A simple in situ tubular chemical vapor deposition processing of large-scale efficient perovskite solar cells and the research on their novel roll-over phenomenon in J–V curves

Abstract

Hybrid perovskite solar cells (PSCs) with excellent photoelectric properties have attracted tremendous attention in recent years. However, the current thermal evaporation technology and solution-based route are still challenging to produce low-cost, large-scale, and uniform perovskite absorbers. Herein, we present a simple in situ tubular chemical vapor deposition (ITCVD) method to fabricate perovskite films. And initial results on the demonstrated sample with a size of 4 cm × 4 cm show potential for large area deposition by ITCVD. Meanwhile, the prepared CH₃NH₃PbI₃ films have an orthorhombic perovskite structure, exhibit a high crystallinity, and show outstanding optical properties. Accordingly, a high efficiency of 12.2% is also successfully achieved based on our first batch of planar type PSCs. More intriguingly, the novel roll-over phenomenon in J–V curves of PSCs is first investigated in this study, and further research proves that it is caused by the recently discovered PbI₂/CH₃NH₃PbI₃ heterojunction, which can help us to further understand the fundamental working mechanism of PSCs.