Ultraviolet Light-Emitting Diodes Based on Two-Dimensional Metal Halide Perovskites

Recent advances in perovskite light-emitting diodes (PeLEDs) position them as promising candidates for next-generation displays and lighting, covering the full visible spectrum and extending into the deep blue and violet regions. These materials offer a simpler fabrication process compared to conventional III-V semiconductors, avoiding the need for lattice-matching and enabling easy deposition of polycrystalline films without metal-organic chemical vapor deposition. However, achieving shorter emission wavelengths is challenging due to the larger bandgaps required, complicating electron-hole recombination dynamics necessary for efficient electroluminescence. This study addresses these challenges by fine-tuning the halide composition in two-dimensional perovskites, extending the bandgap to 3.1 eV, and achieving photoluminescent emission at 393 nm. Introducing an optimized dual electron transport layer architecture improves electron injection and hole confinement within the perovskite matrix, resulting in high-purity electroluminescent emission at 399 nm. This approach achieves a maximum external quantum efficiency of 0.16%, setting a new benchmark for PeLEDs in the ultraviolet wavelength range. These results underscore the potential of large bandgap perovskite materials for next-generation light-emitting applications.