Solution-Obtained (NH₄)₃In_0.95Sb_0.05Cl₆ with High External Photoluminescence Quantum Yield and Excellent...

The efficient broad-band emission from low-dimensional metal halides has garnered significant interest. However, most of these materials exhibit poor stability at the operating temperature of light-emitting diodes. In this study, using the solution method (temperature lower than 90 °C), a new compound (NH₄)₃In_0.95Sb_0.05Cl₆ was obtained with the structure in the Pnma space group featuring unit-cell parameters of a = 12.3871(4) Å, b = 24.9895(9) Å, and c = 7.7844(3) Å. (NH₄)₃In_0.95Sb_0.05Cl₆ can be prepared by doping (NH₄)₂InCl₅·H₂O when the Sb³⁺ feeding ratio is in the range of 30-80%. Thermal analysis reveals that (NH₄)₃In_0.95Sb_0.05Cl₆ is stable up to 320 °C. (NH₄)₃In_0.95Sb_0.05Cl₆ exhibits broad-band yellow-white emission with extremely high internal and external photoluminescence quantum yields of 93 and 77%, respectively. Interestingly, (NH₄)₃In_0.95Sb_0.05Cl₆ displays remarkable resistance to thermal quenching, retaining 83% of its initial photoluminescence intensity at 80 °C. A white light-emitting diode is fabricated by combining (NH₄)₃In_0.95Sb_0.05Cl₆ with a commercial phosphor, and a high color rendering of 92.8 was obtained. This work presents an environmentally friendly, efficient, stable UV-excited broad-band emission material for potential solid-state lighting applications.