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

A comprehensive photoluminescence and mechanoluminescence analysis ofZnS:Mn2+ nano-phosphor with zinc blende structure is presented. The samplecontaining quantum dot-sized nanocrystallites were synthesized by the chemicalprecipitation method and shows excellent orange luminescence at ambientconditions related to the 4T1->6A1 transition. The sample shows stable andidentical luminescence behavior under both UV and X-ray excitation at ambientconditions and also shows excellent self-powered mechanoluminescenceproperties. The pressure and temperature-induced luminescence mechanism of thephosphor is also established. The shift of the 4T1->6A1 luminescence band ofMn2+ with both pressure and temperature and the luminescence mechanism isexplained via the d5 Tanabe Sugano diagram. The broad luminescence band of4T1->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 quenchedcompletely at a pressure of 16.41 GPa due to a reversible phase transition fromzinc blende to rocksalt phase. The high-pressure and temperature-dependentdecay kinetics measurements of the sample luminescence are also reported.