Improved Performance of Er³⁺-Doped Double Perovskites/Si Light-Emitting Devices with Emission Wavelength at 1.55 μm

Metal halide perovskites exhibit excellent optical performance for light emission; however, their emission is limited to the visible spectrum, which limits their utility for future optical telecommunications. Among them, lead-free double perovskites exhibit unique optical properties attributed to the presence of an abundant self-trapped exciton state that enables a unique application for optoelectronics. However, there has been no report on an electrically driven light-emitting device at 1.5 μm utilizing perovskites so far. Consequently, a rare-earth-based double perovskite was designed containing Laporte-forbidden 4f-4f transitions of Er³⁺, enabling the dual emission of visible and near-infrared light. Simultaneously, Sb doping is adopted to optimize the band structure of the double perovskite, thereby enhancing the near-infrared emission at 1.5 μm through broadened self-trapped excitons and phonon-exciton coupling processes. Owing to these optical performance improvements, Si-based Cs₂NaErCl₆:Sb³⁺ electroluminescent light-emitting devices (LEDs) are prepared, and the near-infrared signal at about 1.5 μm is detected successfully. Furthermore, a passivation layer was incorporated into the Cs₂NaErCl₆:Sb³⁺ LEDs to passivate the defect between Cs₂NaErCl₆: Sb³⁺/ZnO interface. Owing to the reduction in carrier loss, the champion external quantum efficiency and output power density of this device significantly improved, reaching 2.4% and 5.98 mW cm^-2 respectively. These results represent pioneering advancements in Si-based perovskite LEDs and optical interconnection technology.