Highly stable air processed perovskite solar cells by interfacial layer engineering

Abstract

Perovskite solar cells (PSCs) have emerged as the most promising technology for third generation photovoltaics. However, despite a very recent report of power conversion efficiency values as high as 25.5%, the limited stability of PSCs is still a major concern. Here, PbS quantum dots (QDs) deposited by pulsed laser deposition on high quality mixed halide‐perovskite films, prepared in ambient air, are used to significantly improve the stability. We compare the stability of PSCs with and without the PbS-QDs, which is employed as a stand-alone hole transport layer and as an interfacial layer between the perovskite layer and the copper thiocyanate (CuSCN) film in the fabricated devices. Under continuous illumination with a solar simulator and over 30 days’ storage in ambient air, our best devices employing PbS-QDs as interfacial layer exhibit improved long term stability maintaining over 84% of the initial performance. Moreover, along with the improvement in efficiency, the hysteresis behavior also vanishes in devices made with PbS-QDs. Consequently, we demonstrate that PbS-QDs grown by physical vapor deposition, used for interfacial engineering in a hybrid PSCs, are promising towards improved performance in terms of extending their lifetime and suppressing the hysteretic behavior.