Structure and upconversion luminescence properties of Er3Â +-Mo6Â + codoped Yb2Ti2O7 films

Er3 +-Mo6 + codoped Yb2Ti2O7 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 Yb2Ti2O7 was observed without the existence of either an Er or a Mo compound in Er3 +-Mo6 + codoped Yb2Ti2O7 films. Mo6 + codoping improved the morphology quality and increased the grain size of Er3 + doped Yb2Ti2O7 films. Compared with Er3 +-Mo6 + codoped Yb2Ti2O7 powder, Er3 +-Mo6 + codoped Yb2Ti2O7 films show different green and red upconversion emissions properties under 976 nm laser diode excitation. The Er3 +-Mo6 + codoped Yb2Ti2O7 films showed higher luminescence intensity than the Er3 + doped Yb2Ti2O7 films, which was attributed to the transfer of high excited state energy from Yb3 +-MoO42 − dimers to Er3 +.