Broadband UV excitable near-infrared downconversion luminescence in Eu 2+/Yb 3+:CaF 2 nanocrystals embedded glass ceramics

Abstract

Cooperative downconversion was realized in glass ceramics containing Eu 2+/Yb 3+:CaF 2 nanocrystals with Eu 2+ greatly absorbing ultraviolet photons. Upon excitation of Eu 2+ ions to the 5 d level with an ultraviolet photon at 320 nm, emission of two near infrared photons at 976 nm of Yb 3+ were achieved. The dependence of the visible and near-infrared emissions, decay lifetime, and quantum efficiency on the Yb 3+ doping content has been investigated. The maximum energy transfer efficiency and the corresponding downconversion quantum efficiency were estimated to be 51% and 151%, respectively.