Quantum Cutting in KGd(CO(3))(2):Tb(3+) Green Phosphor

Phosphors with a longer excitation wavelength exhibit higher energy conversion efficiency. Herein, quantum cutting KGd(CO(3))(2):Tb(3+) phosphors excited by middle-wave ultraviolet were synthesized via a hydrothermal method. All the KGd(CO(3))(2):xTb(3+) phosphors remain in monoclinic structures in a large Tb(3+) doping range. In the KGd(CO(3))(2) host, (6)D(3/2) and (6)I(17/2) of Gd(3+) were employed for quantum cutting in sensitizing levels. The excited state electrons could easily transfer from Gd(3+) to Tb(3+) with high efficiency. There are three efficient excited bands for quantum cutting. The excited wavelengths of 244, 273, and 283 nm correspond to the transition processes of (8)S(7/2)→(6)D(3/2) (Gd(3+)), (8)S(7/2)→(6)I(17/2) (Gd(3+)), and (7)F(6)→(5)F(4) (Tb(3+)), and the maximum quantum yields of KGd(CO(3))(2):Tb(3+) can reach 163.5, 119, and 143%, respectively. The continuous and efficient excitation band of 273–283 nm can well match the commercial 275 nm LED chip to expand the usage of solid-state light sources. Meanwhile, the phosphor also shows good excitation efficiency at 365 nm in a high Tb(3+) doping concentration. Therefore, KGd(CO(3))(2):Tb(3+) is an efficient green-emitting phosphor for ultraviolet-excited solid-state light sources.