Connecting the Physical Properties of Chalcopyrites to Their Performance in Solar Energy Applications

Abstract

The chalcopyrite phase of ternary transition metal chalcogenides is an important family of materials for their ability to harness solar energy to generate electricity or fuel which offers the opportunity for sustainable energy production. This work provides a unique combination of physical property analysis and solar harnessing experimentation to explore the intimate connection between the fundamental properties of chalcopyrite materials and their performance in solar energy-harvesting applications.

Chapter 1 serves as the necessary foundation to understand this work: section 1.1 defines ternary transition metal chalcogenides and their chalcopyrite crystal structure; section 1.2 reviews the basics of semiconductor physics; and section 1.3 describes the four general steps used to execute the projects described in Parts I, II, and III.

Parts I, II, and III are divided by the chalcopyrite material of focus—CuIn(S1-xSex)2, CuInTe2, and CuInS2, respectively. Part I follows the polycrystalline synthesis and electrode fabrication of CuIn(S1-xSex)2 (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) for photoelectrochemical evolution of H2 and CO2 reduction. Part II follows the single crystal growth of CuInTe2 and its characterization as a potential candidate for photoelectrochemical solar fuel production through thermodynamic photoelectrode analysis and electronic band structure studies. Part III follows the single crystal growth of CuInS2 and analysis by electronic transport measurements, atomic-scale imaging, and photoexcitation experiments to interpret the source of detrimental metastability reported in chalcopyrite photovoltaic devices.