Realizing Tunable White Light Emission in Lead-Free Indium(III) Bromine Hybrid Single Crystals through Antimony(III) Cation Doping

Low-dimensional
metal halide hybrids (OIMHs) have recently been
explored as single-component white-light emitters for use in solid-state
lighting. However, it still remains challenging to realize tunable
white-light emission in lead-free zero-dimensional (0D) hybrid system.
Here, a combination strategy has been proposed through doping Sb3+ enabling and balancing multiple emission centers toward
the multiband warm white light. We first synthesized a new lead-free
0D (C8NH12)6InBr9·H2O single crystal, in which isolated [InBr6]3– octahedral units are separated by large organic cations
[C8NH12]+. (C8NH12)6­InBr9·H2O exhibits
dual-band emissions with one intense cyan emission and a weak red
emission tail. The low-energy ultrabroadband red emission tail can
be greatly enhanced by the Sb3+ doping. Experimental data
and first-principles calculations reveal that the original dominant
cyan emission is originated from the organic cations [C8NH12]+ and that the broadband red emission
is ascribed to self-trapped excitons in [In­(Sb)­Br6]3–. When the Sb concentration is 0.1%, a single-component
warm white-light emission with a photoluminescence quantum efficiency
of 23.36%, correlated color temperature of 3347 K, and a color rendering
index up to 84 can be achieved. This work represents a significant
step toward the realization of single-component white-light emissions
in environmental-friendly, high-performance 0D metal halide light-emitting
materials.