Upconversion luminescence properties and color tunability of 12CaO⋅7Al2O3:Ho3+/Yb3+ single crystal

Abstract

Rear earth (RE) ions-doped 12CaO[Formula: see text]7Al2O3 single crystal has been successfully prepared by Czochralski method. Under 980 nm excitation, a strong green upconversion emission at 548 nm and a weaker red upconversion emission at 662 nm were observed. The green upconversion emission is corresponding to the transition of 5F 4/5S[Formula: see text]I8 of Ho[Formula: see text], and the red one is corresponding to the transition of 5F[Formula: see text]I8 of Ho[Formula: see text]. A much weaker NIR band at 762 nm is also observed, which corresponds to the 5F 4/5S[Formula: see text]I7 transition of Ho[Formula: see text]. The pump dependence and luminescence decay dynamics spectra show the green and red upconversion are populated by two-photon process, and the upconversion mechanisms are analyzed in detail. The color of the upconversion luminescence can be changed by simply adjusting the excitation power. RE ions-doped 12CaO[Formula: see text]7Al2O3 single crystal with these properties is expected to have broad application prospects in solid-state multicolor display and instrument integration. RE ions-doped 12CaO[Formula: see text]7Al2O3 single crystal has the ability to replace some traditional single crystals such as LiNbO3 in many applications.