Synthesis and luminescence of ZnMgS:Mn ²⁺ nanoparticles

Efficient green emission from ZnMgS:Mn ²⁺ nanoparticles prepared by co-doping Mg ²⁺ and Mn ²⁺ ions into ZnS lattices has been observed. The synthesis is carried out in aqueous solution, followed by a post-annealing process, thus showing the features of less complexity, low cost, and easy incorporation of dopants. In comparison with the emission of ZnS:Mn ²⁺ nanoparticles, which is located generally around 590 nm, the photoluminescence of ZnMgS:Mn ²⁺ nanoparticles is blue-shifted by 14 nm in wavelength, leading to the enhanced green emission. The X-ray diffraction, electron spin resonance, and pressure dependent photoluminescence measurements suggest that the change of the crystal field caused by Mg ²⁺ ionic doping and the lower symmetry in the nanoparticles may account for the blue-shift of the photoluminescence. The ZnMgS:Mn ²⁺ nanoparticles with 1% Mn ²⁺ doping exhibit the strongest luminescence, which could potentially meet the requirements for the construction of green light emitting diodes.