Manganese halide hybrids with a reversible luminous color and their application for a white light-emitting diode

Organic–inorganic manganese halide hybrids have attracted attention in the field of light-emitting diodes (LEDs) due to their simple preparation, environmental friendliness and tunable luminescence. Herein, two manganese halide hybrids, (C5H8N2)2MnCl4 and C5H8N2(MnCl2)xCly, are synthesized by adopting different ratios of 1-ethylimidazole and MnCl2. (C5H8N2)2MnCl4 and C5H8N2(MnCl2)xCly show strong green and red emission with photoluminescence quantum yields (PLQYs) of up to 79.77% and 83.33%, respectively, which is attributed to the different coordination environments of Mn2+. The reversible conversion between red and green emission of C5H8N2(MnCl2)xCly coming from its decomposition and recovery makes it an interesting fluorescent material. Their applications in fabrication of a white LED (WLED) and a tunable color LED by combining with a blue GaN LED illustrate their great potential as effective phosphors for solid-state light-emission.