基于β-Ca3(PO4)2骨架构筑的新型可控光致变色材料及机理研究

The light effect shows advantages of remote control, high efficiency and speed, which makes photochromic materials find great application prospects in high-tech fields, such as optical information storage, ink-free optical printing, rewritable media, sensors and smart windows. Traditional inorganic photochromic materials present many problems, including low contrast, slow photo response, limited color change variety and poor fatigue resistance. In this proposal, a series of novel inorganic photochromic materials with high efficiency and controllability will be constructed on the basis of β-Ca3(PO4)2 framework. The effective control of photochromic contrast can be realized by the change of traps distribution via introducing co-doped ions. The bimodal absorptions and color changes can be achieved by Eu2+, Mn2+ double doping and the adjustment of the ratio between them, respectively. The modulation of energy band structure and crystal field through the reasonable substitution of the corresponding cations can realize the effectively control on photo-response sensitivity and color diversity. With the aid of a series of characterization techniques, we intend to systematically investigate the effects of crystal structure, micromorphology, traps distribution and crystal field changes on the photochromism performance. The photochromic materials with excellent performance and practical value will be developed by optimization. Moreover, we will combine the experimental results with the first principle calculations, to reveal the nature of photochromism phenomenon, construct a dynamic model, and lay a foundation for the design and study of new photochromic materials in future.

光作用具有远程控制、高效、快捷的优点，使得光致变色材料在信息光存储、无墨光印刷、可重复式书写、传感器和智能窗户等高新领域具有重大应用前景。传统的无机光致变色材料存在着诸多问题，如对比度低、光响应速度慢、颜色变化单一以及抗疲劳性差。本项目拟以β-Ca3(PO4)2骨架为基础，构筑一系列高效且变色性能可控的新型无机光致变色材料。通过引入共掺杂离子改变陷阱的分布，实现变色对比度的有效调控。通过Eu2+-Mn2+双掺杂及二者比例的调节分别实现双峰吸收和颜色的调控。通过对相应阳离子的合理置换改变能带结构和晶体场环境，达到光响应灵敏度和变色材料颜色多样性的有效调控。借助一系列表征技术系统研究结构、微观形貌、陷阱分布以及晶体场变化对变色性能的影响。开发出性能优异具有实用价值的光致变色材料。同时，结合第一性原理，揭示光致变色本质，构建动力学模型，为未来新型光致变色材料的设计和研究奠定基础。

光致变色材料具有高效、远程全光控制、实时响应等优点，在信息光存储、无墨光印刷、可重复式书写、光调制等方面具有巨大的应用前景。传统的无机光致变色材料面临着对比度低、光响应速度慢、颜色变化单一及抗疲劳性差等诸多缺点。本项目的实施通过工艺流程的优化，成功合成了一系列Eu2+掺杂的新型磷酸盐无机光致变色材料。通过离子双掺杂，改变陷阱的分布，从而实现了对变色对比度的调控；通过阳离子置换(如碱土金属离子连续替换)成功合成了连续固溶体，实现了光致变色材料颜色变化多样性的连续调控。同时，碱土金属阳离子的替换以及其它离子共掺杂有效地造成了晶体场，能带结构以及态密度的改变，从而有目的地实现了发射峰位的调控以及光调控过程光响应灵敏度的改善。研究了掺杂浓度、紫外光辐照的强度和时间与变色程度的关系。通过漫反射谱，荧光光谱对该种材料的光致变色性能进行了系统性表征并验证了其光致变色良好的抗疲劳性。通过EPR、热释光等技术手段对光致变色电子动力学过程进行了详细表征和深入分析，揭示了氧空位作为陷阱在光致变色过程中对电子的俘获和释放所起到的关键作用。实验表征与第一性原理理论计算相结合，深入讨论了光致变色机理，并提出了相应的光致变色动力学机理模型，为以后进一步研究提供一定的理论指导。将光致变色材料与PDMS融合，封装成柔性光致变色介质，初步实现了有效的远程荧光调制、寿命调制、光学防伪、可擦除式光信息存储、无墨光印刷以及瞬时高温记录等6种场景应用。.在本项目的支持下共发表相关SCI论文18篇；国家发明专利申请5项，授权3项；独立与共同培养研究生10名(其中已毕业4名，在读6名)。