A-Site Rubidium Cation-Incorporated CsPbI_2Br All-Inorganic Perovskite Solar Cells Exceeding 17% Efficiency

摘要

Due to its excellent thermal stability and high performance, inorganic cesium leadmixed halide (ABX3, where A ¼ Cs, B = Pb, and X = I/Br) all-inorganic perovskitesolar cells (IPVSCs) have attracted much interest in optoelectronic applications.However, the film quality, enough absorption by desired film thickness, andnature of partial replacement of cations determine the stability of the CsPbI2Brperovskite films. Herein, a hot air method is used to control the thickness andmorphology of the CsPbI_2Br perovskite thin film, and the A-site (herein, Cs~+)cation is partially incorporated by rubidium (Rb~+) cations for making thestable black phase under ambient conditions. The Rb cation-incorporatedCs_(1-x)Rb_xPbI_2Br (x = 0–0.03) perovskite thin films exhibit high crystallinity,uniform grains, extremely dense, and pinhole-free morphology. The fabricateddevice with its Cs0.99Rb0.01PbI_2Br perovskite composition with poly(3-hexylthiophene-2,5-diyl) as a hole-transporting layer exhibits a power conversion efficiency(PCE) of 17.16%, which is much higher than that of CsPbI_2Br-basedIPVSCs. The fabricated Cs0.99Rb0.01PbI2Br-based IPVSC devices retain >90% ofthe initial efficiency over 120 h at 65 °C thermal stress, which is much higher thanthat of CsPbI_2Br samples.