Molecular Synthesis and Characterization of Inorganic Chalcogenide Perovskites for Electronic Applications

Nontechnical description

The demand for innovative semiconductors is growing in response to technological progress across various sectors. There is a need for semiconducting materials with superior optoelectronic properties, which are composed of earth-abundant elements, are easy to synthesize, and are stable under operation. Such materials will have an impact on the design and fabrication of diverse semiconducting electronic devices, including solar cells, light-emitting diodes, thermoelectrics, detectors, and thin-film transistors.

Over the past two decades, an exciting class of new organic-inorganic lead halide perovskite semiconductors with exceptional optoelectronic properties have emerged. However, the poor air, moisture, light stability, and Pb toxicity of the lead halide perovskites have limited their wide-scale use. In response, a flurry of recent theoretical screening searches has identified alternative inorganic chalcogenide perovskites with similar crystal structures as lead halide perovskites and with a potential for equally promising optoelectronic properties.

These Chalcogenide perovskites are particularly attractive as they are composed of earth-abundant elements and would be amenable to use on a large scale without material supply limitations. However, to date, methods to synthesize these materials as thin films at temperatures typically employed in the device fabrication are not available. The project aims to make such synthesis and fabrication methods for chalcogenide perovskite nanoparticles and thin films available, to enable the study of their material and optoelectronic properties and contribute to their widespread use, especially in solar cells.

The project aims to fulfill the need for a chalcogenide perovskite database with experimental material and optoelectronic data along with experimentally validated models and tools to help in the tailoring and discovery of useful semiconducting materials for specific device applications by the material community. Furthermore, training graduate and undergraduate students in integrative research and education provides them with cross-disciplinary skills essential for developing innovative solutions as they contribute to U.S. leadership in the burgeoning field of semiconductors and electronic devices.

Technical description

To date, the synthesis of device-quality chalcogenide perovskite thin films at temperatures below 600 °C is unavailable. In this project, solution syntheses based on organometallic chemistry at manufacturable temperatures of below 600 °C and the ability to tailor thin film with the desired optoelectronic properties and device performance are being developed for the rich material space of chalcogenide perovskites ABS3 (A=Sr, Ba; B=Zr, Hf) especially BaZrS3.

The project seeks to provide a new understanding of early transition metal-chalcogen bonding and ligand chemistry in molecular precursors, solvents, and reaction sequences during subsequent processing steps for the synthesis of an entire class of chalcogenide perovskite materials and their nanoparticles and thin films. The ability to tune optoelectronic properties through composition control is also being developed.

Design insights for efficient light-harvesting solar cell assemblies promise to generate knowledge for efficient charge generation and transport over macroscopic distances across multiple interfaces within devices.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.