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

Abstract

Rear earth (RE) ions-doped 12CaO · 7Al 2 O 3 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 5 F 4 / 5 S 2 → 5 I 8 of Ho 3+ , and the red one is corresponding to the transition of 5 F 5 → 5 I 8 of Ho 3+ . A much weaker NIR band at 762 nm is also observed, which corresponds to the 5 F 4 / 5 S 2 → 5 I 7 transition of Ho 3+ . 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 · 7Al 2 O 3 single crystal with these properties is expected to have broad application prospects in solidstate multicolor display and instrument integration. RE ions-doped 12CaO · 7Al 2 O 3 single crystal has the ability to replace some traditional single crystals such as LiNbO 3 in many applications.