Over 20% PCE perovskite solar cells with superior stability achieved by novel and low-cost hole-transporting materials

Fei Zhang, Zhiqiang Wang, Hongwei Zhu, Norman Pellet, Jingshan Luo, Chenyi Yi, Xicheng Liu, Hongli Liu, Shirong Wang, Xianggao Lia, Yin Xiao, Shaik Mohammed Zakeeruddin, Dongqin Bi, Michael Grätzel

DOI: 10.1016/j.nanoen.2017.09.035.
First published online 19 Sep 2017
Paper on publisher's website
Paper in open access repository

The exploration of alternative low-cost molecular hole-transporting materials (HTMs) for both highly efficient and stable perovskite solar cells (PSCs) is a relatively new research area. Two novel HTMs using the thiophene core were designed and synthesized (Z25 and Z26). The perovskite solar cells based on Z26 exhibited a remarkable overall power conversion efficiency (PCE) of 20.1%, which is comparable to 20.6% obtained with spiroOMeTAD. Importantly, the devices based-on Z26 show better stability compared to devices based on Z25 and spiroOMeTAD when aged under ambient air of 30% or 85% relative humidity in the dark and under continuous full sun illumination at maximum power point tracking respectively. The presented results demonstrate a simple strategy by introducing double bonds to design hole-transporting materials for highly efficient and stable perovskite solar cells with low cost, which is important for commercial application.