University of California, Santa Barbara
Faculty Sponsor's Department(s):
Chemistry and Biochemistry
Synthesis and Preparation of Uranium Oxides for Thin Film Photovoltaics
Metal oxide semiconductors are widely used in photovoltaic applications and uranium (IV) dioxide (UO2) has a high potential in this field due to its favorable band gap and conductivity and its high operating temperature. However, the commonly used chemical vapor deposition (CVD) is not ideal due to the high melting and boiling point of UO2 and the synthesis must be specific so that other insulating uranium oxides that would impact the PV cell performance are not present. Our lab is investigating low temperature, solution processable synthesis pathways of UO2 that allow for sol-gel deposition to get around this challenge. We have chosen a few key ligand designs and are experimenting with both oxygen and nitrogen based ligand uranium complexes as starting materials since these factors greatly increase the compound’s solubility range and change the reaction mechanism. Specifically, we are using ditox and bis(trimethylsilyl)amides to form uranium alkoxides and uranium amides, respectively, in organometallic Grignard reactions. Following this with a series of purification steps, hydrolysis, and various thin film coating methods, our lab aims to synthesize pure UO2 films. We are also investigating the impact of fluorinating the ligands to make the compound sublimable and subliming a metallacycle intermediate to lead to UO2 films accessible by CVD.