Unique chemistries of metal-nitrate precursors to form metal-oxide thin films from solution: materials for electronic and energy applications

Metal-oxide thin films are used extensively in electronic and energy applications. Solution processing offers a potentially scalable and inexpensive deposition method to expand the applications of metal-oxide films and to complement vacuum-deposition techniques. Among precursors for solution deposition, metal nitrates stand out for their ability to form high-quality metal-oxide thin films. This review focuses on unique aspects of metal-nitrate chemistry that have been exploited to advance the development of solution-processed thin films. We discuss the solid-state bulk, solution, and thin-film chemical reactions involving metal nitrates and illustrate how the resulting metal-oxide thin-film properties depend on the entire reaction pathway. To conclude, we offer perspective as to how understanding the chemistry of film formation from metal-nitrate precursors is useful for addressing the primary drivers for industrial manufacturing of solution-processed metal-oxide thin films.