Enhanced photoemission from nanoscale agglomerations in Li co-activated Y2O3:Eu3+ thin films

Nanostructured Y2O3:Eu3+ and Li+ co-activated Y2O3:Eu3+ thin film phosphors have been deposited on fused amorphous quartz, silicon (1 1 1) and alumina (0 0 0 1) substrates using reactive pulsed laser deposition technique. Crystal structure, morphology and optical properties of the films were studied using GIXRD, SEM, AFM, UV–vis and photoluminescence. X-ray diffraction investigations indicate that the structural properties of these films strongly depend on substrate temperature, oxygen partial pressure and Li+ co-activation. An increase in photoluminescence with deviation in lattice constant was observed for all the films. AFM images show nanoscale agglomerations in Li co-activated films, prepared at 873 K under an oxygen partial pressure of 0.002 mbar, and photoluminescence studies indicate intense photoemission from these films. Dependence of asymmetric ratio of the photoluminescence spectra of Li co-activated Y2O3:Eu3+ thin films on the substrate temperature and Li co-activation are reported. Using CIE chromaticity diagram, x chromaticity values are determined from the photoluminescence spectra of Y2O3:Eu3+ and Li co-activated Y2O3:Eu3+ thin films deposited at different substrate temperatures and is discussed.