Research Progress on Transparent Conductive Properties of SnO2 Thin Films

As a core candidate material for indium-free transparent conductive oxides, tin dioxide (SnO2) thin films are gradually replacing indium tin oxide (ITO) and becoming a research focus in the field of optoelectronic devices, thanks to their excellent physicochemical stability, wide bandgap characteristics, and abundant tin resource reserves. This review focuses on SnO2 thin films. Firstly, it elaborates on the tetragonal rutile crystal structure characteristics of SnO2 and the transparent conductive mechanism based on oxygen vacancies and doping elements to regulate free electron concentration, while clarifying the key parameters for evaluating their transparent conductive properties. Subsequently, it systematically summarizes the research progress in preparing SnO2 transparent conductive thin films via physical methods and chemical methods in recent years. It compares the microstructure and transparent conductive properties of thin films prepared by different methods, and analyzes the regulatory laws of preparation processes, doping types, and film thickness on their optoelectronic properties. Furthermore, this work supplements the current application status of SnO2 thin films in devices. Meanwhile, the core performance differences between indium-free tin-based thin film devices and ITO-based devices are compared. Finally, we have summarized the advantages and challenges of physical and chemical methods in the preparation of SnO2 thin films. It also forecasts the application potential of interdisciplinary integration of physical–chemical methods and the development of new doping systems in the preparation of high-performance SnO2 transparent conductive thin films. This review aims to provide theoretical guidance and technical references for the selection and process optimization of SnO2 transparent conductive thin films in fields such as photovoltaic devices and flexible optoelectronic equipment.