Despite many decades of developments in the field of materials chemistry, there are still only a limited number of ways to synthesize functional materials –– the majority of which require highly energy- and capital-intensive conditions. As such, there is a need to develop new rational methodologies for the synthesis of functional materials under more benign conditions, much in the same way that organic chemists have developed a very extensive and diverse toolbox of bench-top reaction chemistry. The Brutchey Group is developing new synthetic routes to compositionally complex inorganic nanocrystals and thin films using low-temperature, high yielding, and scalable methods, and is subsequently studying the growth mechanisms, structure, and functional properties of these materials. Ultimately, our hope is that this will lead to a "materials by design" approach, whereby tailored materials can be rationally synthesized for particular applications.
Semiconductor Inks for Low Cost Thin Film Deposition
One way to lower the cost of semiconductor processing is to develop “inks” for the solution-phase deposition of semiconductor thin films. One possible way to do this is a dissolve and recover approach, whereby a bulk semiconductor is dissolved, solution deposited, and then recovered as a crystalline thin film via heating. However, most bulk metal chalcogenide semiconductors are completely insoluble in common solvents. We have discovered a solvent mixture of amines/thiols that dissolves bulk metal chalcogenides, elemental sources, and metal oxides in high concentrations at room temperature and ambient pressure. The resulting semiconductor inks can be inexpensively solution deposited (e.g., via spray coating) and heated to recover highly crystalline and phase-pure metal chalcogenide films. This chemistry is being applied to the fabrication of metal chalcogenide films that are comprised of Earth abundant elements that hold promise for solar cells, thermoelectrics, transistors, and electrocatalysts.
Multinary Nanocrystals for Energy Storage and Conversion
The Brutchey Group has developed rational methods to synthesize high-quality multinary nanocrystals, such as perovskites. We use synchrotron techniques to study the average and local structure of these nanocrystals as a function of their size and composition in order to develop structure-property relationships. Particular attention is being paid to modifying the surface chemistry of these nanocrystals and studying the effect of surface modification on their structure and functional properties. By controlling the composition and surface chemistry of the nanocrystals, we possess a fine level of control over the properties of the final material. Ultimately, these nanocrystals are being used for energy conversion, energy storage, and catalysis applications.