Influence of Li+ codoping on visible emission of Y2O3:Tb3+, Yb3+ phosphor

Upon 980 nm diode laser excitation visible upconversion emission from the Tb3+ ions has been observed in combustion synthesized Tb3+-Yb3+ codoped Y2O3 phosphor. The intensity of upconversion as well as downconversion emission bands has been increased by codoping of Li+ ions into Tb3+-Yb3+:Y2O3 phosphor and the reason behind this increment is discussed. The pump power dependence of upconversion emission bands has shown two-photon absorption process. The cooperative energy transfer from Yb3+ to Tb3+ ions is supposed to be responsible for the upconversion emission from the Tb3+ ions on near infrared excitation. The calculated colour coordinates indicate the purity of intense green emission from present phosphor which is suitable for various photonic applications. (C) 2013 Elsevier B.V. All rights reserved.