TY  - JOUR
A1  - Stolterfoht, Martin
A1  - Caprioglio, Pietro
A1  - Wolff, Christian Michael
A1  - Marquez, Jose A.
A1  - Nordmann, Joleik
A1  - Zhang, Shanshan
A1  - Rothhardt, Daniel
A1  - Hörmann, Ulrich
A1  - Amir, Yohai
A1  - Redinger, Alex
A1  - Kegelmann, Lukas
A1  - Zu, Fengshuo
A1  - Albrecht, Steve
A1  - Koch, Norbert
A1  - Kirchartz, Thomas
A1  - Saliba, Michael
A1  - Unold, Thomas
A1  - Neher, Dieter
T1  - The impact of energy alignment and interfacial recombination on the internal and external open-circuit voltage of perovskite solar cells
JF  - Energy & environmental science
N2  - Charge transport layers (CTLs) are key components of diffusion controlled perovskite solar cells, however, they can induce additional non-radiative recombination pathways which limit the open circuit voltage (V-OC) of the cell. In order to realize the full thermodynamic potential of the perovskite absorber, both the electron and hole transport layer (ETL/HTL) need to be as selective as possible. By measuring the photoluminescence yield of perovskite/CTL heterojunctions, we quantify the non-radiative interfacial recombination currents in pin- and nip-type cells including high efficiency devices (21.4%). Our study comprises a wide range of commonly used CTLs, including various hole-transporting polymers, spiro-OMeTAD, metal oxides and fullerenes. We find that all studied CTLs limit the V-OC by inducing an additional non-radiative recombination current that is in most cases substantially larger than the loss in the neat perovskite and that the least-selective interface sets the upper limit for the V-OC of the device. Importantly, the V-OC equals the internal quasi-Fermi level splitting (QFLS) in the absorber layer only in high efficiency cells, while in poor performing devices, the V-OC is substantially lower than the QFLS. Using ultraviolet photoelectron spectroscopy and differential charging capacitance experiments we show that this is due to an energy level mis-alignment at the p-interface. The findings are corroborated by rigorous device simulations which outline important considerations to maximize the V-OC. This work highlights that the challenge to suppress non-radiative recombination losses in perovskite cells on their way to the radiative limit lies in proper energy level alignment and in suppression of defect recombination at the interfaces.
Y1  - 2019
U6  - https://doi.org/10.1039/c9ee02020a
SN  - 1754-5692
SN  - 1754-5706
VL  - 12
IS  - 9
SP  - 2778
EP  - 2788
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  - 
TY  - GEN
A1  - Saliba, Michael
A1  - Stolterfoht, Martin
A1  - Wolff, Christian Michael
A1  - Neher, Dieter
A1  - Abate, Antonio
T1  - Measuring aging stability of perovskite solar cells
T2  - Joule
Y1  - 2018
U6  - https://doi.org/10.1016/j.joule.2018.05.005
SN  - 2542-4351
VL  - 2
IS  - 6
SP  - 1019
EP  - 1024
PB  - Cell Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Saliba, Michael
A1  - Correa-Baena, Juan-Pablo
A1  - Wolff, Christian Michael
A1  - Stolterfoht, Martin
A1  - Phung, Thi Thuy Nga
A1  - Albrecht, Steve
A1  - Neher, Dieter
A1  - Abate, Antonio
T1  - How to Make over 20% Efficient Perovskite Solar Cells in Regular (n-i-p) and Inverted (p-i-n) Architectures
JF  - Chemistry of materials : a publication of the American Chemical Society
N2  - Perovskite solar cells (PSCs) are currently one of the most promising photovoltaic technologies for highly efficient and cost-effective solar energy production. In only a few years, an unprecedented progression of preparation procedures and material compositions delivered lab-scale devices that have now reached record power conversion efficiencies (PCEs) higher than 20%, competing with most established solar cell materials such as silicon, CIGS, and CdTe. However, despite a large number of researchers currently involved in this topic, only a few groups in the world can reproduce >20% efficiencies on a regular n-i-p architecture. In this work, we present detailed protocols for preparing PSCs in regular (n-i-p) and inverted (p-i-n) architectures with >= 20% PCE. We aim to provide a comprehensive, reproducible description of our device fabrication , protocols. We encourage the practice of reporting detailed and transparent protocols that can be more easily reproduced by other laboratories. A better reporting standard may, in turn, accelerate the development of perovskite solar cells and related research fields.
Y1  - 2018
U6  - https://doi.org/10.1021/acs.chemmater.8b00136
SN  - 0897-4756
SN  - 1520-5002
VL  - 30
IS  - 13
SP  - 4193
EP  - 4201
PB  - American Chemical Society
CY  - Washington
ER  -