Quantum Cutting in Ultraviolet B-Excited KY(CO):Tb Phosphors.

Highly efficient quantum cutting KY(CO):Tb phosphors excited by ultraviolet B (UVB) and ultraviolet C (UVC) were investigated. The structural and spectroscopic properties were characterized by XRD analysis and fluorescence spectrophotometry, respectively. The results showed that the monoclinic crystal structure of KY(CO):Tb remained in the Tb doping range of 0~100%. In the excitation spectrum, two intense excitation peaks were observed in the ultraviolet range. Under the excitation of 283 nm, the maximum quantum efficiency of KY(CO):0.7Tb could reach 119%. However, the most efficient quantum cutting occurred at the K excited state in the cross-relaxation of K + FD + D. The Tb content could be selected arbitrarily in the KY(CO) host without any concentration quenching. Optimal quantum cutting concentrations of Tb in KY(CO) were 0.7 and 0.3 for the excitation of UVB and UVC, respectively. UVB-excited phosphors are more popular with high transparency in products such as glass or resin. A quick response code was fabricated by resin to show the hidden information clearly. Therefore, the highly efficient phosphor could be a candidate material for the application in information identification technology.