Effects of erbium oxalate content and temperature on green up-conversion luminescence of erbium oxalate nanoparticles/titania/ormosil composite thin films

Erbium(III) oxalate nanoparticles prepared by a microemulsion technique was dispersed into titania/organically modified silane (ormosil) composite sol-gel thin films derived at low temperature. An up-conversion processes of the composite thin film was studied and a relatively strong room temperature green up-conversion emission at 543 nm (⁴S_3/2 → ⁴I_15/2) was observed for the composite thin films with different erbium oxalate content and heat treatment temperature upon near infrared excitation wavelength of 993 nm. The lifetime of the green up-conversion emission was measured and the up-conversion emission mechanism was explained by means of an energy level diagram.