A combinatorial approach to the discovery of advanced materials

This thesis discusses the application of combinatorial methods to the search of advanced materials. The goal of this research is to develop a "parallel" or "fast sequential" methodology for both the synthesis and characterization of materials with novel electronic, magnetic and optical properties. Our hope is to dramatically accelerate the rate at which materials are generated and studied.; We have developed two major combinatorial methodologies to this end. One involves generating thin film materials libraries using a combination of various thin film deposition and masking strategies with multi-layer thin film precursors. The second approach is to generate powder materials libraries with solution precursors delivered with a multi-nozzle inkjet system. The first step in this multistep combinatorial process involves the design and synthesis of high density libraries of diverse materials aimed at exploring a large segment of the compositional space of interest based on our understanding of the physical and structural properties of a particular class of materials. Rapid, sensitive measurements of one or more relevant physical properties of each library member result in the identification of a family of "lead" compositions with a desired property. These compositions are then optimized by continuously varying the stoichiometries of a more focused set of precursors. Materials with the optimal composition are then synthesized in quantities sufficient for detailed characterization of their structural and physical properties. Finally, the information obtained from this process should enhance our predictive ability in subsequent experiments.; Combinatorial methods have been successfully used in the synthesis and discovery of materials with novel properties. For example, a class of cobaltite based giant magnetoresistance (GMR) ceramics was discovered; Application of this method to luminescence materials has resulted in the discovery of a few highly efficient tricolor luminescence materials, some of them also have superior color coordinates for potential applications in displays and imaging technologies. Various masking forms (physical and lithographic) and methods (binary, quaternary, X-Y shutter mask) were also applied to increase the efficiency of thin film combinatorial synthesis.; This thesis is basically a compilation of my publications in combinatorial methods. The first chapter will review the current development of combinatorial methods to the search of advanced materials. The second chapter will overview the development of instrumentation related to the combinatorial method. The third chapter will discuss its application in search of superconductors and GMR ceramics. The fourth chapter will illustrate its applications in photoluminescent materials. The last chapter will discuss the application of inkjet technology to the fabrication of powder material libraries.