Energy transfer between semiconductor nanoparticles (ZnS or CdS) and Eu3+ ions in sol-gel derived ZrO2 thin films

Semiconductor nanoparticles (CdS or ZnS) and Eu3+ co-doped zirconia thin films were prepared using the sol-gel route by an in situ method. We demonstrated that the energy exchange is more efficient between ZnS nanocrystals and Eu3+ ions than between CdS and Eu3+. The Eu3+ luminescence increased with the ion concentration up to 10 mol% (for 10 mol% ZnS). Moreover, the intensity of the europium emission increased as the ZnS nanoparticles concentration increased up to 15 mol% (for 5 mol% Eu3+). For The 15% ZnS-5% Eu3+ co-doped ZrO2 sample, the europium emissions were enhanced 42 times through energy transfer at 10 K. The defect states in semiconductor nanoparticles (CdS or ZnS) were found to play an important role in the energy transfer process.