This review focuses on recent progress in defect-engineered novel functionalities of complex oxide thin films for electronics and energy applications, and current challenges and perspectives.J.L.M.-D. also acknowledges support from the Royal Academy of Engineering, Grant CiET1819_24, and the ERC POC grant, 779444, Portapower. K.H.L.Z. is grateful for funding support from the National Natural Science Foundation of China (Grant No. 21872116)
