Bridging the gap between molecular-scale photochemical reactions and programmable macroscopic motions represents a fundamental goal and a significant challenge in the field of crystal engineering. Herein, we present a rational design strategy for controlling the photomechanical responses of anthracene-based crystals through systematic molecular packing engineering. By tailoring the steric and electronic properties at the C1/C8 positions of the anthracene backbone and employing directional perfluoroarene–arene interactions, we achieve precise control over both the spatial arrangement of photoreactive dimers and the strength of the interaction network. This strategy enables predictable access to three distinct photoactuation modes—coherent expansion, violent ejection, and regular fracture—all of which are driven by a single [4+4] photocycloaddition. Structural, spectroscopic, and computational analyses demonstrate that the specific actuation pathway is determined by the interplay between dimer alignment and intermolecular interactions, which directs how reaction-induced stress propagates through the crystal lattice. Furthermore, the controlled fracture enables the photochemical cleavage of bulk crystals into microscale rods that retain their structural integrity and function as optical waveguides. This work establishes a clear structure–property relationship for programming photomechanical functions from the molecular level upward, showcasing the potential of crystal engineering to create adaptive and multifunctional materials.

ABSTRACT Ag2Se is a promising n‐type thermoelectric for near‐room‐temperature applications. Nevertheless, further enhancement of its figure of merit (ZT) demands a delicate balance between electronic and phononic transport. Here, we develop a facile and controllable wet‐chemical strategy under ambient conditions to synthesize orthorhombic Ag2Se nanocrystals. Indium substitution at the Ag site modulates the electronic structure, leading to a Fermi‐level upshift, band‐gap narrowing, and increased carrier concentration, thereby enhancing electrical transport. Meanwhile, In's incorporation introduces local dislocations and anisotropic strain fields that induce lattice softening and reduce the sound velocity, resulting in enhanced phonon scattering and suppressed lattice thermal conductivity. First‐principles calculations further reveal that In incorporation weakens Ag─Se antibonding interactions and suppresses Ag s‐d hybridization in favor of In s‐p hybridization, thereby mitigating potential fluctuations and enhancing carrier mobility. Benefiting from this synergistic phonon‐electron optimization, Ag1.9287In0.0713Se achieves a high power factor of ∼3100 µW m−1 K−2 and a peak ZT of ∼1.2 at 398 K. Prototype modules exhibit consistently higher output voltage and power density, while hardness mapping confirms improved lattice resilience. This work highlights the potential of coupling defect chemistry with electronic structure engineering as an effective strategy to advance high‐performance and mechanically robust Ag2Se ‐based thermoelectrics.

ABSTRACT Bismuth selenide (BiSe) is an n ‐type thermoelectrics with promising room‐temperature potential as a tellurium‐free alternative to Bi 2 Te 3 ‐based materials. It features ultralow lattice thermal conductivity ( κ lat ), but suffers from excessively high carrier concentration, yielding a low Seebeck coefficient. This remains a fundamental challenge in BiSe. Here, we introduce yttrium (Y) doping in Sb‐alloyed BiSe (Bi 0.7 Sb 0.3 Se), inducing substantial Bi vacancies to reduce carrier concentration. Experimental characterization combined with theoretical calculations demonstrates that Y preferentially substitutes Bi at the Bi 2 bilayer sites, which opens the bandgap and flattens the valence/conduction bands, thereby enhancing the band‐edge density of states (DOS) effective mass and increasing the Seebeck coefficient. This enhances power factor across a broad temperature range. Defect regulation and multiscale nanopores further amplify phonon scattering, reducing κ lat by 50% at 393 K. Consequently, Bi 0.64 Sb 0.3 Y 0.06 Se achieves a peak zT of 0.91 at 393 K and average zT of 0.76 (300 – 523 K), representing significant progress within the emerging BiSe‐based material. Furthermore, an 8‐pair BiSe‐based module achieves a conversion efficiency of 4.6% and a normalized power density of 10.8 µWcm −2 K −2 , which is expected to pave the way for BiSe‐based materials to become a realistic n ‐type thermoelectric material for sustainable applications.

High-throughput technology has proven to be an efficient approach for exploring the effects of compositional variation on material properties. Using combined laser molecular beam epitaxy technology, we successfully fabricated continuous composition films of BixSb2-xTey on a single substrate, with Sb and Bi doping levels ranging from 0.0 to 2.0, while maintaining a nearly constant Te content throughout the film. This continuous gradient of composition allows for the rapid identification of the optimal electrical transport composition, which is found to be between 0.25 < x < 0.5, while the composition range for the change in carrier type occurs between 0.8 < x < 1.05. These findings establish a foundation for determining precise quantitative relationships.

Wearable thermoelectric devices (WTEDs) have garnered significant interest for applications in personal thermal management and energy harvesting from the human body. Nevertheless, a major limitation hindering their performance is inadequate heat dissipation. To overcome this issue, this study introduces an integrated WTED architecture featuring a flexible finned heat sink based on a phase change material (PCM), which is structurally integrated with the thermoelectric unit. The heat sink is composed of epoxy-encapsulated paraffin PCM doped with high-thermal-conductivity aluminum nitride (AlN) additives, significantly enhancing the composite's effective thermal conductivity and overall thermal management capability. Experimental results validate the efficacy of this integrated design: at a temperature difference of 30 K, the device delivers an open-circuit voltage of 239.0 mV and a power output of 9212.85 mu W, corresponding to a 1386% enhancement compared to a system without the heat sink. Moreover, the integrated device demonstrates markedly improved conversion efficiency even under low temperature gradients (< 10 K), rendering it highly suitable for integration with boosting circuits in wearable electronics. Based on heat transfer optimization, this device achieves portable wearable cooling without fans or liquid cooling assistance. It provides up to a 4.4 degrees C skin temperature drop and maintains a temperature below body temperature for over 600 s. This work presents an effective, fan- and liquid-free thermal management solution with promising applications in small portable electronics and personalized cooling.

The influence of mirror-twin grain boundaries (GBs) on phonon transport in Janus two-dimensional transition-metal dichalcogenides is investigated using neuroevolution-potential (NEP)-based nonequilibrium molecular dynamics (NEMD) simulations. The primary comparison is made among P3m1-type Janus PtSSe and ZrSSe, authentic P3m1 WSSe, and an idealized planar WSSe reference constructed to preserve WS2-like interfacial registry. The P3m1 GBs show strong thermal-transport suppression, whereas the planar WSSe reference retains much higher phonon transmission. Structural, bonding, local projected VDOS, and spectral heat-current analyses indicate that the strong suppression in the P3m1 systems is associated with out-of-plane registry mismatch and enhanced low-frequency interfacial vibrational perturbation. The results are framed as a controlled theoretical study of symmetry-related interfacial phonon scattering in idealized Janus mirror-twin boundary models, with implications for nanoscale thermal management.

Electron-phonon coupling (EPC) and anisotropic thermal transport properties in a series of layered quaternary hydrides XYZH (X = Ba, Sr; Y = Al, Ga; Z = Si, Ge) are systematically investigated via first-principles calculations. These compounds form covalent H-Y-Z layers separated by weakly bonded X atoms. Despite pronounced structural anisotropy, charge transport exhibits unexpectedly weak directional dependence. In contrast, the lattice thermal conductivity exhibits relatively weak anisotropy, with high-frequency hydrogen-dominated optical phonons making unexpectedly substantial contributions to cross-plane heat conduction. EPC strength is found to be highly sensitive to carrier type and composition, being strongest for p-type carriers in AlSi-based systems due to the high electronic density of states near the valence band maximum. Notably, p-type doping induces markedly stronger EPC than n-type doping, leading to a greater reduction in lattice thermal conductivity. This study unveils the unique vibrational and electron-phonon coupling mechanisms in these layered hydrides, providing critical insights for their potential applications in thermal management.

Lattice plainification provides an effective approach to enhance carrier transport and suppress bipolar conduction in Bi2Te3-based thermoelectrics. However, their narrow bandgap often triggers intrinsic carrier excitation at elevated temperatures, limiting energy conversion efficiency. In this work, Pb-doped p-type Bi0.5Sb1.5Te3 (PbxBST, x = 0-0.01) alloys are synthesized to exemplify the lattice plainification strategy, wherein Pb atoms occupy intrinsic Bi vacancies and homogenize the lattice. This targeted modification not only enhances carrier concentration and electrical conductivity but also reduces bipolar thermal conductivity by minimizing structural disorder. As a result, the optimized Pb0.009BST sample achieves a peak ZT of 1.38 at 400 K, similar to 75 K higher than the pristine sample, and an average ZT of 1.24 over 300-500 K-nearly twice that of undoped Bi0.5Sb1.5Te3. Furthermore, a flexible thermoelectric device assembled from Pb0.009BST and commercial n-type Bi2Te2.7Se0.3 exhibits noted performance, delivering a power density of 8.7 mW cm(-2) at Delta T = 50 K and a maximum cooling temperature difference of 60 K. These findings confirm that Pb doping effectively suppresses bipolar thermal excitation and broadens the peak-temperature window. This work offers a practical route toward high-efficiency, flexible BiSbTe-based thermoelectric devices for wearable energy applications.

Cu/Ag-based halides exhibit excellent thermoelectric performance due to strong symmetry-driven phonon anharmonicity, yet theoretical thermal conductivity underestimation remains challenging. Here, to explore the physical mechanisms underlying thermal transport in Cu/Ag-based halides, we investigate the phononic and electronic structures of AX (A = Cu, Ag; X = Br, Cl) zinc-blende compounds using first-principles calculations. We demonstrate that in these four compounds, stronger s-d coupling leads to greater phonon anharmonicity and, consequently, lower thermal conductivity. This strong anharmonicity is the underlying reason for the difficulty in accurately predicting thermal conductivity in AX compounds. By applying pressure, the s-d coupling has a minor change while s-p coupling strengthens, resulting in increased anharmonicity and a negative effect on the pressure-dependent thermal conductivity, except for CuBr. Due to its weaker intrinsic s-d coupling and lower anharmonicity, CuBr exhibits a positive effect. Our work provides a fundamental understanding of the discrepancies in thermal conductivity calculations and offers comprehensive theoretical guidance for the design and application of thermoelectric devices.

Thermal concealment is vital for minimizing the visibility of individuals and vehicles to contemporary infrared surveillance technologies. Traditional approaches, such as emissivity modulation, are effective only in scenarios where the ambient temperature is lower than that of the target and typically exhibit response times on the order of minutes. Other temperature regulation methods generally operate within a restricted temperature range. This work presents an active thermal concealment cloak based on thermoelectric devices, integrating functionalities of infrared camouflage, deception, and information display. By optimizing the circuit design and incorporating a low-reflectivity black porous Ethylene-Vinyl Acetate film, the cloak achieves a uniform temperature distribution, eliminating distinct cold or hot boundaries, and exhibits strong resistance to light interference. Enhanced by bottom-side heat dissipation, the device functions effectively across a wide temperature range from 5.77 °C to 109.16 °C and responds rapidly in just 2.03 seconds. Through the self-developed application, each panel pixel on the device can be independently temperature-controlled, allowing for pre-programmed alterations in the shape and color of the concealed target to enable infrared deception. Additionally, a kirigami structure is employed to enhance the device’s bendability, facilitating the implementation of curved camouflage and wearable IR information transmission.

Recently, the Anderson disorder-induced topological Anderson amorphous insulator has been proposed in a two-dimensional amorphous lattice. However, the interplay between Anderson disorder and amorphous higher-order band topology remains unclear. In this work, we investigate the effects of Anderson disorder on the higher-order topological amorphous phase. We demonstrate that the higher-order topological amorphous phase exhibits robustness against weak disorder but is destroyed by strong disorder. In addition, the Anderson disorder-induced phase transition from a topologically trivial amorphous insulator phase to a higher-order topological amorphous insulator phase, dubbed the higher-order topological Anderson amorphous insulator, is characterized by a quantized quadrupole moment and the existence of topological corner states. Our findings may greatly enrich the study of the interplay between disorder and higher-order topology in amorphous systems and add a new dimension to the topological states of matter.

Pyroelectric sensors based on pyroelectric effect have a wide range of applications. However, the use of lead-containing materials limits their development. In this paper, Na0.5Bi0.5TiO3-Na0.5Bi4.5TiO15-Mn lead-free pyroelectric ceramics are used as sensitive materials to prepare pyroelectric sensors. Na0.5Bi0.5TiO3-Na0.5Bi4.5TiO15-Mn ceramics can achieve 7.58 × 10–4 C·m−2·K−1 high-room-temperature pyroelectric coefficient and depolarization temperature of 151 °C. Due to the low dielectric constant and loss caused by Mn doping, the high detection rate value of 24.382 μPa−1/2 is obtained. The voltage response rate and specific detection rate of the sensor prepared on this basis can attain the JC-T 2397-2017 (εr > 200, tanδ < 5

Lattice thermal conductivity (LTC) is a critical parameter for thermal transport properties, playing a pivotal role in advancing thermoelectric materials and thermal management technologies. Traditional computational methods, such as Density Functional Theory (DFT) and Molecular Dynamics (MD), are resource-intensive, limiting their applicability for high-throughput LTC prediction. While AI-driven approaches have made significant strides in material science, the trade-off between accuracy and interpretability remains a major bottleneck. In this study, we introduce an interpretable deep learning framework that enables rapid and accurate LTC prediction, effectively bridging the gap between interpretability and precision. Leveraging this framework, we identify and validate four promising thermal conductors/insulators using DFT and MD. Moreover, by combining sensitivity analysis with DFT calculations, we uncover novel insights into phonon thermal transport mechanisms, providing a deeper understanding of the underlying physics. This work not only accelerates the discovery of thermal materials but also sets a new benchmark for interpretable AI in material science.

In recent years, the interplay between non-Hermiticity and band topology is expected to uncover numerous novel physical phenomena. However, the majority of research has focused on periodic crystalline structures, with comparatively fewer studies exploring quasicrystalline systems. In this paper, we delve into the influence of asymmetric hopping on the topological insulators, specifically focusing on quantum spin Hall insulators and higher-order topological insulators in an octagonal Ammann-Beenker quasicrystalline lattice. We demonstrate that asymmetric hopping can significantly alter the distribution of edge states, leading to a uniform distribution across all boundaries or localizing them at a single edge, depending on the symmetry adjustments. Furthermore, we explore the robustness of higher-order topological corner states under perturbations, showing that these states can maintain their distribution even in the presence of non-Hermiticity. Our findings not only expand the current understanding of topological states in quasicrystals under non-Hermitian conditions, but also provide valuable theoretical guidance for manipulating corner state distributions in non-Hermitian quasicrystalline higher-order topological insulators.

Thermoelectric materials represent an innovative energy solution, capable of converting waste heat into usable electrical power. Recent advances have leveraged machine learning to identify new thermoelectric materials, yet challenges remain in balancing applicability, feature complexity, and interpretability. In this study, we introduce an interpretable framework based on ensemble learning and Magpie chemical element features to predict the power factor (PF) of various materials. Our approach yields approximate analytical expressions for PF using simple elemental features, providing both accuracy and transparency. We validate our predictions with density functional theory, successfully identifying two high-PF selenides as promising candidates for thermoelectric applications.

Based on existing studies, we identified that the heat sinks used in wearable thermoelectric coolers (WTECs) are predominantly bulky, which limits their practicality and comfort. To address this issue, we propose the use of phase-change composite materials (PCCMs) due to their inherent flexibility and thermal properties. Through comprehensive theoretical analysis, numerical simulations, and experimental validation, we successfully optimized the design of a WTEC.

Graph neural networks (GNNs) are designed to extract latent patterns from graph-structured data, making them particularly well suited for crystal representation learning. Here, we propose a GNN model tailored for estimating electronic transport coefficients in inorganic thermoelectric crystals. The model encodes crystal structures and physicochemical properties in a multiscale manner, encompassing global, atomic, bond, and angular levels. It achieves state-of-the-art performance on benchmark datasets with remarkable extrapolative capability. By combining the proposed GNN with ab initio calculations, we successfully identify compounds exhibiting outstanding electronic transport properties and further perform interpretability analyses from both global and atomic perspectives, tracing the origins of their distinct transport behaviors. Interestingly, the decision process of the model naturally reveals underlying physical patterns, offering new insights into computer-assisted materials design.

The thermoelectric performance of materials exhibits complex nonlinear dependencies on both elemental types and their proportions, rendering traditional trial-and-error approaches inefficient and time-consuming for material discovery. In this work, we present a deep learning model capable of accurately predicting thermoelectric properties of doped materials directly from their chemical formulas, achieving state-of-the-art performance. To enhance interpretability, we further incorporate sensitivity analysis techniques to elucidate how physical descriptors affect the thermoelectric figure of merit (zT). Moreover, we establish a coupled framework that integrates a surrogate model with a multi-objective genetic algorithm to efficiently explore the vast compositional space for high-performance candidates. Experimental validation confirms the discovery of a novel thermoelectric material with superior $zT$ values in the medium-temperature regime.

The rapid advancement of flexible electronics and wearable sensors has heightened demands for stretchable structures that excel in conformability, dynamic motion adaptability, stability under cyclic stretches, and antidistortion properties, holding significant commercial value. Traditional stretchable designs have often compromised the fill factor to achieve in-plane stretchability by incorporating electrodes with stretchable or prestrained architectures. In this article, we introduce a novel bidirectional spiral-hinge kirigami mechanical metamaterial (BSHK-MM) design with a remarkable fill factor of 77.3%. This design significantly enhances stretchability in both in-plane (80%) and out-of-plane (12496%) directions, providing exceptional conformability, dynamic motion adaptability, and resistance to distortion. The stress-strain curve of the BSHK-MM structure was analyzed through mechanical simulation, proving the potential for further manipulation. To demonstrate the potential of this design, we fabricated a 5 × 5 inorganic light-emitting diode (LED) display based on this concept. This device functions effectively under 80% in-plane stretching and can endure 10000 cyclic stretches while returning to its original state with negligible resistance variation. Furthermore, it demonstrates exceptional resistance to distortion under both in-plane and substantial out-of-plane stretching. This LED display exemplifies the broad applicability of our BSHK-MM design concept to various types of stretchable electronics, highlighting its vast potential across a wide range of applications.