Stable and High-Efficiency Perovskite Solar Cells Using Effective Additive Ytterbium Fluoride

With better light utilization, larger tolerance factor, and higher power conversion efficiency (PCE), the HC(NH2)(2)(+)(FA)-based perovskite is proven superior to the popular CH3NH3+ (MA)- and Cs-based halide perovskites in solar cell applications. Unfortunately, limited by intrinsic defects within the FA-based perovskite films, the perovskite films can be easily transformed into a yellow & delta;-phase at room temperature in the fabrication process, a troublesome challenge for its further development. Here, ytterbium fluoride (YbF3) is introduced into the perovskite precursor for three objectives. First of all, the partial substitution of Yb3+ for Pb2+ in the perovskite lattice increases the tolerance factor of the perovskite lattice and facilitates the formation of the & alpha; phase. Second, YbF3 and DMSO in the solvent form a Lewis acid complex YbF3 & BULL;DMSO, which can passivate the perovskite film, reduce defects, and improve device stability. Consequently, the YbF3 modified Perovskite solar cell exhibits a champion conversion efficiency of 24.53% and still maintains 90% of its initial efficiency after 60 days of air exposure under 30% relative humidity.

Automated summary

Compared to the traditional CH3NH3+ (MA) and Cs-based halide perovskites, the HC(NH2)(2)(+)(FA)-based perovskite has better light utilization, larger tolerance factor, and higher power conversion efficiency in solar cell applications. However, the intrinsic defects within FA-based perovskite films limit their further development as the films can easily transform into a yellow & delta;-phase at room temperature during the fabrication process.