SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-3888-9
Flexible thermoelectrics (f-TEs) are being developed rapidly due to their unique advantages, such as direct conversion between electricity and thermal energy, compatibility with curved heat sources, and ease of integration. Over the past decade, significant progress has been made in enhancing the overall performance of f-TE materials and devices, particularly in terms of output power, mechanical flexibility, and durability. Recent research efforts are increasingly focused on translating these advancements into practical applications across diverse fields. For example, f-TE-based multimodal sensors are capable of simultaneously detecting temperature, pressure and strain. In biomedicine, f-TE generators are being explored for wound healing, antibacterial therapy, and neural modulation. Furthermore, f-TE devices show promise in personalized thermal management and hybrid energy harvesting systems. This review moves beyond material preparation and device optimization to focus on the expanding multifunctional applications of f-TEs. We provide a broad perspective by comprehensively exploring the latest progress of f-TEs in intelligent sensing, biomedicine, personalized thermal management, and multifunctional hybrid systems. Key challenges are also discussed, including the development of high-performance flexible devices, robust bio-interfaces, ensuring long-term stability, and achieving intelligent integration with data-driven algorithms and multimodal platforms. Finally, we offer insights into future directions for f-TEs, pointing toward next-generation intelligent and bio-integrated flexible electronics.
SCIENCE CHINA Materials•2026•DOI: 10.1007/s40843-025-4017-y
Lattice distortion via entropy engineering can significantly optimize thermoelectric performance by intensifying phonon scattering. However, excessive lattice distortion in high-entropy materials inevitably hinders carrier transport, limiting the wide-temperature average ZT (ZTave). To enhance the wide-temperature thermoelectric performance of low-cost PbS-based compounds, this work introduces moderate lattice distortion by controlling entropy around 1.0R (R is the gas constant) to balance phonon and carrier transport, alleviating restrictions on carrier mobility. Substantial Se and Te alloying in PbS induces rock-salt lattice distortion, effectively impeding phonon propagation, thus suppressing lattice thermal conductivity (κlat) from 2.41 W m−1 K−1 in PbS to 0.66 W m−1 K−1 in PbS0.5Se0.35Te0.15 at 300 K. Additionally, Cu interstitials are introduced into the lattice-distorted PbS0.5Se0.35Te0.15 to further optimize carrier density and weighted carrier mobility (μW), leading to significant improvement in μW/κlat parameter at 300–773 K. Finally, a room-temperature ZT of 0.53 and a maximum ZT of 1.44 are obtained in PbS0.5Se0.35Te0.15-1%Cu sample, contributing to an impressive ZTave of 1.08 at 300–773 K and a maximum power generation efficiency (ηmax) of 7.5%. The results outperform previously reported cost-effective PbS-based compounds and highlight the importance of lattice distortion regulation in enhancing wide-temperature thermoelectric performance.
SCIENCE CHINA Materials•2025•DOI: 10.1007/s40843-025-3286-2
Traditional thermocouples and infrared thermometers, while widely deployed, exhibit fundamental limitations in temperature range, accuracy, and environmental stability. Rare earth-doped fluorescent materials offer a non-contact alternative by exploiting temperature-dependent optical properties such as fluorescence intensity ratio (FIR) and lifetime. This review systematically analyzes the measurement principles, operational ranges, and application domains of fluorescent thermometry materials. Key material systems including Er3+/Yb3+ co-doped fluorides, oxides, and oxyfluorides are evaluated for their performance in biomedical and aerospace contexts. The review identifies selection rules for rare earth dopants and host matrices, with emphasis on FIR thermometry in visible and near-infrared regions. Critical parameters such as absolute sensitivity, relative sensitivity, and temperature resolution are compared across material platforms. The analysis reveals that core-shell structures and multi-ion co-doping strategies significantly enhance thermal sensitivity and photostability. For biomedical applications, the biological windows (1000–1700 nm) enable deep-tissue penetration, while for thermal barrier coatings, thermographic phosphors provide non-destructive turbine blade temperature mapping. The review concludes with recommendations for future development, including the need for standardized calibration protocols and scalable synthesis routes for industrial adoption.