This Small Business Innovation Research Phase I project proposes developing a novel molten salt heat transfer and thermal storage material for central receiver solar thermal power generation. Solar thermal technology developers are pushing to increase the operating temperature of their systems, thereby lowering their levelized cost of electricity and reducing the cost of energy storage. Known salt mixtures considered for heat transfer fluids have high melting points (typically over 300 °C) or insufficient thermal stability. In this effort, we will conduct a high throughput materials discovery program to rapidly screen over 2000 unique mixtures of inorganic salts and to discover a novel eutectic mixture with a low melting point of 200 °C and a high maximum temperature of 700 °C. This broad operating range is currently unavailable with any commercially viable material in the marketplace. Discovering new eutectic mixtures is a combinatorial problem, since the number of possible mixtures increases exponentially with the number of components. We will apply combinatorial chemistry techniques, originally developed for pharmaceutical applications, to a new field: solar thermal materials. In this project, we will combine the power of high throughput discovery tools (for fast materials synthesis and characterization) with an optimized methodology for experiment design (to efficiently constrain the design space). <br/><br/>The broader impact/commercial potential of this project addresses pressing concerns about energy. The goal is cheap solar power, day and night. It is imperative that we reduce our usage of fossil fuels (especially coal) to address societal concerns: climate change and environmental degradation, energy security, and price volatility. Solar thermal power, a compelling source of renewable electricity, represents a possible solution to excessive fossil fuel use. However, electricity from solar thermal power currently costs too much to be directly competitive with fossil fuels. Furthermore, although solar thermal plants have the capability of storing heat in order to produce power after sundown, this represents a significant capital cost to plant developers. In order to achieve large scale deployment and to compete with fossil fuels, there is a crucial need across the solar thermal industry to lower costs and develop viable thermal storage. At the heart of these plants is the heat transfer fluid and thermal storage material. The market for this crucial component is projected to reach $5.5 billion by 2020. The commercialization of the proposed innovation would both reduce the cost of solar thermal power and enable economic thermal storage, bringing the nation significantly closer to eliminating the use of coal.