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Reduced Interface‐Mediated Recombination for High Open‐Circuit Voltages in CH 3 NH 3 PbI 3 Solar Cells
Author(s) -
Wolff Christian M.,
Zu Fengshuo,
Paulke Andreas,
Toro Lorena Perdigón,
Koch Norbert,
Neher Dieter
Publication year - 2017
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201700159
Subject(s) - perovskite (structure) , materials science , energy conversion efficiency , fullerene , recombination , open circuit voltage , active layer , layer (electronics) , photoactive layer , optoelectronics , electron , analytical chemistry (journal) , voltage , polymer solar cell , nanotechnology , crystallography , chemistry , organic chemistry , physics , biochemistry , quantum mechanics , gene , thin film transistor
Perovskite solar cells with all‐organic transport layers exhibit efficiencies rivaling their counterparts that employ inorganic transport layers, while avoiding high‐temperature processing. Herein, it is investigated how the choice of the fullerene derivative employed in the electron‐transporting layer of inverted perovskite cells affects the open‐circuit voltage ( V OC ). It is shown that nonradiative recombination mediated by the electron‐transporting layer is the limiting factor for the V OC in the cells. By inserting an ultrathin layer of an insulating polymer between the active CH 3 NH 3 PbI 3 perovskite and the fullerene, an external radiative efficiency of up to 0.3%, a V OC as high as 1.16 V, and a power conversion efficiency of 19.4% are realized. The results show that the reduction of nonradiative recombination due to charge‐blocking at the perovskite/organic interface is more important than proper level alignment in the search for ideal selective contacts toward high V OC and efficiency.