Influence of Precursor Solution Composition on the Electrical Properties of Solution-Processed Indium Tin Oxide Thin Films

Solution-based processes have emerged as a compelling alternative to the traditional vacuum-based physical vapor deposition to fabricate indium tin oxide (ITO) films owing to their advantages of cost-effectiveness, being vacuum-free, and simple equipment. Despite extensive research to improve the electrical properties of ITO films as transparent conductive oxides (TCOs), the influence of precursor solution composition on these properties remains unexplored. Here, we prepare precursor solutions that vary in anionic groups and metal cation valence states and investigate how the composition of these solutions influences the electrical properties of the solution-processed ITO films. The results reveal that incorporating nitrate anion-based precursors and Sn (II)-based precursors in the solutions leads to the ITO film with a low resistivity of 3.5 × 10 –3 Ω cm. This performance is attributed to the abundant formation of M-O-M bonds and the appropriate concentration of oxygen vacancies in the polycrystalline ITO films. Thin film transistors utilizing ITO patterns with reduced resistivities demonstrate enhanced field-effect mobilities, which can be attributed to the decreased contact resistances between the ITO source/drain electrodes and indium oxide channels. The practical application of patterned ITO films in flexible electroluminescent devices is demonstrated, highlighting the immense potential of using our ITO films in optoelectronic and flexible technology.