Lower-cost thermoelectrics: Thermoelectric materials convert heat to electricity, making them attractive for heat harvesting or cooling applications. However, many high-performance thermoelectrics are made of expensive or toxic materials. He et al. found that a material composed of primarily tin and sulfur could be optimized to have relatively good thermoelectric properties. Introducing about 10% selenium to tin sulfide helped tune these properties by electronic band manipulation. This material is a step toward more earth-abundant, less toxic, and lower-cost thermoelectrics than the telluride-based materials currently in use. Science , this issue p. 1418

The piezoelectric properties of lead zirconate titanate [Pb(Zr,Ti)O ₃ or PZT] ceramics could be enhanced by fabricating textured ceramics that would align the crystal grains along specific orientations. We present a seed-passivated texturing process to fabricate textured PZT ceramics by using newly developed Ba(Zr,Ti)O ₃ microplatelet templates. This process not only ensures the template-induced grain growth in titanium-rich PZT layers but also facilitates desired composition through interlayer diffusion of zirconium and titanium. We successfully prepared textured PZT ceramics with outstanding properties, including Curie temperatures of 360°C, piezoelectric coefficients d ₃₃ of 760 picocoulombs per newton and g ₃₃ of 100 millivolt meters per newton, and electromechanical couplings k ₃₃ of 0.85. This study addresses the challenge of fabricating textured rhombohedral PZT ceramics by suppressing the otherwise severe chemical reaction between PZT powder and titanate templates.

Aberration-corrected scanning transmission electron microscopy (AC-STEM) has evolved into the most powerful characterization and manufacturing platform for all materials, especially functional materials with complex structural characteristics that respond dynamically to external fields. It has become possible to directly observe and tune all kinds of defects, including those at the crucial atomic scale. In-depth understanding and technically tailoring structural defects will be of great significance for revealing the structure-performance relation of existing high-property materials, as well as for foreseeing paths to the design of high-performance materials. Insights would be gained from piezoelectrics and thermoelectrics, two representative functional materials. A general strategy is highlighted for optimizing these functional materials’ properties, namely defect engineering at the atomic scale.

Perovskite oxides such as CaMnO ₃ represent promising, eco-friendly thermoelectric alternatives to toxic chalcogenides, yet their performance remains constrained by the inherent resistivity–Seebeck trade-off and high lattice thermal conductivity ([ ] from strong Mn–O bonding. This study pioneers a sintering-driven microstructure engineering strategy to decouple electron–phonon transport in CaMnO ₃ . By optimizing sintering parameters (temperature: 1473–1548[ ]K; duration: 2–10[ ]h), we achieve grain coarsening (1.34→2.46 [ ]m) and porosity reduction, breaking the conventional performance limits. The engineered microstructure exhibits remarkable carrier-weighted mobility ([ ]) of 13.96[ ]cm[ ] and low [ ] at 973[ ]K, synergistically boosting the power factor by 127% (2.227 [ ]) and attaining a peak zT of 0.13 — the highest reported value for pristine CaMnO ₃ thermoelectrics to date. Crucially, we identify 1548[ ]K/4 h as the kinetic threshold for balanced grain growth and densification, stabilizing microstructures (<5% property variation) for industrial scalability. This work establishes a universal sintering–structure–property paradigm to advance perovskite thermoelectrics toward sustainable energy applications.

Large-size electronic-grade polycrystalline silicon is an important material in the semiconductor industry with broad application prospects. However, electronic-grade polycrystalline silicon has extremely high requirements for production technology and currently faces challenges such as carbon impurity breakdown, microstructure and composition nonuniformity and a lack of methods for preparing large-size mirror-like polycrystalline silicon samples. This paper innovatively uses physical methods such as wire cutting, mechanical grinding and ion thinning polishing to prepare large-size polycrystalline silicon samples that are clean, smooth, free from wear and have clear crystal defects. The material was characterized at both macroscopic and microscopic levels using metallographic microscopy, scanning electron microscopy (SEM) with backscattered electron diffraction (EBSD) techniques and scanning transmission electron microscopy (STEM). The crystal structure changes from single crystal silicon core to the surface of the bulk in the large-size polycrystalline silicon samples were revealed, providing a technical basis for optimizing and improving production processes.