Temperature and pressure dependent luminescence mechanism of a zinc blende structured ZnS:Mn nanophosphor under UV excitation

Abstract

A comprehensive photoluminescence and mechanoluminescence analysis of a ZnS:Mn²⁺ nano-phosphor with a zinc blende structure is presented. The sample containing quantum dot-sized nanocrystallites was 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 exhibits 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 the ⁴T₁ → ⁶A₁ transition shifts from the visible to near-infrared range at a rate of −35.8 meV GPa⁻¹ with the increase of the pressure and it is subsequently quenched completely at a pressure of 16.41 GPa due to a reversible phase transition from zinc blende (F3m) to rocksalt (Fmm) phase. The high-pressure and temperature-dependent decay kinetics measurements of the sample luminescence are also reported.