Freestanding inorganic oxide films for flexible electronics

Recently, flexible electronic devices are of increasing interest due to their wide range of application fields, including information storage, energy conversion, and wearable and implantable electronics. In particular, freestanding inorganic oxide films are proved to be an extraordinary versatile platform for flexible electronics owing to their super elasticity, outstanding functionalities, tunability, and long-term stability. In this Perspective, we review the up-to-date advances of freestanding inorganic oxide films from the perspectives of synthesis methods, physical properties, and device applications. First, preparation strategies based on epitaxial lift-off technologies are classified into physical and chemical aspects that are to be introduced. Second, we discuss the physical properties of freestanding inorganic oxide films, especially in terms of ferroelectricity, magnetism, multiferroics, etc. Third, we highlight several device applications in the fields of data memory, energy storage, and health care. Finally, we conclude with a future perspective into prospects and challenges regarding the syntheses and applications of freestanding inorganic oxide films.