Structure and Upconversion Luminescence Properties of Pr3+-Doped Y2SiO5 Phosphor

Abstract

Ultraviolet-C light has significant application prospects in the fields of disinfection, air purification, etc. Herein, an effective UVC upconversion phosphor Y 2 SiO 5 :Pr 3+ was successfully prepared, as evidenced by the XRD results. The diffuse reflection spectra of Y 2 SiO 5 : Pr 3+ phosphors presented two distinct absorption bands corresponding to the electron transitions of 3 H 4 → 3 P 2 and 3 H 4 → 1 D 2 , and the E g was determined to be 4.22 eV for the Y 2 SiO 5 host, which is very close to the E g (4.172 eV) calculated by DFT. Under the excitation of 460 nm laser, two emission peaks centered at ~247 nm and ~ 258 nm were found in the range of 230-280 nm, which are attributed to the transitions of 4 f 5 d → 3 H 4 and 4 f 5 d → 3 H 5 of Pr 3+ ions. With the help of temperature-dependent emission spectra, the phosphor demonstrated impressive thermal stability up to 150 °C. These findings indicate that the Y 2 SiO 5 : Pr 3+ phosphor has the potential application in disinfection.

Theoretical Determination of the Electronic Structures and Energy-Level Splitting for Pr3+-Doped Y2SiO5 Crystals

“…Y 2 SiO 5 :Pr (I) possesses a band gap of 3.985 eV, and Y 2 SiO 5 :Pr (II) has a band gap of 4.145 eV. These results are slightly smaller than the calculated band gap of pure Y 2 SiO 5 (4.172 eV) but larger than the Yb 3+ -doped Y 2 SiO 5 crystals studied by Zhou et al Therefore, the doping of Pr 3+ induces a reduction in band gaps for the host Y 2 SiO 5 crystal. It is obvious that the energy bands of Y 2 SiO 5 :Pr (I) and Y 2 SiO 5 :Pr (II) are divided into three parts, which contain the conduction bands with energy larger than 6.75 eV, the valence bands with energy smaller than the Fermi level, and the bands at around 4 eV.…”

“…20 Due to the crystal field interactions of Pr 3+ in the host Y 2 SiO 5 , the 3 H 4 and 1 D 2 states can further split to 9 and 5 Stark levels, respectively. And it could be possible to detect single ions via the 3 nm are due to the transitions of 4f5d → 3 H 4 and 4f5d → 3 H 5 of Pr 3+ ions. 3 For the detailed transition spectrum, Cheng-Lin et al reported the optical properties of the Y 2 SiO 5 :Pr crystal, including absorption spectrum, excitation spectrum, and fluorescence attenuation.…”

“…And it could be possible to detect single ions via the 3 nm are due to the transitions of 4f5d → 3 H 4 and 4f5d → 3 H 5 of Pr 3+ ions. 3 For the detailed transition spectrum, Cheng-Lin et al reported the optical properties of the Y 2 SiO 5 :Pr crystal, including absorption spectrum, excitation spectrum, and fluorescence attenuation. 4 The fluorescence quantum efficiency was derived by theoretical calculations within the 4f 2 configuration and from 4f5d to 4f 2 transition probabilities using the Judd−Ofelt (J−O) theory.…”

“…The low thermal conductivity, low oxygen conductivity, and relatively high coefficient of thermal expansion of Y 2 SiO 5 ensure that it can be a very competitive candidate material for thermal and oxygen-resistant coatings. More importantly, the host Y 2 SiO 5 is a monoclinic crystal with a C 2 space group . Y atoms can be coordinated with seven oxygen atoms or six oxygen atoms, thus forming the local [YO 7 ] −11 or [YO 6 ] −9 complex ligands, respectively.…”

Synthesis and Upconversion Luminescence of LiY9(SiO4)6O2 Phosphor Doped with Pr3+

“…Pr 3+ -doped Y 2 SiO 5 and Li 2 SrSiO 4 show efficient UVC upconversion between 250 and 340 nm when excited by a 450 or 460 nm laser. 10,11 Moreover, Li 2 SrSiO 4 :Pr 3+ can effectively inactivate bacteria within 10 min, 11 which proves that silicate phosphors are promising matrices for UVC-based antibacterial applications.…”