Antimony-Triggered Tunable White Light Emission in Lead-Free Zero-Dimensional Indium Halide with Ultrastable CCT of White Light Emitting Diodes

A highly efficient and easily tunable luminescence is significant for solid-state luminescent (SSL) materials. However, achieving a photoluminescence quantum yield (PLQY) close to unity and tuning the emission remain challenging tasks. Metal doping strategies enable resolution of these issues. Herein, we report the preparation of a novel organic-inorganic lead-free indium-based metal halide hybrid <bold>(MP)</bold>(<bold>3</bold>)<bold>InCl</bold>(<bold>6</bold>)<bold>center dot EtOH</bold> (MP = C4H10ON) with a typical zero-dimension structure. When excited at 320 nm, <bold>(MP)</bold>(<bold>3</bold>)<bold>InCl</bold>(<bold>6</bold>)<bold>center dot EtOH</bold> exhibits a dual emission band at 420 and 600 nm, which originates from the organic cation [MP] and the [InCl6](3-) octahedral unit. The photoluminescence can be significantly enhanced through Sb3+ doping, resulting in an increase in PLQY from 0.78% to near unity. Multiple emission color tunings have been achieved by regulating the Sb doping level and the radiation wavelength, resulting in a change in emission color from blue -> white -> orange. Optical characterizations reveal that the significantly enhanced emission centered at 600 nm can be attributed to more efficient absorption, closely associated with an additional S-1(0) -> P-3(1) transition in the inorganic octahedron [In(Sb)Cl-6](3-) due to Sb3+ doping. With its excellent optical performance, a white light emitting diode (WLED) has been successfully fabricated by coating the mixture of <bold>(MP)</bold>(<bold>3</bold>)<bold>InCl</bold>(<bold>6</bold>)<bold>center dot EtOH:15%Sb3+</bold> with blue phosphor BaMgAl10O17:Eu2+ onto a UV LED chip. The WLED device exhibits perfect white light emission with regard to the International Commission on Illumination (CIE) coordinates of (0.36, 0.34). Significantly, the WLED device maintains a stable correlated color temperature (CCT) range of 4119-4393 K and CIE coordinates (x: 0.37-0.34, y: 0.35-0.33) as the driven current varies from 20 to 200 mA, demonstrating outstanding stability across different power levels. This work not only presents a novel system for achieving remarkably enhanced luminescent performance and tuning emission bands in 0D metal halides but also represents a significant step toward achieving resistance to color drifting for stable WLEDs.