SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4494-9
Superionic conductors exhibit high cation mobility arising from weak binding and continuous transport pathways, atomistically characterized by extensive structural disorder and partial occupancy akin to amorphization. This disorder, whether confined to a cation sublattice or extended to full amorphization, strongly impedes lattice thermal transport, rendering these materials intrinsically ideal thermal insulators. This work investigates Ag26I18W4O16, a superionic conductor tunable from fully amorphous to single-crystalline states, as a model system to probe the impact of disorder and amorphization on thermal transport. Extensive Ag+ disorder, in both crystalline and amorphous phases, reduces thermal conductivity to approximately the theoretical lower bound of 0.16 W/m-K with virtually no temperature dependence, while concurrently achieving the lowest mean sound velocity ever recorded for a dense solid. Pair distribution function (PDF) analysis of synchrotron X-ray total scattering data indicates that short-range disorder (< 5 Å), rather than long-range periodicity, governs thermal insulation performance in both phases. These findings suggest a design strategy reconciling structural stability with glass-like thermal insulation.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-026-4106-8
Perovskite/organic tandem solar cells (PO-TSCs) have emerged as a compelling photovoltaic architecture to transcend the Shockley-Queisser limit of single-junction devices. By monolithically stacking a wide-bandgap (WBG) perovskite top cell and a narrow-bandgap (NBG) organic bottom cell, PO-TSCs enable broad spectral utilization and reduced thermalization loss, offering a viable pathway toward efficiencies beyond 30%. Their solution processability, compatibility with orthogonal solvents, and potential for lightweight, flexible, and semi-transparent modules further make them attractive for building integrated and portable electronics. However, the realization of high-performance PO-TSCs critically depends on precise carrier regulation across the entire multilayer stack, where inefficient charge transport, recombination losses, and interfacial bottlenecks often limit the overall power conversion efficiency (PCE) and stability. This review systematically examines the carrier-regulation strategies essential for advancing PO-TSCs, focusing on defect and phase-control in WBG perovskites, the design of optically transparent and electrically efficient interconnecting layers, and the enhancement of charge generation and collection in organic subcells. The integration of these approaches has recently enabled efficiencies exceeding 26%, demonstrating the rapid progress of the field. Ultimately, we conclude with an outlook on the remaining challenges in scalability, operational stability, and manufacturability, providing a roadmap for future research toward commercially viable tandem photovoltaics.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3599-5
Layered transition metal tellurides (TMTs) are promising cathode materials for aqueous zinc ion batteries (AZIBs) due to their graphite-like layered structure and weak van der Waals interactions, which facilitate rapid ion transport. However, their holistic performance—specific capacity, rate capability, and cycling stability—remains insufficient for practical applications. Here, we report a straightforward NaBH4-assisted chemical etching method to introduce abundant Te vacancies on the surface of Bi2Te3 (denoted H-Bi2Te3). Experimental and theoretical analyses reveal that these Te vacancies refine the band structure, enhance electrical conductivity, and significantly reduce the diffusion barrier for Zn2+ ions. Additionally, the vacancies provide increased storage sites for Zn ions. Consequently, H-Bi2Te3 exhibits superior zinc storage performance: a high Zn2+ diffusion coefficient of 3.98×10−11 cm2 s−1, a specific capacity of 325 mAh g−1 at 0.1 A g−1, a rate capability of 217 mAh g−1 at 1 A g−1, and exceptional cycling stability with 70 mAh g−1 retained after 10,000 cycles at 1 A g−1. This work introduces a novel vacancy defect engineering strategy for TMT-based cathodes in AZIBs and expands the potential applications of vacancy-rich TMT materials.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4082-6
High-performance nonvolatile memory devices are crucial for next-generation computing, yet achieving low-power, stable, and reproducible resistive switching remains challenging, primarily due to stochastic filament formation and limited precise control over the electronic properties of active materials. Herein, we employ a rational molecular engineering strategy to address these limitations by constructing a series of two-dimensional pyrene-based covalent organic frameworks (Py-COFs)—Py-H, Py-CH3, and Py-OH—via systematic substitution (–H, –CH3, and –OH) on the phenyl linkers to modulate backbone electronics. The electron-donating –CH3 and –OH motifs enrich the π-conjugated backbone with higher electron density, while the –OH moiety in Py-OH further engages in p-π conjugation with the benzene ring and forms intramolecular hydrogen bonds, thereby increasing framework rigidity, enhancing orbital overlap, and promoting charge delocalization. Enabled by these structural refinements, Py-OH-based devices exhibit markedly improved resistive switching behavior, characterized by a low operating voltage, an ON/OFF ratio of ~10^3.45, and excellent retention stability. Combined photophysical, electrochemical, and high-resolution TEM analyses corroborate that hydroxyl-driven p-π conjugation, hydrogen-bond reinforcement, and the emergent nanowire-like morphology synergistically suppress uncontrolled filament formation and promote efficient charge transport. These findings establish a clear structure-property correlation in functionalized Py-COFs and underscore their promise as tunable active layers for low-power, high-performance resistive memory and neuromorphic computing.