CH₃NH₃PbBr₃ Quantum Dot-Induced Nucleation for High Performance Perovskite Light-Emitting Solar Cells

Solution-processed organometallic halide perovskites have obtained rapid development for light-emitting diodes (LEDs) and solar cells (SCs). These devices are fabricated with similar materials and architectures, leading to the emergence of perovskite-based light-emitting solar cells (LESCs). The high quality perovskite layer with reduced nonradiative recombination is crucial for achieving a high performance device, even though the carrier behaviors are fundamentally different in both functions. Here CH₃NH₃PbBr₃ quantum dots (QDs) are first introduced into the antisolvent in solution phase, serving as nucleation centers and inducing the growth of CH₃NH₃PbI₃ films. The heterogeneous nucleation based on high lattice matching and a low free-energy barrier significantly improves the crystallinity of CH₃NH₃PbI₃ films with decreased grain sizes, resulting in longer carrier lifetime and lower trap-state density in the films. Therefore, the LESCs based on the CH₃NH₃PbI₃ films with reduced recombination exhibit improved electroluminescence and external quantum efficiency. The current efficiency is enhanced by 1 order of magnitude as LEDs, and meanwhile the power conversion efficiency increases from 14.49% to 17.10% as SCs, compared to the reference device without QDs. Our study provides a feasible method to grow high quality perovskite films for high performance optoelectronic devices.