The rare earth Ce3+ ion doped SiO2-B2O3-BaO-Gd2O3 system is synthesized by high-temperature melting method. The density, transmission, excitation spectra and scintillating properties of the glasses are investigated. The results indicate that all the samples have good physical and scintillating properties. The emission peak wavelength of all samples is 390 nm under X-ray radiation. Gd3+ ions have a negative impact on scintillating properties when its concentration reaches a certain level. Gd3+ ions sensitize the luminescence of Ce3+ ions, and the ideal concentration is 15 mol% for Gd3+ ions. Also the decay characteristics of Ce3+ and Gd3+ ions are investigated. These samples have potential practical applications in high energy physics.
The Tb^(3+)/Sm^(3+) single-doped and co-doped glasses and glass ceramics containing YPO_4 nanocrystals have been synthesized by melt quenching method. The structural and luminescent properties of these glass specimens were investigated. Under 375 nm wavelength excitation, the emission spectra combined with blue, green and red bands were observed, which achieved the white light emission. Moreover, the energy transfer between Tb^(3+) and Sm^(3+)ions was validated by decay lifetime measurement and energy level diagram.The color coordinates(x = 0.333, y = 0.333), correlated color temperature(5595 K) and the color rendering index(Ra = 80.5) indicated that the glass ceramics were considered to be good lighting source. Hence,the YPO_(4-) based Tb^(3+)/Sm^(3+) co-doped glass ceramics can act as potential matrix materials for white lightemitting diodes under ultraviolet excitation.
Pr3+and Yb3+co-doped phosphate glasses are prepared to study their optical properties.Excitation and emission spectra and decay curves are used to characterize their luminescence.We demonstrate that upon excitation of Pr3+ion with one high energy photon at 470 nm,two near-infrared(NIR)photons are emitted at 950-1100 nm(Yb3+:2F 5/2 →2F 7/2)through an efficient cooperative energy transfer(CET)from Pr3+to Yb3+.The maximum energy transfer efficiency(ETE)and the corresponding quantum efficiency approach up to 90.17%and 190.17%,respectively.The glass materials might find potential application for improving the efficiency of silicon-based solar cells.
Glass ceramics Ba2 La F7:x Dy3tare obtained through the conventional melt-quenching technique, and their luminescent properties are investigated. Under 350 nm excitation, the emission spectra consists of a strong blueyellow band as well as a weak red emission centered at 660 nm, which are attributed to the4F9∕2→6H15∕2,4F9∕2→6H13∕2and4F9∕2→6H11∕2transitions of the Dy3tion, respectively. The corresponding Commission Internationale de L'Eclairage(CIE) chromaticity coordinate for a sample of 2 mol.% Dy2O3 after being heat-treated at 690°C is(0.313, 0.328). It is concluded that the formed materials may have the possibility of applications for white light-emitting diodes(LEDs).
The phosphate glasses doped with Eu2+,Gd3+,respectively,and co-doped with Gd3+and Eu2+were prepared by high-temperature melting method.The transmission spectra,the excitation spectra,the emission spectra and the fluorescent decay time were investigated.The energy transfer process between Gd3+and Eu2+was studied.From the excitation spectra and the emission spectra of the phosphate glasses doped with Eu2+,we observed that the emission intensity of Eu2+shows higher for 0.02 mol% Eu2+-doped phosphate glass.According to the excitation spectra and the emission spectra and the fluorescence decay curves,when the concentration of Eu2+was 0.02 mol%,the optimal concentration of Gd3+was 0.3 mol%.Based on Dexter theory,it is shown that the energy transfer between Gd3+and Eu2+was nonradiation energy transfer by analyzing the energy-level diagram.The fluorescence decay curves of Gd3+were expressed by the Inokuti–Hirayama's model and were used to analyze energy transfer mechanism between Gd3+and Eu2+.And the energy transfer efficiency was also calculated.
