Visible emission of rare-earth-doped ZrO2 nanocrystalline phosphor under UV and IR excitation

The photoluminescence and crystalline structure characterization of undoped and several samarium and erbium doped ZrO 2 samples are reported. Strong visible fluorescence emission produced by the transitions 4 G 5/2 → 6 H 5/2,7/2,9/2 of Sm 3+ was obtained by the excitation of the host at 320 nm (downconversion). Green (545 nm) and red (680 nm) emissions bands were observed under 962 nm excitation (upconversion). Experimental results showed that the emission bands could be tuned by controlling the Er 3+ concentration. In particular, for the highest Er 3+ concentration, the red band is enhanced under 962 nm excitation. The nature of this behavior is discussed taking into account the concentration dependent non-radiative energy transfer ( 4 I 13/2 + 4 I 11/2 ) → ( 4 F 9/2 + 4 I 15/2 ) and cross-relaxation ( 2 H 11/2 + 4 I 15/2 ) → ( 4 I 9/2 + 4 I 13/2 ) process.