Crack-free perovskite layers for high performance and reproducible devices via improved control of ambient conditions during fabrication

Organic-inorganic perovskite has shown one of the most rapid growths ever in photovoltaic history and achieved remarkable achievement with PCE of 22.1%. Since the first perovskite solar cells (PSCs) was reported in 2009, it always existed a problem that the performance of PSCs prepared in winter is much better than summer due to films cracking. In this article, we explored the reasons for this phenomenon and provided a corresponding solution. It was found that film cracking was a major contributor for losses of PSCs performance. By adjusting ambient temperature of operating environment, the film quality and device performance can be increased effectively. Result showed that mirror-like perovskite film surface without cracks can be prepared by control operating environment, and the power conversion efficiency was boosted from 13% to values more than 18% measured under standard solar conditions (AM 1.5G,100 mW/cm(2)). Furthermore, this method exhibits good reproducibility. It is expected that by this effective approach and better understanding of the perovskite preparation process, high efficiency and reproducible PSCs device can be prepared. (C) 2017 Elsevier B.V. All rights reserved.