Strong Green and Red Upconversion Emission in Er3+-Doped Na1/2Bi1/2TiO3 Ceramics.

Upconversion emission properties of Na1/2Bi1/2TiO3:Er3+ ceramics prepared by the solid-state reaction method were analyzed as a function of Er3+ concentration and incident pump power. Strong green (550 nm) and red (670 nm) emission bands were observed with 980 nm excitation at room temperature. Experimental results showed that the emission bands can be tuned by changing Er3+ concentration. Upconversion processes in these samples result from not only a two-photon excited-state absorption process but also a nonradiative energy transfer and cross-relaxation process. [ABSTRACT FROM AUTHOR]