[Luminescence Characteristics of Scintillator Y2SiO5∶Ce]

Guang Pu Xue Yu Guang Pu Fen Xi. 2016 Aug;36(8):2399-2404.
[Article in Chinese]

Abstract

Cerium doped Y2SiO5 (YSO) is an important scintillator material due to its high density, non-hygroscopic, excellent light output and fast decay time nature. in the paper, Y2SiO5∶Ce3+0.2%(YSO∶Ce) was grown with high-temperature solid-phase method. The time-resolved excitation and emission spectra and fluorescent decay curves at low temperature and room temperature (RT) were measured and discussed. There were two types of luminescence, one was the crystal defect emission, the center at 320 nm; the other one was doped Ce3+ ions 5d→4f emission, the center at 440 nm. Only when the excitation energy (Ex) was greater than the band gap width (Eg), the crystal defect emission can be observed corresponding to slow process, and the emission intensity was higher at low temperature. The crystals defect emission was hardly observed in the time-resolved emission spectra when the temperature rose to room temperature because of temperature quenching. Regions from 60~300 nm corresponding to emission due to 5d→4f transitions in the activator Ce3+ ions peaks at 440 nm, a plurality of excitation peaks were observed. Among them, the excitation with energy less than 6.1 eV(Ex<Eg) was the direct excitation band belonging to the 5d energy level of Ce3+ ions. The corresponding excitation emission was fast process. Two emission peaks centering at 392 and 426 nm were observed at low temperature, corresponding to the Ce3+ ion electron transition from the lowest 5d level to the two spin-orbit 4f ground state of Ce3+(2F5/2, 2F7/2). With increasing temperature the doublet was thermalized and at RT the emission peak separation cannot be observed. At 200 and 300 K, when the excitation energy (Ex) was greater than the band gap width (Eg), decay curve had obvious rising edge, which shows that some energy is transmitted to Ce3+ ions.