Near-unity PLQY and high anti-thermal quenching red luminescence from one-dimensional hybrid manganese chloride for efficient and stable white light-emitting diodes

The discovery of novel Mn²⁺-based metal halides with excellent luminescence properties and thermostability is particularly of great importance for solid-state lighting (SSL). Herein, a novel one-dimensional hybrid manganese chloride (TMA)MnCl₃ of a hexagonal system with a P6₃/m space group is synthesized via a simple saturation crystallization method. Under 443 nm excitation, (TMA)MnCl₃ single crystals exhibit a strong broad-band red emission peak at 645 nm originating from the ⁴T₁ → ⁶A₁ transition of Mn²⁺ ions with a full width at half maximum of 99 nm and a photoluminescence quantum yield (PLQY) of 98.6%. Moreover, (TMA)MnCl₃ shows a high anti-thermal quenching behavior, and the integrated PL intensity still retains 100% of the initial intensity measured at 300 °C, caused by the high structural rigidity. Benefiting from its strong blue light excitation, high PLQY, and excellent thermal stability, a stable white light-emitting diode device is fabricated by combining a 465 nm blue LED chip, green-emitting Lu₃Al₅O₁₂:Ce³⁺ and the (TMA)MnCl₃ red phosphor with a high color rendering index of 94.3% and a correlated color temperature of 3995 K. This work develops a novel hybrid manganese chloride red-emitter and paves a new path to explore high-performance phosphors excited by blue light for SSL.