Improved interfacial property by small molecule ethanediamine for high performance inverted planar perovskite solar cells

We report a simple and effective method to realize desirable interfacial property for inverted planar perovskite solar cells (PSCs) by using small molecule ethanediamine for the construction of a novel polyelectrolyte hole transport material (P3CT-ED HTM). It is found that P3CT-ED can not only improve the hole transport property of P3CT-K but also improve the crystallinity of adjacent perovskite film. In addition, the introduction of ethanediamine into P3CT realigns the conduction and valence bands upwards, passivates surface defects and reduces non-radiative recombination. As a consequence, compared to P3CT-K hole transport layer (HTL) based devices, the average power conversion efficiency (PCE) is boosted from 17.2% to 19.6% for the counterparts with P3CT-ED, with simultaneous enhancement in open circuit voltage and fill factor. The resultant device displays a champion PCE of 20.5% with negligible hysteresis. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.