Pseudohalide (SCN−)-doped CsPbI3 for high-performance solar cells

Abstract

Cesium lead halide CsPbI₃ is regarded as a promising material to solve the issues of material decomposition and ion migration caused by the organic group in organic–inorganic hybrid perovskite solar cells (PSCs) under operating conditions. However, there are many defects in a pure CsPbI₃ material and its cubic phase (α-phase) is thermodynamically unstable, which will prevent a high device performance. Here, we incorporated the pseudohalide ion SCN⁻ in a CsPbI₃ thin film to improve the crystallinity with smooth perovskite films. The results of XRD and PL showed that the crystallization property of the CsPbI₃ thin films with the addition of Pb(SCN)₂ exhibited a huge improvement compared to the reference. The champion power conversion efficiency (PCE) of CsPbI₃ PSCs with the optimized Pb(SCN)₂ additive (2%) could reach as high as 17.04%. In addition, the CsPbI₃ films with the Pb(SCN)₂ additive exhibited higher thermal stability than the reference one.