A Water-Stable Zero-Dimensional Organic–Inorganic Metal Halide Hybrid with White Light Emission for Solid-State Lighting

Organic–inorganic hybrid halide materials have emerged as promising candidates for advanced optoelectronic applications due to their unique structural and optical properties. In this study, we explored the photoluminescence (PL) properties, stability, and photophysical mechanism of [EMPA]2Pb3Br12 crystal, (EMPA = 5-((4-ethylpiperazin-1-yl)methyl)pyridin-2-amine). This zero-dimensional hybrid halide exhibits broad white-light emission with a high photoluminescence quantum yield of 19.0% and a high color rendering index (CRI) of 90. Temperature-dependent PL spectra reveal a dual-emission mechanism, where delocalized excitons dominate at room temperature, while self-trapped excitons contribute significantly at lower temperatures due to lattice relaxation and suppressed nonradiative decay. White-light-emitting diode devices fabricated using [EMPA]2Pb3Br12 as a phosphor achieve bright white light with CRI of 89. These findings highlight [EMPA]2Pb3Br12 as a promising candidate for next-generation solid-state lighting and display technologies, combining high performance with remarkable durability.