蓝紫色ZnO-Al_2O_3-SiO_2长余辉陶瓷

Blue Long-Lasting Phosphorescence Ceramic Based on ZnO-Al_2O_3-SiO_2

通过高温固相法首次合成并报道了兰紫色ZnO Al2O3 SiO2长余辉陶瓷,系统地研究了其发光和缺陷性质。在强度0.6mW·cm-2,主峰254nm的UVP紫外灯下激发15min,然后关闭激发源,样品发射兰紫色长余辉。撤去激发源以后5s,余辉初始强度为230mcd·m-2,色坐标为(0.1292,0.0984)。暗视场中,8h以后余辉仍然肉眼可辨。样品的紫外可见发射和不同时间的余辉发射光谱显示:荧光发射位于390nm,来源于基质的自致发光;而余辉有两个发射峰,主峰位于390nm,肩峰位于520nm。这表明样品中存在两种余辉发射中心。由余辉衰减曲线可以看出,这两种余辉发光都由一个快过程和一个慢过程组成。其中,慢过程决定了材料的长余辉时间。从时间依赖的余辉强度倒数曲线可以看出,余辉强度与时间成反比,这表明余辉发光的机理为电子空穴复合过程。热释光谱显示:样品分别在92和250℃附近出现两个宽的热释峰,说明材料中至少存在两种具有不同陷阱深度的电子或空穴缺陷中心。

The blue long lasting phosphorescence ceramic based on ZnOAl2O3SiO2 was synthesized and reported by solid state reaction, whose properties of luminescence and defects were systematically investigated. After irradiated by UVP lamp peaking at 254 nm with a power of 0.6 mW·cm-2 for 15 min, the ceramic emits a blue long lasting phosphorescence peaking at about 390 nm, whose initial intensity is 230 mcd·m-2 with a color coordinate (0.1292, 0.0984) at 5 s after the removal of the UVP lamp. And it can be seen in the dark even 8 h by the eyes in the light perception of 0.32 mcd·m-2. The ultra-visible photoluminescence spectra show that there is a broad emission predominating at 390 nm, which is due to the selfemission of the ceramic. From the spectra of the long lasting phosphorescence measured at different time, it can be seen that there are two peaks of long lasting phosphorescence. One is centered at 390 nm and the other at 520 nm, which indicates two recombination centers in the ceramic. The decay of long lasting phosphorescence is consisted of two processes, i.e., a fast one and slow one. And it obeys t-1, which indicates the electronhole recombination in the long lasting phosphorescence process. The thermoluminescence spectra show that there are at least two kinds of electron or holetrapping center with different trap depth in the ceramic.