Review Stabilizing CsPbI3 perovskite for photovoltaic applications

With suitable band gap (Eg -1.7 eV), superb optoelectronic proper-ties, and thermal stability, CsPbI3 has been widely acknowledged as a competitive candidate for photovoltaic devices. However, the spontaneous phase transition to a non-perovskite phase limits its further application. Mighty efforts and advances have been made to stabilize the perovskite structure of CsPbI3 and improve power conversion efficiency of perovskite solar cells. In this review, we give insights regarding the origin of the instability of CsPbI3 from intrinsic assessment to external stimulation and review the strate-gies and progress to improve the stability of CsPbI3 perovskite structure and devices from the following aspects: (1) ionic incorpo-ration, (2) regulating surface energy, (3) incorporating low-dimen-sional perovskites, and (4) surface termination. Finally, we give a brief outlook on the challenges and opportunities of all-inorganic CsPbI3 perovskite.