Analysis of trap distribution of a red persistent luminescent materials using thermoluminescence.

Abstract

Trap distribution plays a crucial role in deciding the applicability of a material. The thermoluminescence (TL) parameter that describes trap distribution is η, which has never been discussed in TL analysis so far. TL analysis of a commercially available red persistent luminescent material (CaSrS:Eu) was performed using computerized glow curve deconvolution (CGCD) in the new general order kinetics. CGCD results showed that the red persistent luminescent material in the temperature range 300-600º K was comprised of nine peaks. Activation energy ranged from 0.66-1.27 eV. Frequency factor was in the range 109 to 1011 sec-1 . The major peaks of the red persistent luminescent material had lesser empty traps. The most important information provided by the analysis was that the major peaks of the red persistent luminescent material had 30-60% of the empty traps close to the filled traps, and this accounted for retrapping of thermally released electrons. This finding suggests that the occurrence of 30-60% empty traps close to the filled traps is a necessary requisite for a persistent luminescent material.