Preparation and up-conversion luminescence characteristics studies of K3YF6: Ho3+, Yb3+ with cryolite structure

Cryolite was considered to be an ideal up-conversion host material due to its low phonon energy, which can effectively suppress the radiation-free transition process of excited state energy levels. In the present paper, a novel up-conversion material K 3 YF 6 :Ho 3+ , Yb 3+ with cryolite structure was prepared successfully using a high-temperature solid state method. The up-conversion luminescence properties of K 3 YF 6 doped with different Ho 3+ /Yb 3+ doping ratio were investigated and the optimal doping ratio were confirmed in this system. Under 980 nm excitation, Ho 3+ /Yb 3+ co-doped K 3 YF 6 revealed a strong green emission at the 541 nm, 549 nm and a weak red emission peaking at 666 nm, corresponding to the 5 F 4 , 5 S 2 → 5 I 8 and 5 F 5 → 5 I 8 transitions of Ho 3+ , respectively. All the red and green up-conversion emission of K 3 YF 6 :Ho 3+ , Yb 3+ belong to two-photon process and energy transfer from Yb 3+ to Ho 3+ simultaneously. Additionally, to understand the energy transfer and electronic transition process of the red and green light emitted, the possible luminescence mechanism were also analyzed in this paper. All the results indicate that Ho 3+ /Yb 3+ co-doped K 3 YF 6 have potential application value in green up-conversion luminescent materials.