All-inorganic 0D/3D Cs4Pb(IBr)6/CsPbI3−xBrx mixed-dimensional perovskite solar cells with enhanced efficiency and stability

Abstract

The inorganic halide perovskite CsPbI₃ has shown great promise in efficient solar cells. However, α-phase CsPbI₃ is thermodynamically unstable at room temperature, limiting its applications. Herein, we have successfully fabricated highly stable all-inorganic 0D/3D Cs₄Pb(IBr)₆/CsPbI_3−xBr_x mixed-dimensional perovskite solar cells. The 0D Cs₄Pb(IBr)₆ phase spontaneously distributes in the 3D CsPbI_3−xBr_x perovskite phase and facilitates the (100) preferential crystal orientation of the CsPbI_3−xBr_x crystals. Due to the reasonable energy level alignment and lattice match between (040) in 0D Cs₄Pb(IBr)₆ and (002) in 3D CsPbI_3−xBr_x crystals, a 0D–3D heterojunction structure formed. The defect passivation and non-radiative recombination suppression within the films effectively promote smooth carrier transport in the perovskite solar cells, boosting the efficiency to 14.77%. The devices retained 93.9% of the initial efficiency after 60 days in a nitrogen atmosphere. Moreover, a high efficiency of 10.52% has also been achieved in the 1 cm²-large solar cells due to the high uniformity and repeatability of the 0D/3D films.