Luminescence properties from erbium oxide nanocrystals dispersed in titania/organically modified silane composite sol-gel thin films

Luminescence properties from erbium (III) oxide nanocrystals dispersed in t itania/organically modified silane composite thin films were studied. Erbiu m oxide nanocrystals were prepared by an inverse microemulsion technique. A strong room-temperature photoluminescence was observed at 1.531 mum, with the full width at half maximum (FWHM) of 22 mn due to intra-atomic transiti ons between I-4(13/2) and I-4(15/2) levels in the erbium (III) ion. The sha pe, peak position, and FWHM of the photoluminescence signals from the compo site thin films were quite comparable to those prepared by other methods. T he photoluminescence peak of the composite thin films showed a maximum inte nsity at the heat-treatment temperature of 300 degreesC. A room-temperature green up-conversion emission at 543 nm (S-4(3/2) --> I-4(15/2) was observe d for the composite thin films with different heattreatment temperatures up on excitation at 993 nm. The upconversion emission mechanism was explained by means of an energy-level diagram and the lifetime of the visible upconve rsion emission was measured.