Zhen Zhang

Thermal management by controlling radiative energy exchange has emerged as a sustainable route for regulating temperature and reducing energy consumption. Conventional thermal–management surfaces with static optical properties continue to find it challenging to respond to dynamic changes in ambient temperature, solar irradiation, or operating conditions. Strongly correlated oxides, which undergo insulator–metal transitions under external stimuli such as heat, electric field, light, or ion intercalation, enable reversible modulation of their optical constants for dynamic control of radiative energy exchange. This review summarizes recent advances in utilizing insulator–metal transitions in correlated oxides for dynamic thermal management. We first describe the energy balance of adaptive thermal surfaces within the solar and atmospheric spectra and map the optical parameters of materials to device–level thermal regulation performance. Then, three representative correlated oxides, including tungsten trioxide, vanadium dioxide (VO₂), and perovskite rare–earth nickelates (RNiO₃), are discussed in their transition behaviors and optical responses across multiple wavelength regions. Next, the design strategies and performance of devices based on these correlated oxides are surveyed with emphasis on smart windows, radiative cooling coatings, and emerging applications. Finally, we outline current challenges and future directions of correlated oxide–based dynamic thermal management.

Hydrogenation of perovskite rare-earth nickelates induces giant lattice distortions and enhanced tilting/rotation of NiO6 octahedra, enabling a room-temperature metal–insulator transition. However, unraveling the couplings between ion, electron, and lattice degrees of freedom introduced by hydrogenation remains a significant challenge. In this work, we investigate the electronic dynamics of gradient hydrogen-doped correlated NdNiO3 (NNO) film using broadband femtosecond transient reflectivity spectroscopy. It is found that the incorporation of hydrogen suppresses the phonon-polariton beats in pristine NNO while a biexponential decay process appears in lightly hydrogen-doped NNO. The additional relaxation channels introduced by hydrogen compete with the bottleneck effect mediated by bandgap opening, which would affect the ultrafast electronic dynamics. Meanwhile, the markedly accelerated slow relaxation in heavily hydrogen-doped NNO is consistent with nonradiative recombination mediated by impurity defect states. These results reveal that hydrogen incorporation not only modifies the equilibrium electronic structure of NdNiO3 but also acts as an ionic control knob for reshaping nonequilibrium carrier relaxation pathways. This work extends hydrogen-controlled nickelate physics from static phase modulation to ultrafast carrier dynamics, highlighting hydrogenation as a powerful strategy for engineering relaxation timescales and recovery pathways in correlated-oxide iontronic devices.

The human brain is a natural computing platform composed of a vast number of neurons and synapses that excels in learning, memory, and parallel data processing with low energy consumption and high efficiency. Brain‐inspired hardware is crucial in the application of neural networks, offering enhanced energy efficiency, parallel processing capabilities, and nonlinear dynamic properties, such as adaptability and plasticity. Complex oxides exhibit rich electrically metastable states, which enable diverse resistive switching dynamics in response to electrical stimuli. This allows them to achieve complex bioinspired behaviors at the single‐device level and more advanced brain‐like functions through multidevice integration. This review summarizes recent advances in resistive switching of complex oxides with a focus on the underlying physical mechanisms and application‐driven device‐algorithm co‐design. It first elucidates the materials science and multiscale mechanisms of the switchable electrical characteristics of complex oxides. Next, the resistive switching behaviors of complex oxide devices and a survey of their state‐of‐the‐art performance are discussed. Additionally, from the perspective of brain‐inspired computing, device‐level biomimetic applications and task‐driven circuit‐algorithm co‐designs are explored. Finally, the current challenges of complex oxide devices are summarized, and an outlook for the development of complex oxide neuromorphic devices is provided.

Active switching, which enables multifunctionality within a single optical component, is essential for reconfigurable infrared photonic systems such as radiation engineering, sensing, and communication. Metamaterials offer a solution but involve complex design and fabrication. A simpler approach with a planar layered structure becomes promising for offering economical manufacturing, easier integration, and scalability. However, it requires an active medium with giant tunability and effective modulation mechanisms. Here, an electrically controlled reversible infrared switching is demonstrated via a single layer of perovskite nickelate on an opaque substrate. Driven by the evolution of the refractive index during an electrically triggered proton‐mediated metal‐to‐insulator transition, the device transforms from a high reflective (R ≈0.74) to a low reflective state (R ≈0.09) at λ = 7–10 µm. A temperature‐independent perfect absorption (A > 0.99 at λ = 11.6–12.1 µm) emerges in the partially hydrogenated state with the mixture of the metal and insulator phases, which results in a modulation of emissivity ≈0.623 at λ = 7–14 µm. The switching behavior is tunable over a wide temperature and wavelength range, offering a versatile path for adaptive infrared applications.

The layered van der Waals CuInP₂S₆ (CIPS) features interesting functional behaviors, including reversible ferroelectric polarization, Cu ion migration, negative capacitance effect, etc. Here, the CIPS flakes were exfoliated from the CVT-grown high-quality single crystals, which were fabricated into metal/CIPS/metal heterostructures by conventional photolithography. It was found that the CIPS flakes persisted in the dominant out-of-plane polarization and the minor in-plane polarization. Clear hysteresis current–voltage (I–V) loops, as well as the rectifying character, were revealed in metal/CIPS/metal heterostructures, indicating the potential application as a memory device. Additionally, the different metal electrode could significantly modulate the Schottky-like barrier at metal/CIPS interfaces, resulting in symmetric or asymmetric I–V loops. The complicated I–V curves may have originated from the voltage-induced Cu ion migration, reversible ferroelectric polarization, and carrier (ion) trapping/detrapping. This work may facilitate the metal electrode selection for the ferroelectric CIPS-based device application.

Perovskite nickelates belong to a family of strongly correlated materials, which have drawn broad attention due to their thermally induced metal-to-insulator transition. Recent discoveries show that orbital filling mediated by ion intercalation can trigger a colossal non-volatile conductivity change in nickelates. The coupling and interaction between two types of charge carriers (i.e., ions and electrons) enable nickelate as an exotic mixed conductor for electronic, biological, and energy applications. In this Perspective, we first summarize the fundamentals and recent progresses in the manipulation of ground states of perovskite nickelates by controlling orbital filling via ion intercalation. Then, we present a comprehensive overview of perovskite nickelate as a unique platform for vast cutting-edge research fields, including neuromorphic computing, bio-electronic interfaces, as well as electrocatalysis applications by taking advantage of such electron-filling-controlled modulation phenomena. Finally, we provide an overview of future perspectives and remaining challenges toward the exploitation and commercialization of quantum nickelates for future multidisciplinary research.