Reversible colorless-cyan photochromism in Eu2+-doped Sr3YNa(PO4)(3)F powders
Reversible colorless-cyan photochromism in Eu2+-doped Sr3YNa(PO4)(3)F powders
复制标题
Eu2+掺杂Sr3YNa(PO4)(3)F粉末中可逆的无色-青色光致变色现象
DOI：
10.1039/c5tc01797a
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发表时间：
2015
影响因子：
6.4
通讯作者：
Mu Zhongfei
中科院分区：
文献类型：
--
作者：
Jin Yahong;Hu Yihua;Fu Yinrong;Chen Li;Ju Guifang;Mu Zhongfei
光致变色材料作为光开关和可擦除光存储介质引起了人们越来越大的兴趣。在这里，我们报道了一种新型的可逆无色青色光致变色粉末材料Sr3YNa(PO4)3F：Eu2+。用不同波长的光照射粉末不同的照射时间或热处理后的反射光谱表征了粉末的光致变色性能，包括着色和漂白。结果表明，Eu2+可被短波长光(200~320 nm)着色、长波长光(320~800 nm)漂白或240℃热处理，Eu2+的最佳掺杂浓度约为0.5mol%。在光致变色性能上表现出较高的抗疲劳性。短波长辐射到Eu2+较高的5d态激发并被陷阱俘获的4f基态中的电子负责着色过程。相应地，捕获的电子从两种不同深度的陷阱中释放出来，导致了最初的快速和后来的缓慢的漂白过程。讨论了电荷载流子运动在两个不同陷阱之间的关键作用。根据所获得的结果，可以半定量地解释无色青色光致变色现象。提出了一个初步的模型来解释PC的机理。
Photochromic materials have attracted increasing interest as optical switches and erasable optical memory media. Here, we report on a novel reversible colorless-cyan photochromic powder material Sr3YNa(PO4)3F:Eu2+. The photochromic properties including coloring and bleaching are characterized by reflectance spectra after the powder is irradiated by different wavelengths of light for different irradiation times or processed by thermal treatment. The results show that it can be colored by short wavelength light (200–320 nm) and bleached by longer wavelength light (320–800 nm) or thermal treatment at 240 °C. The optimal doping concentration of Eu2+ is determined to be about 0.5 mol%. It shows high fatigue resistance in photochromism performance. Electrons in 4f ground levels excited by short wavelength irradiation to higher 5d states of Eu2+ and then captured by traps are responsible for the coloring process. Correspondingly, the release of trapped electrons from two kinds of traps with different depths causes the initially fast and later slow bleaching processes. The critical role of charge carrier motions between two different traps is discussed. The colorless-cyan photochromism can be explained semi-quantitatively on the basis of obtained results. A tentative model was proposed to illustrate the PC mechanism.