Spectroscopic Studies of Layered Solids

片状过渡金属磷三盐化合物是一类重要的二维半导体材料。这些化合物引起了研究人员的兴趣，因为它们具有高度的二维物理性质和不同寻常的固态化学。层状晶格表现出固态的“插层”反应，分子插入晶格平面之间。插层过程经常导致主体晶格的化学和物理性质发生戏剧性和不可预测的变化。尽管插层反应已经被研究了二十多年，但这些材料的固相插层化学中许多有趣的机理和结构问题仍然没有得到解决。这项建议中描述的研究旨在更好地理解这些材料的插层机理。电荷平衡是阳离子物种插层的重要制约因素，可以通过消除晶格阳离子来实现。建议利用电子自旋共振(ESR)谱来研究层间和层内阳离子之间的络合平衡。在许多反应中，涉及一种机制，在该机制中，电子被转移到主晶格中的未知位置。他们建议利用光致发光和光学检测磁共振(ODMR)光谱来确定晶格还原位置。

The lamellar transition metal phosphorus trichalcogenides form an important family of two-dimensional semiconducting materials. These compounds are of interest to researchers because of their highly two-dimensional physical properties and their unusual solid-state chemistry. The layered lattices exhibit solid-state "intercalation" reactions in which molecules insert between lattice planes. The process of intercalation often results in dramatic and unpredictable modification of the chemical and physical properties of the host lattice. Although the intercalation reactions have been studied for more than two decades, many interesting questions of mechanism and structure in the solid-state intercalation chemistry of these materials remain unresolved. The research described in this proposal is directed toward an improved understanding of the mechanism of intercalation in these materials. Charge balance is an important constraint to the intercalation of cationic species and may be achieved by elimination of lattice cations. It is proposed to utilize electron spin resonance (ESR) spectroscopy to study the complex equilibrium between inter- lamellar and intra-lamellar cations. In many reactions a mechanism is involved in which an electron is transferred to an unidentified site in the host lattice. They propose to utilize photoluminescence and optically detected magnetic resonance (ODMR) spectroscopy to determine the lattice reduction site.