Temperature and Pressure Dependent Luminescence Mechanism of Zinc-Blende Structured ZnS:Mn Nanophosphor under UV and X-ray Excitations

Abstract: A comprehensive photoluminescence and mechanoluminescence analysis of ZnS:Mn2+ nano-phosphor with zinc blende structure is presented. The sample containing quantum dot-sized nanocrystallites were synthesized by the chemical precipitation method and shows excellent orange luminescence at ambient conditions related to the 4T1->6A1 transition. The sample shows stable and identical luminescence behavior under both UV and X-ray excitation at ambient conditions and also shows excellent self-powered mechanoluminescence properties. The pressure and temperature-induced luminescence mechanism of the phosphor is also established. The shift of the 4T1->6A1 luminescence band of Mn2+ with both pressure and temperature and the luminescence mechanism is explained via the d5 Tanabe Sugano diagram. The broad luminescence band of 4T1->6A1 transition shifts from visible to near-infrared range at a rate of -35.8 meV/GPa with the increase of pressure and it is subsequently quenched completely at a pressure of 16.41 GPa due to a reversible phase transition from zinc blende to rocksalt phase. The high-pressure and temperature-dependent decay kinetics measurements of the sample luminescence are also reported.