Structure and upconversion luminescence properties of Pr3+-doped Y2Si2O7 phosphor prepared by different methods

Ultraviolet-C (UVC) light shows important application prospects in disinfection, disease phototherapy, cancer photodynamic therapy, etc. Here, a novel UVC upconversion phosphor δ -Y 2 Si 2 O 7 :Pr 3+ with excellent optical properties was successfully prepared by the high-temperature solid-state reaction method and the sol-gel method. The XRD results clarified the law of phase transition from the β -/ γ -Y 2 Si 2 O 7 to the δ -Y 2 Si 2 O 7 phase. The diffuse reflection spectra of phosphors prepared by two different methods exhibited two obvious absorption bands related to the 3 H 4 → 3 P 2 and 3 H 4 → 1 D 2 transitions of Pr 3+ ions. And the values of the band gap were estimated by diffuse reflection spectra, which are in good agreement with the value calculated by DFT . Under the excitation of 460 nm laser, two emission peaks corresponding to the 4 f 5 d → 3 H 4 and 4 f 5 d → 3 H 5 transitions of Pr 3+ ions were discovered at ∼247 nm and ∼258 nm in the range of 230–280 nm. Additionally, the phosphor prepared by the sol-gel method has a higher emission intensity than the phosphor prepared by the high-temperature solid-state reaction method. With the help of temperature-dependent emission spectra , the phosphor prepared by two methods demonstrated outstanding thermal stability up to 150 °C, and the luminescent intensity at 150 °C remained 86.8% and 87.9% of that at ambient temperature, respectively. The results mentioned above suggest that the Y 2 Si 2 O 7 :Pr 3+ phosphor may have potential applications in the field of disinfection.