TY  - JOUR
A1  - Zhang, Shanshan
A1  - Hosseini, Seyed Mehrdad
A1  - Gunder, Rene
A1  - Petsiuk, Andrei
A1  - Caprioglio, Pietro
A1  - Wolff, Christian Michael
A1  - Shoaee, Safa
A1  - Meredith, Paul
A1  - Schorr, Susan
A1  - Unold, Thomas
A1  - Burn, Paul L.
A1  - Neher, Dieter
A1  - Stolterfoht, Martin
T1  - The Role of Bulk and Interface Recombination in High-Efficiency Low-Dimensional Perovskite Solar Cells
JF  - Advanced materials
N2  - 2D Ruddlesden-Popper perovskite (RPP) solar cells have excellent environmental stability. However, the power conversion efficiency (PCE) of RPP cells remains inferior to 3D perovskite-based cells. Herein, 2D (CH3(CH2)(3)NH3)(2)(CH3NH3)(n-1)PbnI3n+1 perovskite cells with different numbers of [PbI6](4-) sheets (n = 2-4) are analyzed. Photoluminescence quantum yield (PLQY) measurements show that nonradiative open-circuit voltage (V-OC) losses outweigh radiative losses in materials with n > 2. The n = 3 and n = 4 films exhibit a higher PLQY than the standard 3D methylammonium lead iodide perovskite although this is accompanied by increased interfacial recombination at the top perovskite/C-60 interface. This tradeoff results in a similar PLQY in all devices, including the n = 2 system where the perovskite bulk dominates the recombination properties of the cell. In most cases the quasi-Fermi level splitting matches the device V-OC within 20 meV, which indicates minimal recombination losses at the metal contacts. The results show that poor charge transport rather than exciton dissociation is the primary reason for the reduction in fill factor of the RPP devices. Optimized n = 4 RPP solar cells had PCEs of 13% with significant potential for further improvements.
KW  - 2D perovskites
KW  - interface recombination
KW  - perovskite solar cells
KW  - photoluminescence
KW  - V-OC loss
Y1  - 2019
U6  - https://doi.org/10.1002/adma.201901090
SN  - 0935-9648
SN  - 1521-4095
VL  - 31
IS  - 30
PB  - Wiley-VCH
CY  - Weinheim
ER  -