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