High Pressure Optical and Photoelectrical Studies

The effect of high pressures to 40 kilobars and temperatures down to 100(DEGREES)K on the intensity and lifetime of NaCl:Tl('+) and NaCl:In('+) has been studied. A kinetic model describing these phosphors has been presented. The excited ('3)T(,lu) state is radiatively and nonradiatively coupled to the ground state, ('3)A(,lg). The radiative rate increases with increasing pressure due to an increase of the spin orbit coupling. The nonradiative rate is not pressure sensitive. The ('3)T(,lu) state is in thermal equilibrium with the ('3)A(,lu) level below it. For NaCl:Tl('+) the energy separating the minima of the ('3)T(,lu) and ('3)A(,lu) was found to be 22.7 meV and was too small to be measured for NaCl:In. Pressure did not effect the thermal energy difference. It was found that the nonradiative rate, k(,nrT), increased with decreasing temperature decreasing the quantum yield.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Littman, Jon Eric

• Chemistry, Physical

Identifier

(UMI)AAI8302922

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70199