TY  - JOUR
A1  - Lang, Felix
A1  - Köhnen, Eike
A1  - Warby, Jonathan
A1  - Xu, Ke
A1  - Grischek, Max
A1  - Wagner, Philipp
A1  - Neher, Dieter
A1  - Korte, Lars
A1  - Albrecht, Steve
A1  - Stolterfoht, Martin
T1  - Revealing fundamental efficiency limits of monolithic perovskite/silicon tandem photovoltaics through subcell characterization
JF  - ACS Energy Letters
N2  - Perovskite/silicon tandem photovoltaics (PVs) promise to accelerate the decarbonization of our energy systems. Here, we present a thorough subcell diagnosis methodology to reveal deep insights into the practical efficiency limitations of state-of-the-art perovskite/silicon tandem PVs. Our subcell selective intensity-dependent photoluminescence (PL) and injection-dependent electroluminescence (EL) measurements allow independent assessment of pseudo-V-OC and power conversion efficiencies (PCEs) for both subcells. We reveal identical metrics from PL and EL, which implies well-aligned energy levels throughout the entire cell. Relatively large ideality factors and insufficient charge extraction, however, cause each a fill factor penalty of about 6% (absolute). Using partial device stacks, we then identify significant losses in standard perovskite subcells due to bulk and interfacial recombination. Lastly, we present strategies to minimize these losses using triple halide (CsFAPb(IBrCI)(3)) based perovskites. Our results give helpful feedback for device development and lay the foundation toward advanced perovskite/silicon tandem PVs capable of exceeding 33% PCE.
Y1  - 2021
U6  - https://doi.org/10.1021/acsenergylett.1c01783
SN  - 2380-8195
VL  - 6
IS  - 11
SP  - 3982
EP  - 3991
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Zu, Fengshuo
A1  - Warby, Jonathan
A1  - Stolterfoht, Martin
A1  - Li, Jinzhao
A1  - Shin, Dongguen
A1  - Unger, Eva
A1  - Koch, Norbert
T1  - Photoinduced energy-level realignment at interfaces between organic semiconductors and metal-halide perovskites
JF  - Physical review letters
N2  - In contrast to the common conception that the interfacial energy-level alignment is affixed once the interface is formed, we demonstrate that heterojunctions between organic semiconductors and metal-halide perovskites exhibit huge energy-level realignment during photoexcitation. Importantly, the photoinduced level shifts occur in the organic component, including the first molecular layer in direct contact with the perovskite. This is caused by charge-carrier accumulation within the organic semiconductor under illumination and the weak electronic coupling between the junction components.
Y1  - 2021
U6  - https://doi.org/10.1103/PhysRevLett.127.246401
SN  - 0031-9007
SN  - 1079-7114
VL  - 127
IS  - 24
PB  - American Physical Society
CY  - College Park
ER  -