Phosphorus co-doping effect on photoluminescence in Ce 3+-doped SiO 2 glasses: The formation of unique ligand field by P-co-doping

Abstract

The origin of photoluminescence (PL) having UV emission from Ce 3+ ions in P 5+-co-doped SiO 2 glasses was studied through the elucidation of the coordination structure around a Ce 3+ by pulsed-EPR electron spin echo envelope modulatlion (ESEEM) spectroscopy. Simulation of the observed ESEEM pattern revealed that the number of P 5+ in the coordination sphere is ∼10 times larger than that estimated from the random distribution of P 5+, demonstrating the formation of a solvation shell structure. There are two types of the coordination manner of P–O bonds in the solvation structure, corner sharing and edge sharing. This solvation is close to that in phosphate glasses, giving a weak ligand field around Ce 3+ ions, i.e., the peak position and the lifetime of Ce 3+ ion move to a shorter side compared with the P-free SiO 2 glass.