Radiothermoluminescence in Tetracene-Doped and Hydrostatically Deformed Anthracene Crystals

Abstract

The mechanism of radiothermoluminescence was studied on anthracene crystals doped with small concentrations of tetracene and on crystals deformed by hydrostatic high pressures. The dependence of the glow intensity on the absorbed dose was determined for all the samples and their thermoluminescence spectra compared with those of fluorescence. In the case of doped crystals, lattice imperfections around tetracene molecules act as traps, and in the case of deformed crystals, imperfections caused by high pressure treatment act as traps. The energy migration occurs before trapping. The migration lengths are estimated by employing modified target theory at 200, 300, 400 and 800Å for 10⁻³, 10⁻⁴, 10⁻⁵ and 10⁻⁶ samples respectively. For tetracene-doped samples, the emission process after detrapping is similar to that of fluorescence excited by U-V light, and the thermoluminescence is emitted from tetracene molecules. For deformed samples, however, the emission sites are lattice imperfections, which have been induced by high pressures etc. around the traps.