Machine vision is increasingly limited by the physical separation between photon capture, memory, and computation, a bottleneck visible in conventional CMOS imagers whose energy and latency are dominated by data movement rather than visual inference. Against this backdrop, this review reframes recent progress in optoelectronic memristors, photosynapses, in-sensor processors, spectral pixels, tunable photodetectors, and photonic physically unclonable devices as a broader transition in which the photodetector evolves from a passive photon to electron transducer into an information processing element. We organize the literature around three coupled questions, namely what these devices can now perform, what fundamental limitations still prevent deployment beyond silicon based digital vision, and what design strategies may overcome them. Across platforms ranging from van der Waals semiconductors, halide perovskites, and wide-bandgap oxides to III nitride heterostructures, ferroelectric and phase change materials, organic systems, and bioinspired composites, a common trajectory emerges. Progress is no longer defined by isolated synaptic curves and record responsivities but by four coupled requirements, that is, a measurable internal state variable, a verified in-device visual primitive, a quantified system-level advantage, and a credible path to scalable back-end-of-line integration, together defining a CMOS integrated cognitive pixel for next-generation machine vision.
Sodium-ion batteries (SIBs) offer an attractive platform for large-scale electrochemical energy storage, yet reliable operation at subzero temperatures remains limited by coupled transport, interfacial, and electrode-kinetic constraints. As temperature decreases, electrolyte phase instability and reduced molecular mobility restrict bulk Na+ transport, while changes in solvation structure, slower interfacial charge transfer, hindered Na+ migration through the SEI/CEI, and reduved solid-state diffusion increase polarization and can accelerate interphase evolution and Na plating. This review develops a mechanism-oriented framework linking electrolyte composition and Na+ solvation chemistry to these low-temperature failure processes. We examine how salt identity, solvent chemistry, concentration, and additives regulate ion association, bulk transport, solvation-shell reorganization, interphase formation, and electrode compatibility. Recent electrolyte-engineering strategies are critically compared, including carbonate, ester, ether, and fluorinated solvent design, single and multi-salt chemistries, multifunctional additives, high and low-concentration formulations, localized high-concentration electrolytes, and high-entropy or temperature-adaptive solvation. Particular attention is given to electrode–electrolyte matching and to the distinction between practical full-cell evidence and mechanistic Na-counter-electrode studies. By connecting composition, solvation, transport, interphase evolution, and electrode-specific failure, this review provides design principles for developing safe and kinetically accessible SIB electrolytes across subzero and wide-temperature operating conditions.
Membranes have attracted remarkable interest in gas separation technology for industrial sustainability because of their low cost and energy requirements. Their application is quite useful for gas purification and carbon capture to enable hydrogen recovery and to create a hydrogen-based society and a carbon-free future. Conventional membranes, despite being scalable and processable, suffer from a trade-off relation between permeability and selectivity defined by the Robeson upper bound limit. Metal-organic framework (MOF)/Polymer mixed matrix membranes (MMMs) have emerged as a key solution to this limitation. The synergistic combination of the MOF's high molecular sieving properties with a robust and flexible polymer has enhanced the membranes' permeability and selectivity. This review provides a detailed discussion of the membranes, their types, and the major techniques for their fabrication. We have summarised the discussion about the MOFs, their types, synthesis, and various applications and provided our opinion on their classification, synthesis techniques, and performance in the membrane-based gas separation. The review critically analysed the gas separation performance of the MOF-incorporated polymer MMMs over the last few years and discussed the current challenges that make their industrial-scale use difficult. The review concludes by discussing emerging trends, including defect engineering and 2D MOFs, which could transform the use of MOF/polymer MMMs from the laboratory to industrial scale.
The energy storage characteristics of lead-free (K,Na)NbO3-based ceramics and composite films has advanced substantially through systematic tuning of composition and processing routes, leading to substantial improvements in energy density up to ∼20 J/cm3. Despite achieving high energy densities, the simultaneous optimization of energy storage efficiency remains a critical challenge for real-time device applications. Many strategies have been developed by the researchers over the last decade to obtain simultaneous high energy density along with high efficiency in KNN-based relaxors. This review opens with a concise introduction to capacitor fundamental and then focuses on KNN-based bulk ceramics & polymer composites for energy storage applications. Specifically, it highlights strategies such as grain size reduction, enhanced microstructural homogeneity, multiple phase co-existence, high entropy, polymer composites and optimized sintering, which play a crucial role in improving dielectric polarization and breakdown strength, both of which are essential for achieving high energy density and efficiency. Moreover, we discuss the advanced characterization techniques to study the dynamic Polar Nano Regions (PNRs) and microstructure-property correlations. This review opens a new gateway for systematic synthesis of KNN-based energy storage ceramics and polymer composites to deal with the growing energy demands.
Post‑lithium metal‑sulfur batteries, especially magnesium‑sulfur (MgS) and aluminum‑sulfur (AlS), have emerged as promising candidates for next-generation energy storage due to their high theoretical energy density, low cost, and material abundance. Despite these advantages, their practical deployment is hindered by sluggish sulfur/sulfide conversion kinetics, dendrite growth at the anode surface, and the polysulfide shuttle effect. Recent advances in electrocatalyst design, such as transition metal compounds, single-atom catalysts, and composite materials have shown significant potential to accelerate conversion reactions and suppress polysulfide migration. In situ and operando spectroscopic techniques, including Raman and Fourier-transform infrared (FTIR) spectroscopy, provide real-time insights into polysulfide bonding evolution and catalyst functionality while maintaining battery operating conditions. Complementary density functional theory (DFT) calculations further elucidate adsorption energies, charge transfer, and Gibbs free energy profiles, guiding rational catalyst design. This review summarizes the advantage of combining in situ spectroscopy with electrochemical characterization techniques and the recent progress in in situ Raman and FTIR studies of electrocatalytic mechanisms in MgS and AlS batteries.
