2S QDs using a photochemical-microwave irradiation approach and fabrication of their indoor QD thin film solar cells
2018 (English)In: Materials technology (New York, N.Y.), ISSN 1066-7857, E-ISSN 1753-5557, Vol. 33, no 12, p. 784-792Article in journal (Refereed) Published
Abstract [en]

In this report, a new two pots method using microwave-photochemical approaches was suggested for the fabrication of Ag2S@ZnS core-shells. UV-Vis and photoluminescence spectroscopies clearly proved the growth of ZnS shell on Ag2S cores. X-ray diffraction, Energy dispersive x-ray spectroscopy and transmission electron microscopy also indicated the formation of core-shell structure. To identify excellence growth of ZnS shell, Ag2S@ZnS core-shells were implemented for the fabrication of thin film solar cells. The fabricated cells showed a J-V character with 0.4%, 1 mA.cm(-2) and 0.43V and 54% as efficiency, J(SC), V-OC and fill factor, respectively. The cells showed also an increasing efficiency up to 0.8% upon the decrease of incident solar intensity to 10% of its standard. The results proved the cells are stable under sun light illumination that is promising for environmentally friendly fabrication of QD thin film solar cells.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2018
Keywords
Ag2S@ZnS core-shells, Photoluminescence, Solar cells, Photochemical synthesis, Microwave irradiation
National Category
Materials Chemistry Physical Chemistry
Identifiers
urn:nbn:se:uu:diva-364486 (URN)10.1080/10667857.2018.1503781 (DOI)000443904600003 ()
Available from: 2018-10-29 Created: 2018-10-29 Last updated: 2018-10-29Bibliographically approved
Yang, L., Schölin, R., Gabrielsson, E., Boschloo, G., Rensmo, H., Sun, L., . . . Johansson, E. M. J. (2018). Experimental and Theoretical Investigation of the Function of 4-tert-Butyl Pyridine for Interface Energy Level Adjustment in Efficient Solid-State Dye-Sensitized Solar Cells. ACS Applied Materials and Interfaces, 10(14), 11572-11579
Open this publication in new window or tab >>Experimental and Theoretical Investigation of the Function of 4-tert-Butyl Pyridine for Interface Energy Level Adjustment in Efficient Solid-State Dye-Sensitized Solar Cells
Show others...
2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 14, p. 11572-11579Article in journal (Refereed) Published
Abstract [en]

4-tert-Butylpyridine (t-BP) is commonly used in solid state dye-sensitized solar cells (ssDSSCs) to increase the photovoltaic performance. In this report, the mechanism how t-BP functions as a favorable additive is investigated comprehensively. ssDSSCs were prepared with different concentrations of t-BP, and a clear increase in efficiency was observed up to a maximum concentration and for higher concentrations the efficiency thereafter decreases. The energy level alignment in the complete devices was measured using hard X-ray photoelectron spectroscopy (HAXPES). The results show that the energy levels of titanium dioxide are shifted further away from the energy levels of spiro-OMeTAD as the t-BP concentration is increased. This explains the higher photovoltage obtained in the devices with higher t-BP concentration. In addition, the electron lifetime was measured for the devices and the electron lifetime was increased when adding t-BP, which can be explained by the recombination blocking effect at the surface of TiO2. The results from the HAXPES measurements agree with those obtained from density functional theory calculations and give an understanding of the mechanism for the improvement, which is an important step for the future development of solar cells including t-BP.

Keywords
mesoporous, TiO2, photovoltaic, dye, solar energy
National Category
Physical Chemistry Materials Chemistry
Identifiers
urn:nbn:se:uu:diva-353206 (URN)10.1021/acsami.7b16877 (DOI)000430156000021 ()29560716 (PubMedID)
Funder
Swedish Energy AgencySwedish Research CouncilSwedish Research Council FormasEU, FP7, Seventh Framework Programme, 226716
Available from: 2018-06-13 Created: 2018-06-13 Last updated: 2018-06-13Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9358-8277

Search in DiVA

Show all publications