Efficiency-Tunable Single-Component White-Light Emission Realized in Hybrid Halides Through Metal Co-Occupation

Organic–inorganic
hybrid metal halides have attracted widespread
attention as emerging optoelectronic materials, especially in solid-state
lighting, where they can be used as single-component white-light phosphors
for white light-emitting diodes. Herein, we have successfully synthesized
a zero-dimensional (0D) organic–inorganic hybrid mixed-metal
halide (Bmpip)2PbxSn1–xBr4 (0 < x < 1,
Bmpip+ = 1-butyl-1-methyl-piperidinium, C10H22N+) that crystallizes in a monoclinic system in
the C2/c space group. Pb2+ and Sn2+ form a four-coordinate seesaw structure separated
by organic cations forming a 0D structure. For different excitation
wavelengths, (Bmpip)2PbxSn1–xBr4 (0 < x < 1) exhibits double-peaked emission at 470 and 670 nm. The emission
color of (Bmpip)2PbxSn1–xBr4 can be easily tuned
from orange-red to blue by adjusting the Pb/Sn molar ratio or excitation
wavelength. Representatively, (Bmpip)2Pb0.16Sn0.84Br4 exhibits approximately white-light
emission with high photoluminescence quantum yield up to 39%. Interestingly,
the color of (Bmpip)2PbxSn1–xBr4 can also be easily
tuned by temperature, promising its potential for application in temperature
measurement and indication. Phosphor-converted light-emitting diodes
are fabricated by combining (Bmpip)2PbxSn1–xBr4 and
365 nm near-UV LED chips and exhibit high-quality light output.