SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3773-7
Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) solar cells suffer from significant open-circuit voltage (VOC) deficits due to severe interfacial and bulk recombination, restricting their power conversion efficiency (PCE) far below the Shockley-Queisser limit. This work proposes a low-temperature annealing strategy during ITO sputtering (SA) to synergistically address these challenges. The temperature applied during ITO sputtering not only improves the crystallinity, carrier concentration, and optical transmittance of the ITO layer but also promotes the diffusion of In from ITO into both CdS and CZTSSe layers. Consequently, lattice matching at the CZTSSe/CdS interface is optimized, enabling epitaxial growth. And a favorable ITO/In:CdS/In&Cd:CZTSSe structure with optimal band alignment is obtained. As a result, a champion device with a PCE of 14.29% was achieved. The SA-treating also enabled the CZTSSe solar cells to achieve the highest VOC reported to date, exceeding 590 mV. This underscores the essential role of SA processing in optimizing interface engineering and suppressing defects, thus promoting the development of low-cost, high-performance kesterite photovoltaics.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3633-5
High-temperature interfacial diffusion in Half-Heusler (HH) thermoelectric devices poses significant challenges for practical applications, particularly the diffusion of Ag from conventional solders, which degrades material performance and device stability. This study reveals anomalous Ag diffusion through a Cr powder barrier layer into Ti0.5Zr0.5NiSn0.98Sb0.02, driven by Sn phase penetration. In contrast, employing a Cr foil barrier layer pre-densified the material, effectively preventing Sn phase penetration and eliminating Ag diffusion pathways, thereby preserving junction integrity. After aging at 973 K for 30 days, the Cr foil junction maintained a clean interface with a low contact resistivity of 0.27 μΩ cm2. Benefiting from this interfacial design, a Hf-free HH module achieved a high conversion efficiency of 10.4% at a hot-side temperature of 976 K, alongside long-term stability. This work addresses critical bottlenecks in developing high-performance, low-cost HH modules, facilitating their commercial application in waste heat recovery.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3931-6
Detection of circularly polarized light (CPL) is crucial for advancing next-generation chiral optoelectronic applications, where a large photocurrent dissymmetry factor (g_Iph) is essential for accurate polarization discrimination. Chiral hybrid perovskites (CHPs) have emerged as promising CPL-active materials owing to their intrinsic spin-orbit coupling and chiroptical properties. However, an intrinsic conflict between g_Iph and photocurrent response remains a major bottleneck in current CHP-based devices. Low-dimensional CHPs typically suffer from limited carrier mobility, while multilayered structures improve carrier transport but generally reduce the chiral component, thereby reducing chiroptical activity and g_Iph. Herein, we report a Cs-based multilayered chiral-polar perovskite, (R-β-MPA)PACsPb2Br7 (1R, MPA=methylphenethylammonium, PA=propylammonium). The distinctive chiral-polar photovoltaic effect in 1R benefits spin-selective carrier separation and collection, and the resulting device achieves self-powered CPL detection with a high g_Iph of 0.5 and maintains excellent polarization selectivity even at ultralow light intensities of 62 nW cm−2. Meanwhile, the multilayered framework enables high responsivity of 71 mA W−1 and detectivity of 6×10^12 Jones (1 Jones = 1 cm Hz^(1/2) W−1) even at zero bias. This work provides a rational design strategy to achieve chiral optoelectronic materials with a high dissymmetry factor and photocurrent response.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4012-4
Stimuli-responsive fluorescent hydrogels, owing to their tunable optical properties and unique smart response characteristics, have significant potential in encryption applications and information security. However, most current systems are limited to single-stimulus responsiveness and lack the capability for programmable information erasure or multi-modal dynamic synergy. Hence, we propose a multi-stimuli-responsive phase-change hydrogel incorporating aggregation-induced emission hydrophobic carbon dots (AIE-HCDs) and polyethylene glycol (PEG)-cellulose network, demonstrating dynamic fluorescence chromism under various external triggers. The hydrogel exhibits solvent-exchange-triggered fluorescence color changes from blue to red, enabled by the concentration modulation of AIE-HCDs through the exchange between PEG and water. Additionally, the temperature-induced phase transition of PEG from crystalline to molten state modulates the aggregation and dispersion of AIE-HCDs, thereby enabling dynamic fluorescence color changes. The phase transition further confers excellent shape-memory behavior and adjustable mechanical properties, with the tensile modulus varying from 6.28 MPa in the molten state to 36.23 MPa in the crystalline state, while maintaining high transparency (~88% in the molten state). By utilizing micro-contact printing and the multi-stimulus response, an encryption platform enables information to be hidden, selectively read under sequential stimuli (thermal, UV, and solvent), and completely erased upon demand. This strategy demonstrates significant potential for advancing high-level information encryption and anti-counterfeiting technologies.
Environmental Chemistry•2026•DOI: 10.7524/j.issn.0254-6108.2025041505
To combat severe air pollution, China has implemented a series of air pollution control action plans since 2013, effectively alleviating PM2.5 pollution. However, PM2.5 concentrations in most cities within the Fenwei Plain still exceed national standards. This study systematically evaluates PM2.5 concentration changes across two policy phases (2013–2020) using the Community Multiscale Air Quality (CMAQ) model, quantifying contributions of meteorology and emissions, and analyzing sectoral source changes. Results show that annual average PM2.5 concentration declined cumulatively by 19% during 2013–2020. In the first phase (2013–2017), regional PM2.5 decreased by 3% annually, with most improvement in winter; however, due to unfavorable meteorology, concentrations increased in Xi'an and Xianyang. In the second phase (2017–2020), PM2.5 declined by an additional 16%, with more effective control measures, particularly in spring and autumn. Emission reductions dominated in both phases, with stronger effects in the second phase (−8 μg·m−3), significantly outweighing adverse meteorological contributions (+3.5 μg·m−3). Nevertheless, many cities still face challenges from unfavorable meteorology, highlighting the need for future policies to account for meteorological influences. Emissions from industrial, energy, and agricultural sources decreased significantly across both phases. However, during winter heating periods, residential emissions emerged as a source equal in importance to industrial emissions, becoming a key target for future emission controls.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4144-y
Developing efficient strategies for electrically manipulating two-dimensional magnetism at room temperature is a key challenge in contemporary spintronics. In this study, we demonstrate giant electromechanical control over the magnetism of the room-temperature van der Waals ferromagnet Fe3GaTe2 by integrating it with the ferroelectric α-In2Se3. Modest gate voltages lead to an almost complete suppression of the coercive field by 96.5%, corresponding to a remarkable peak modulation sensitivity of ~8.1 mT V−1, which stands out among existing van der Waals magnetoelectric systems. Importantly, this substantial magnetoelectric response is predominantly unaffected by voltage polarity, as both positive and negative gate voltages induce similar magnetic modulation effects. To elucidate the underlying mechanism, we tracked the voltage-induced Raman spectral changes, revealing a peak shift of 1.7 cm−1 that accurately represents an effective in-plane tensile strain of ~1.42% under an equivalent bias, demonstrating polarity independence as well. The synchronized magnetic response and strain variation unequivocally indicate that the induced tensile strain serves as the fundamental physical driver behind the magnetic modulation. Additionally, density functional theory calculations corroborate that the reduction in magnetic anisotropy induced by tensile strain results in a decrease in the coercive field. Our work establishes a novel and efficient approach for achieving voltage control of magnetism at room temperature in van der Waals multiferroic heterostructures, highlighting their significant potential for applications in ultra-low-power magnetic logic and sensing technologies.