Nature of Vn+ ions in SnO2: EPR and photoluminescence studies

SnO2 and 5 at.% V doped SnO2 samples were prepared by citrate-gel method. From Raman study on vanadium doped SnO2, the existence of phase separated V2O5 clusters has been established. EPR study on the V doped sample clearly revealed the existence of V4+ ions, which are incorporated in SnO2 lattice and the existence of conduction electrons with g = 1.993. For vanadium doped SnO2 sample, there is a decrease in luminescence at 400 nm and an increase in activation energy of electrical conduction compared to undoped SnO2, and this has been attributed to the decrease in oxygen vacancies brought about by the incorporation of V5+ in the SnO2 lattice.