The performance of three-dimensional (3D) organic-inorganic halide perovskite solar cells (PSCs) can be enhanced by surface treatment with 2D layered perovskites with efficient charge transport.

       Kai Zhu et al recently published a study in Science. The research team maximized hole transport between layers of a metastable Dion-Jacobson (DJ) two-dimensional perovskite that tunes the alignment of asymmetric bulky organic molecules. The reduction of the energy barrier for hole transport resulted in a 4- to 5-fold increase in the out-of-plane transport rate and a power conversion efficiency (PCE) of 4.9% in 2D PSCs. With the help of the metastable DJ 2D surface layer, the PCEs of three common 3D PSCs are improved by about 12% to 16%, reaching about 24.7%. For a triple-cation–mixed-halide PSC, 90% of the initial PCE was retained after 1000 hours of 1-sun operation at ~40°C in nitrogen.