Structure and upconversion luminescence properties of Er3 +–Mo6 + codoped Yb2Ti2O7 films

Abstract Er 3 + –Mo 6 + codoped Yb 2 Ti 2 O 7 thin films have been prepared on Si(100) substrates by a sol–gel method and spin-coating technique. A well-defined face-centered cubic phase of Yb 2 Ti 2 O 7 was observed without the existence of either an Er or a Mo compound in Er 3 + –Mo 6 + codoped Yb 2 Ti 2 O 7 films. Mo 6 + codoping improved the morphology quality and increased the grain size of Er 3 + doped Yb 2 Ti 2 O 7 films. Compared with Er 3 + –Mo 6 + codoped Yb 2 Ti 2 O 7 powder, Er 3 + –Mo 6 + codoped Yb 2 Ti 2 O 7 films show different green and red upconversion emissions properties under 976 nm laser diode excitation. The Er 3 + –Mo 6 + codoped Yb 2 Ti 2 O 7 films showed higher luminescence intensity than the Er 3 + doped Yb 2 Ti 2 O 7 films, which was attributed to the transfer of high excited state energy from Yb 3 + –MoO 4 2 − dimers to Er 3 + .