喷雾热解法制备的SrWO4膜的阴极射线发光

利用超声喷雾热解法制备了钨酸锶SrWO₄多晶发光膜,并研究了制备条件及掺杂对其阴极射线发光特性的影响.生成的发光膜在300℃以上退火后具有白钨矿结构,其阴极射线发光为一宽带的蓝光,包括一个位于448nm的蓝色发光带和一个位于488.6nm的蓝绿色发光带,是由阴离子络合物WO₄^2-的电荷转移跃迁引起的.发光强度随着退火温度的升高而增强,而退火气氛对其影响不大.在SrWO₄膜中掺入银离子Ag⁺和镧离子La³⁺后,不影响其发光特性,但铕离子Eu³⁺的掺入对发光特性有影响.

Cathodoluminescence of SrWO4 Films Prepared by Spray Pyrolysis

The second group metal tungstates have attracted particular attention because they have practical importance as laser host materials in quantum electronics and scintillators in medical applications. The luminescence of SrWO₄, which can be excited by short-wavelength ultraviolet radiation, X-rays, cathode rays etc., mainly shows a blue emission spectrum. It is generally agreed that a thin film phosphor has superior resolution compared to powders because of its smaller grain size and less lateral scattering. Less extensive investigation has been made on the preparation of the SrWO₄ films. A variety of physical and chemical deposition methods including sputtering deposition, electron beam evaporation and electrochemical method have been reported for the preparation of SrWO₄ films. In addition to these techniques, spray pyrolysis method is very interesting because of its advantages of no vacuum, simple instrumentation and low cost. In this paper, SrWO₄ films were prepared on glass substrates by spray pyrolysis. The effects of preparation conditions and monovalent, bivalent and trivalent cation doping on cathodoluminescence (CL) properties of the films were studied. Polycrystalline SrWO₄ films formed a scheelite structure after being annealed above 300℃. They exhibited cathodoluminescence consisting of a blue emission band at 448nm and a blue-green emission band at 488.6nm. The blue and blue-green emission intensities increased with annealing temperature. Annealing atmosphere and doping with Ag⁺ and La³⁺ did not influence the characteristics of the blue and blue-green emissions, whereas Eu³⁺ did. The results indicated both the blue and blue-green emissions originated from the charge transfer transition of WO₄^2- groups.