RUI: Investigation of Electron Migration and Trapping in Doped Luminescent Materials

技术说明：本研究计划主要探讨真空紫外光激发下固态发光材料中电子-电洞对的输运与捕捉过程。这些材料由氧化物主体和稀土掺杂剂组成。在真空紫外激发下，在基质中产生电子-氢对，该电子-氢对必须迁移并被掺杂剂捕获以发生发光。本研究计划解决两个基本问题：（1）掺杂态相对于主体能带态的位置如何影响电子-氢转移的效率？(2)掺杂剂的选择对尺寸为50至500纳米的颗粒中观察到的表面损失程度有多大影响？这是通过对受控粒度的材料进行系统的光谱研究，并在当前模型的背景下对这些数据进行评估来实现的。这些实验数据的分析和建模允许在一个给定的主机中的电子-氢对的迁移率的评估，以及在何种程度上吸收的能量损失到体缺陷与表面陷阱。这种差异对于开发具有固有高表面积的高效纳米级光学材料尤其重要。该项目还将这些方法应用于更大的带隙磷酸盐hosts.Non-technical描述：本研究的目的是了解的基本结构/性能的关系，管理的效率固态发光材料，特别是亚微米颗粒尺寸的材料，在真空紫外激发。这种材料通常表现出与其本体对应物不同的特性，并且可以改善某些技术的性能，例如在高清晰度显示器中。PI在中央华盛顿大学建立了一个严格的固态化学研究计划，本科生组成了调查小组的大部分。学生正在获得更深入，更广泛的科学培训，这是为研究生院或未来的专业努力做好准备。在PI实验室接受培训的本科生经常在同行评审的期刊上发表论文，并定期继续攻读研究生学位。

Technical Description: This research project involves the study of electron-hole (e-h) pair transport and trapping processes in solid-state luminescent materials under vacuum ultraviolet excitation. These materials are comprised of an oxide host and a rare-earth dopant. Under vacuum ultraviolet excitation, an e-h pair is created in the host that must migrate and be trapped by the dopant for luminescence to occur. The research project addresses two fundamental questions: (1) How is the efficiency of e-h transfer affected by the position of dopant states relative to host band states? (2) How much does the choice of dopant influence the degree of surface loss observed in particles with sizes of from 50 to 500 nanometers? This is accomplished through systematic spectroscopic investigations of materials of controlled particle size, and the evaluation of these data in the context of current models. The analysis and modeling of these experimental data allow for the assessment of the mobility of e-h pairs in a given host, as well as the degree to which absorbed energy is lost to bulk defects versus surface traps. Such a differentiation is especially important to the development of efficient nanoscale optical materials that have an intrinsically high surface area. The project also applies these methods to larger bandgap phosphate hosts.Non-technical Description: The objective of this research is to understand the fundamental structure/property relationships that govern the efficiency of solid-state luminescent materials, especially materials with sub-micrometer particle sizes, under vacuum ultraviolet excitation. Such materials often exhibit properties different from their bulk counterparts, and can improve the performance of certain technologies such as in high-definition displays. The PI has established a rigorous research program in solid-state chemistry at Central Washington University, with undergraduate students comprising the bulk of the investigative team. Students are gaining a deeper and broader scientific training, which serves as excellent preparation for graduate school or future professional endeavors. Undergraduate students trained in the PI's lab often published papers in peer-reviewed journals and routinely go on to pursue graduate degrees.