The System Ag-S-Se: Phase Relations, Electrical and Opticalperties, and Applications

Ag-S-Se系统在材料研究中引起了相当大的兴趣，因为这些元素在固体中具有典型的光学、电学和热电性质。通常认为有三种化合物在室温下表征该体系：Ag2S(单斜晶系)、Ag4Se(正交系)和Ag2Se(正交系)。最近我们合成了一系列的中间体化合物，从纯的硫化银，到硫化银，再到纯的硒化银。组成系列似乎分裂成两个固溶体，一个从Ag2S延伸到大约Ag4SO.65Se1.35，另一个围绕Ag4SO.65Se1.35到Ag2Se。在这个项目中，我们希望：1.)绘制了Ag-S-Se系的相图，确认了两种固溶体的结晶学性质。2.)记录这些化合物的电学、光学和热电性质。3.)研究了这些材料作为薄膜的制备。4.)确定这些材料可能的商业应用(例如，干电池、热传感器、电致变色显示器、非线性光电子器件)。这个项目代表了对可能具有有趣的电学、光学和热电性质的新材料的行为的第一次审视。由于这些材料形成固溶体，它们的行为应该随着成分的变化而不断变化，有可能在化学计量的基础上创造出“设计者属性”。

The system Ag-S-Se is of considerable interest in materials research due to the optical, electrical, and thermo-electrical properties which typify these elements in the solid state. Three compounds are generally recognized as characterizing the system at room temperatures: Ag2S (monoclinic), Ag4SSe (orthorhombic), and Ag2Se (orghorhombic). Recently we have synthesized a series of intermediate compounds ranging in composition from the pure silver sulfide, through the silver sulfo- selenide, to the pure silver selenide. The compositional series appears to break into two solid solutions, one extending from Ag2S to approximately Ag4SO.65Se1.35 and the other encompassing Ag4SO.65Se1.35 to Ag2Se. In this project we hope to: 1.) Produce the phase diagram for the system Ag-S-Se and confirm the crystallography of the two solid solutions. 2.) Document the electrical, optical, and thermoelectric properties of these compounds. 3.) Investigate the fabrication of these materials as thin films. 4.) Determine possible commercial applications (e.g., dry cells, thermal sensors, electrochromic displays, non-linear optoelectronic devices) of these materials. This project represents the first look at the behaviors of new materials that are likely to possess interesting electrical, optical, and thermoelectric properties. Because the materials form solid solutions, their behaviors should be continuously variable with composition, with the potential for the creation of "designer properties" based on stoichiometry.