| 1. |
- Hultqvist, Adam, et al.
(författare)
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Atomic Layer Deposition of Electron Selective SnOx and ZnO Films on Mixed Halide Perovskite : Compatibility and Performance
- 2017
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 9:35, s. 29707-29716
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Tidskriftsartikel (refereegranskat)abstract
- The compatibility of atomic layer deposition directly onto the mixed halide perovskite formamidinium lead iodide:methylammonium lead bromide (CH(NH2)(2), CH3NH3)Pb(I,Br)(3) (FAPbI(3):MAPbBr(3)) perovskite films is investigated by exposing the perovskite films to the full or partial atomic layer deposition processes for the electron selective layer candidates ZnO and SnOx. Exposing the samples to the heat, the vacuum, and even the counter reactant of H2O of the atomic layer deposition processes does not appear to alter the perovskite films in terms of crystallinity, but the choice of metal precursor is found to be critical. The Zn precursor Zn(C2H5)(2) either by itself or in combination with H2O during the ZnO atomic layer deposition (ALD) process is found to enhance the decomposition of the bulk of the perovskite film into PbI2 without even forming ZnO. In contrast, the Sn precursor Sn(N(CH3)(2))(4) does not seem to degrade the bulk of the perovskite film, and conformal SnOx films can successfully be grown on top of it using atomic layer deposition. Using this SnOx film as the electron selective layer in inverted perovskite solar cells results in a lower power conversion efficiency of 3.4% than the 8.4% for the reference devices using phenyl-C-70-butyric acid methyl ester. However, the devices with SnOx show strong hysteresis and can be pushed to an efficiency of 7.8% after biasing treatments. Still, these cells lacks both open circuit voltage and fill factor compared to the references, especially when thicker SnOx films are used. Upon further investigation, a possible cause of these losses could be that the perovskite/SnOx interface is not ideal and more specifically found to be rich in Sn, O, and halides, which is probably a result of the nucleation during the SnOx growth and which might introduce barriers or alter the band alignment for the transport of charge carriers.
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| 2. |
- Saki, Zahra, et al.
(författare)
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The Effect of Lithium Doping in Solution-Processed Nickel Oxide Films for Perovskite Solar Cells
- 2019
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Ingår i: ChemPhysChem. - : WILEY-V C H VERLAG GMBH. - 1439-4235 .- 1439-7641. ; 20:24, s. 3322-3327
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Tidskriftsartikel (refereegranskat)abstract
- The effect of substitutional Li doping into NiOx hole transporting layer (HTL) for use in inverted perovskite solar cells was systematically studied. Li doped NiOx thin films with preferential crystal growth along the (111) plane were deposited using a simple solution-based process. Mott-Schottky analysis showed that hole carrier concentration (N-A) is doubled by Li doping. Utilizing 4 % Li in NiOx improved the power conversion efficiency (PCE) of solar devices from 9.0 % to 12.6 %. Photoluminescence quenching investigations demonstrate better hole capturing properties of Li:NiOx compared to that of NiOx, leading to higher current densities by Li doping. The electrical conductivity of NiOx is improved by Li doping. Further improvements of the device were made by using an additional ZnO layer onto PCBM, to remove shunt paths, leading to a PCE of 14.2 % and a fill factor of 0.72.
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| 3. |
- Saki, Zahra, et al.
(författare)
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The synergistic effect of dimethyl sulfoxide vapor treatment and C-60 electron transporting layer towards enhancing current collection in mixed-ion inverted perovskite solar cells
- 2018
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Ingår i: Journal of Power Sources. - : ELSEVIER SCIENCE BV. - 0378-7753 .- 1873-2755. ; 405, s. 70-79
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Tidskriftsartikel (refereegranskat)abstract
- Inverted perovskite solar cells (PSCs) have been introduced as better candidate for roll-to-roll printing and scaleup than their conventional configuration counterparts, while their fabrication is technically more demanding. The common light absorbing layer in inverted PSCs is the single cation methylammonium lead iodide (MAPbI(3)) perovskite, whereas mixed-ion perovskites are chemically more stable. In mixed-ion perovskites, where FA (formamidinium) is the main replacement for MA, the electron affinity is larger than in MAPbI3 perovskites, leading to possible barriers against photoelectron collection by the electron transporting layer (ETL). In this paper we report on a mixed-ion (FAPbI(3))(0.83)(MAPbBr(3))(0.17) inverted PSC with improved photocurrent through using a dimethyl sulfoxide vapor treatment of perovskite layer and replacing the conventional [6,6]-phenyl-C-71 butyric acid methyl ester (PC70BM) with C-60/bathocuproine (BCP) as more effective ETL. The treatment of perovskite layer results in reduction of impurity phases of 8-FAPbI(3) and Pbl(2). Photoluminescence and open circuit voltage decay data demonstrate better charge carrier collection by the C-60/BCP compared to the PC70BM ETL, and an electron barrier for the back flow of electrons from ETL to perovskite. Our improvements in perovskite crystalization and electron transfer layer simultaneously lead to increasing the current density from 10 to 21 mA cm(-2).
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| 4. |
- Sveinbjornsson, Kari, et al.
(författare)
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Preparation of mixed-ion and inorganic perovskite films using water and isopropanol as solvents for solar cell applications
- 2018
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Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 2:3, s. 606-615
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Tidskriftsartikel (refereegranskat)abstract
- Presently, the most efficient lead halide perovskite solar cells are manufactured by using high-boiling point organic solvents to dissolve the perovskite precursor materials prior to the perovskite formation. Previously, efforts have been made to exchange the said solvents for water with some success. Herein, we build on that work to develop a procedure for synthesising perovskite absorbers using only water and isopropanol as solvents. Our technique can be utilised for fabricating many different perovskite compositions, organic and inorganic. The technique is based on the high solubility of metal nitrates, such as lead(ii) nitrate and caesium(i) nitrate, in water and, respectively, their poor solubilities in isopropanol. The inclusion of CsNO3 to Pb(NO3)(2) films does not result in a phase separation of the perovskite material as one would expect when using lead(ii) halide precursor films. Using the perovskite composition Cs(0.1)FA(0.9)Pb(I0.83Br0.17)(3) we were able to reach an average solar cell power conversion efficiency of 13.0%. Furthermore, the technique can be applied to many different perovskite compositions making it appealing for large-scale manufacturing of perovskite solar cells.
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| 5. |
- Sveinbjörnsson, Kári, et al.
(författare)
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Preparation of mixed-ion and inorganic perovskite films using water and isopropanol as solvents for solar cell applications
- 2018
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Ingår i: Sustainable Energy & Fuels. - : The Royal Society of Chemistry. - 2398-4902. ; 2:3, s. 606-615
-
Tidskriftsartikel (refereegranskat)abstract
- Presently, the most efficient lead halide perovskite solar cells are manufactured by using high-boiling point organic solvents to dissolve the perovskite precursor materials prior to the perovskite formation. Previously, efforts have been made to exchange the said solvents for water with some success. Herein, we build on that work to develop a procedure for synthesising perovskite absorbers using only water and isopropanol as solvents. Our technique can be utilised for fabricating many different perovskite compositions, organic and inorganic. The technique is based on the high solubility of metal nitrates, such as lead(ii) nitrate and caesium(i) nitrate, in water and, respectively, their poor solubilities in isopropanol. The inclusion of CsNO3 to Pb(NO3)2 films does not result in a phase separation of the perovskite material as one would expect when using lead(ii) halide precursor films. Using the perovskite composition Cs0.1FA0.9Pb(I0.83Br0.17)3 we were able to reach an average solar cell power conversion efficiency of 13.0%. Furthermore, the technique can be applied to many different perovskite compositions making it appealing for large-scale manufacturing of perovskite solar cells.
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