TY  - JOUR
A1  - Grischek, Max
A1  - Caprioglio, Pietro
A1  - Zhang, Jiahuan
A1  - Pena-Camargo, Francisco
A1  - Sveinbjornsson, Kari
A1  - Zu, Fengshuo
A1  - Menzel, Dorothee
A1  - Warby, Jonathan H.
A1  - Li, Jinzhao
A1  - Koch, Norbert
A1  - Unger, Eva
A1  - Korte, Lars
A1  - Neher, Dieter
A1  - Stolterfoht, Martin
A1  - Albrecht, Steve
T1  - Efficiency Potential and Voltage Loss of Inorganic CsPbI2Br Perovskite Solar Cells
JF  - Solar RRL
N2  - Inorganic perovskite solar cells show excellent thermal stability, but the reported power conversion efficiencies are still lower than for organic-inorganic perovskites. This is mainly caused by lower open-circuit voltages (V(OC)s). Herein, the reasons for the low V-OC in inorganic CsPbI2Br perovskite solar cells are investigated. Intensity-dependent photoluminescence measurements for different layer stacks reveal that n-i-p and p-i-n CsPbI2Br solar cells exhibit a strong mismatch between quasi-Fermi level splitting (QFLS) and V-OC. Specifically, the CsPbI2Br p-i-n perovskite solar cell has a QFLS-e center dot V-OC mismatch of 179 meV, compared with 11 meV for a reference cell with an organic-inorganic perovskite of similar bandgap. On the other hand, this study shows that the CsPbI2Br films with a bandgap of 1.9 eV have a very low defect density, resulting in an efficiency potential of 20.3% with a MeO-2PACz hole-transporting layer and 20.8% on compact TiO2. Using ultraviolet photoelectron spectroscopy measurements, energy level misalignment is identified as a possible reason for the QFLS-e center dot V-OC mismatch and strategies for overcoming this V-OC limitation are discussed. This work highlights the need to control the interfacial energetics in inorganic perovskite solar cells, but also gives promise for high efficiencies once this issue is resolved.
KW  - CsPbI2Br
KW  - efficiency potentials
KW  - inorganic perovskites
KW  - photoluminescence
KW  - solar cells
KW  - voltage losses
Y1  - 2022
U6  - https://doi.org/10.1002/solr.202200690
SN  - 2367-198X
VL  - 6
IS  - 11
PB  - Wiley-VCH
CY  - Weinheim
ER  -