Ferroelectric photovoltaic (FPV) materials represent a distinctive category of multifunctional materials that integrate spontaneous electric polarization with photovoltaic functionality. This dual functionality makes them highly promising for next-generation energy technologies, especially in applications involving solar energy conversion and integrated storage. This review provides recent advancements in FPV materials, covering fundamental mechanisms, synthesis methods, material engineering, and device integration. Emphasis is placed on perovskite oxides, organic–inorganic hybrids, lead-free ferroelectrics, and 2D materials, highlighting their photovoltaic performance, dielectric properties, and suitability for self-powered systems. Strategies to optimize FPV efficiency, such as domain engineering, architecture optimization, and heterostructure interfaces, are examined. This review also explores cutting-edge developments in tandem solar cells, hybrid energy systems, and multifunctional devices that bridge the gap between energy harvesting and storage. Critical challenges – including wide bandgaps, low conductivity, instability, and scalability, are analyzed, alongside current challenges and future directions in the field of FPV materials for energy applications. It highlights the need for further research on stability, scalability, and cost-effective solutions through novel materials and device architectures.
Following the Fukushima Daiichi accident, considerable effort has been directed toward accident-tolerant fuel claddings that can provide larger safety margins during normal operation, transients, and loss-of-coolant accidents. MAX phases, including Ti3SiC2, Ti2AlC, Cr2AlC, and Zr2AlC, have attracted interest for this purpose because they combine relatively high thermal conductivity, good mechanical strength, damage tolerance, and resistance to oxidation and irradiation. However, their behavior in light-water reactor environments is still not fully understood. In particular, questions remain regarding corrosion in reactor primary water, bonding and compatibility with zirconium alloys, irradiation-assisted degradation, and the feasibility of industrial-scale fabrication. This review discusses MAX-phase coatings and bulk MAX-phase cladding concepts for light water reactors, with particular attention paid to corrosion in a simulated primary coolant at 300–330 °C, where long-term performance strongly depends on the formation and stability of protective oxide scales. The reported degradation mechanisms and thermo-mechanical issues associated with coating zirconium substrates are examined. The performance of MAX phases is also compared with that of other candidate cladding materials in terms of oxidation kinetics, radiation resistance, fabrication routes, mechanical properties, and technological maturity. Multilayer coatings based on MAX phases combined with chromium or silicon layers are also discussed. Important open questions remain, particularly regarding hydrothermal degradation, radiation-damage evolution, and diffusion at the coating-substrate interface.
One-dimensional photonic crystals (1D PhCs) are among the most fundamental building blocks of modern photonic devices owing to their simple, lithography-free architecture, ease of fabrication, and versatile optical properties. Their optical response can be reconfigured through external stimuli such as the angle of incidence, temperature, pressure, electric fields, and magnetic fields. While such tunability is advantageous for active photonic applications, uncontrolled variations can cause undesirable spectral shifts and performance degradation, creating challenges for stable device operation. This review surveys recent strategies developed to reduce the incident-angle dependence in 1D PhCs, covering their theoretical foundations, design approaches, and applications. It discusses angle-independent photonic band gaps (PBGs) and confined modes in conventional and topological 1D PhCs hybridized with anisotropic layers, with emphasis on effective medium theory and phase-compensation mechanisms. Furthermore, coupled-resonance phenomena and emerging quantum-inspired optical effects are reviewed, highlighting their underlying mechanisms and potential photonic applications. Finally, current challenges and future opportunities for robust, angle-independent photonic devices are discussed.
Hydrogel technologies have rapidly evolved from simple hydrated materials to multifunctional systems for soft robotics, drug delivery, tissue engineering and surgical simulation. As their complexity increases, designing hydrogels for a specific application requires identifying which mechanical phenomena govern material behaviour under the relevant operating conditions, rather than optimising individual properties in isolation. In this Review, we propose a regime-based mechanical perspective to organise hydrogel mechanics around the physical mechanisms that dominate under different functional scenarios. After introducing a minimal mechanical framework, we examine representative applications to show how elasticity, swelling, solvent transport, viscoelasticity, fracture and mechanical instabilities become alternatively dominant depending on geometry, loading conditions and characteristic timescales. This approach provides a physical framework for identifying the mechanical aspects that should guide material design in different applications, offering a unified strategy for understanding hydrogel behaviour and supporting the rational development of future multifunctional systems.
Copper-based metal-organic frameworks (Cu-MOFs) offer several benefits, including routes for ion diffusion and adsorption sites for ions from the electrolyte, owing to their large surface area, porosity, structural configurations, and composition. Recent advancements in this area highlight the potential to achieve high energy and power densities, improved cycle stability, and enhanced energy-storage capabilities in high-performance supercapacitors (SCs) using Cu-MOFs and their composites. Selecting appropriate metal ions and organic ligands for the MOFs enables tailoring of their conductivity, redox properties, surface area, functionality, stability, and porosity. Several approaches can be used to improve their electrochemical performance by synthesizing derivatives and composites incorporating metal oxides, chalcogenides, carbon, and conducting polymers. This review highlights recent advances in Cu-MOFs as potential SC electrodes and examines their structures, electrochemical processes, and potential for hybrid SCs. The review outlines key strategies to improve the electrochemical performance of Cu-based electrodes, including structural modification, compositional optimization, and composite design. While MOFs show substantial promise, challenges remain regarding economic feasibility, complex synthesis processes, scalability, and cyclic stability, all of which are summarized. Finally, it identifies current challenges and offers insights into the future development of Cu-based MOFs for SCs.
