CAREER: Synthesis of Emerging Chalcogenide and Chalcohalide Semiconductor Nanomaterials

Mississippi State University, Mississippi State MS

Investigators

Abstract

Non-Technical Summary Many modern technologies rely on semiconductor materials for their function. For example, solar cells use semiconductors to absorb light and generate electricity. Scientists and engineers are continuously working to improve the efficiency and cost-effectiveness of solar cells to help decrease global dependence on non-renewable energy sources. Many promising new semiconductor materials have been proposed based on computations. Some of the materials that have been predicted to have excellent properties have been, so far, difficult to synthesize under the mild conditions that would make it possible to incorporate them into devices. This includes a class of materials known as chalcogenide perovskites, and certain other materials which contain mixtures of halide and chalcogenide ions. Through this award, jointly funded by the Solid State and Materials Chemistry program in the Division of Materials Research and the Established Program to Stimulate Competitive Research (EPSCoR) at NSF, Prof. Sidney Creutz is developing new methods to make some of these materials on the nanoscale under relatively mild conditions and is studying their electronic and optical properties to better understand their potential applicability in solar cells and other devices. Undergraduate and graduate students are trained in materials chemistry and gain exposure to alternative energy concepts, contributing to the development of a green energy workforce. This includes the development of a materials chemistry bootcamp to introduce new undergraduate students to research in this area. Additionally, outreach is carried out to high school students in the state of Mississippi to increase awareness about and interest in chemistry and its relationship to energy. Technical Summary There is a critical need for the development of new potential photovoltaic materials that may help spur the widespread global adoption of solar energy. With this CAREER project, Prof. Creutz will develop new synthetic approaches to emerging semiconductor nanomaterials, and to probe the properties of the resulting materials using a range of spectroscopic and chemical approaches. This work focuses on two general classes of materials: chalcogenide perovskites and chalcohalides, including split-anion perovskites. The first major objective is to study in detail the structure and optoelectronic properties (including luminescence and tunable absorbance) of nanocrystals of the chalcogenide perovskite barium zirconium sulfide and the related material barium titanium sulfide. The second major objective is to extend these synthetic methods to several classes of closely related materials that have been proposed to have promising optoelectronic properties, including alloys, layered phases, rare earth chalcogenide perovskites, and doped materials. The third major objective is to develop new synthetic approaches to mixed-anion chalcohalide materials, focused on a detailed fundamental understanding of heterovalent anion exchange between chalcogenides and halides. Integrated with these research objectives is an educational program targeted at K-12 students and early undergraduates, focused on increasing interest and achievement in materials science and chemistry, especially related to applications in energy and sustainability, through activities and outreach programs at local high schools and an intensive materials chemistry bootcamp to prepare new undergraduates for research positions. 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.