Multiscale electronic structure engineering of transition metal oxides: From atomic-scale, mesoscale, and external-field manipulation to multifunctional applications

Transition metal oxides (TMOs), with their highly tunable charge, spin, orbital, and lattice degrees of freedom, represent a versatile class of materials central to energy, catalytic, electronic, and biomedical applications. Electronic structure engineering serves as a critical approach to modulating the properties of TMOs, with significant advancements recently achieved at atomic-scale precision, mesoscopic structural design, and external-field stimulation. However, current research predominantly focuses on single-dimensional modulation, lacking a systematic understanding of the coupling mechanisms among multi-scale strategies and their structure-property correlations. This review adopts a mechanism-centric perspective to comprehensively outline the modulation pathways of TMOs’ electronic structures across atomic-scale strategies (doping, defects, strain), mesoscale architectures (heterointerfaces), and external-field stimuli (light, electricity, magnetism, heat). Special emphasis is placed on elucidating their mechanistic roles in governing charge transfer, spin polarization, orbital reconstruction, and band structure evolution. Furthermore, we construct a functional landscape linking multi-scale electronic structure modulation strategies with performance responses, spanning three interdisciplinary application domains: energy, information technology, and life sciences. This framework provides a transferable methodological paradigm for material design across different length scales. Finally, we highlight key challenges that remain to be addressed in multi-scale electronic structure engineering and discuss future research directions. Our review aims to provide systematic insights and technical guidelines for the structural regulation and high-performance integration of TMOs and related functional materials.