Photoluminescence of Zinc Silicate Doped with Al and Ti

Abstract

Photoluminescence of sintered zinc orthosilicate doped with Al or Ti has been measured in the temperature range between 20 and 650 K, peak emissions being noted at 407 and 400 nm, respectively. The corresponding excitation spectra show peaks at 218 and 236 nm for Zn2SiO4:normalAl and at 218 and 232 nm for Zn2SiO4:normalTi . The 218 nm peak must be assigned to the excitation of the undoped zinc silicate where doping with Al as well as Ti effects an enhancement of this band. The two phosphors have different decay times at room temperature ( Zn2SiO4:normalAl,t≈10sec ; Zn2SiO4:normalTi,t≈10−3sec ). We observed the greatest quantum efficiency for the u.v.‐blue emission approximately at activator concentrations of 1 mol percent (m/o) Al or 0.6 m/o Ti. Deviations from the linear dependence of the luminescence intensity on the photoexcitation intensity are observed above 400 K.

Effects of dopant concentration and annealing temperature on the phosphorescence from Zn2SiO4: Mn2+ nanocrystals

“…For 850 1C annealed sample, the t f ¼ 0:49 ms and t s ¼ 10:73 ms are obtained, whereas for 1000 1C annealed sample, the fast and slow components are 1.01 and 19.52 ms (Table 2), respectively. The only willemite lattice of zinc silicate is formed at higher temperatures (850 and 1000 1C) which is a rhombohedra structure [13] consisting of cornerjoined tetrahedral group of [ZnO 4 ] and [SiO 4 ]. This structure houses two in equivalent Zn sites both having four nearest-neighbor oxygens in a slightly distorted tetrahedral configuration.…”

“…Used in early luminescent lighting, manganese-doped zinc silicates are well known as green phosphors [1]. Important for color rendering, a host lattice of Zn 2 SiO 4 containing Eu 3+ , Mn 2+ or Ce 3+ dopant ions covers the red, green, and blue portions of the visible spectrum, respectively [11][12][13][14][15][16][17]. Nanophosphors based on the rare-earth and transition metals are receiving considerable attention as potential coatings in lamps, cathode ray tubes [1], flat panel displays, electroluminescent and optoelectronic devices [11] and more recently, radiation detectors in medical imaging systems [18].…”

Developments in Luminescence and Display Materials Over the Last 100 Years as Reflected in Electrochemical Society Publications [Journal of the Electrochemical Society, 149, S69 (2002)]

“…Ozawa 148 reported on the motion of electrons and holes in Y 2 O 2 S crystal as revealed by cathodoluminescence. Kitahara et al 149 discussed the one-dimensional photoluminescence distribu- Hess et al 150 studied in 1983 the photoluminescence of sintered Zn 2 SiO 4 doped with Al and Ti. The quantum efficiency for the UVblue emission was measured as well as the decay time, which varied from 10 Ϫ3 s for Ti to 10 s for Al doping.…”

Developments in Luminescence and Display Materials Over the Last 100 Years as Reflected in Electrochemical Society Publications

“…Hess et al 150 studied in 1983 the photoluminescence of sintered Zn 2 SiO 4 doped with Al and Ti. The quantum efficiency for the UVblue emission was measured as well as the decay time, which varied from 10 Ϫ3 s for Ti to 10 s for Al doping.…”