Nature Reviews Materials最新文献

Defect tolerance is a concept applied in photovoltaics to explain semiconductors such as lead-halide perovskites that excel without relying on single-crystalline growth. It differentiates from the mere absence of defects, emphasizing on minimizing the influence of defects on minority carrier lifetimes. Whether defect tolerance is the only reason for the superiority of lead-halide-perovskite-based solution-processed solar cells is still controversial. However, the defect tolerance of various semiconductor structures and materials has been experimentally suggested and, in some cases, proven. In this Perspective, we explore defect tolerance across material science, defect characterization and computational modelling. With a primary focus on electrically or optically active defects, we systematically compare computational and experimental results from the literature. We aim to address the complexity arising from diverse theoretical approaches that have yielded partially contradictory results. Additionally, experimental findings have been subject to varied interpretations, ranging from defect signals to ion migration. We endeavour to chart a course through this intricacy and seek to establish a rigorous framework for the identification and quantitative assessment of defect tolerance.

Correction to: Nature Reviews Materials https://doi.org/10.1038/s41578-024-00731-9, published online 18 October 2024.

Metal-halide perovskite solar cells have achieved power conversion efficiencies comparable to those of silicon photovoltaic (PV) devices, approaching 27% for single-junction devices. The durability of the devices, however, lags far behind their performance. Their practical implementation implies the subjection of the material and devices to temperature cycles of varying intensity, driven by diurnal cycles or geographical characteristics. Thus, it is vital to develop devices that are resilient to temperature cycling. This Perspective analyses the behaviour of perovskite devices under temperature cycling. We discuss the crystallographic structural evolution of the perovskite layer, reactions and/or interactions among stacked layers, PV properties and photocatalysed thermal reactions. We highlight effective strategies for improving stability under temperature cycling, such as enhancing material crystallinity or relieving interlayer thermal stress using buffer layers. Additionally, we outline existing standards and protocols for temperature cycling testing and we propose a unified approach that could facilitate valuable cross-study comparisons among scientific and industrial research laboratories. Finally, we share our outlook on strategies to develop perovskite PV devices with exceptional real-world operating stability.

Altermagnets are characterized by non-relativistic alternating spin splitting in the band structure and collinear compensated magnetic moments in real space. They combine the advantages of ferromagnetic and antiferromagnetic order, exhibiting time-reversal symmetry-breaking magneto responses, vanishing stray fields and high-frequency spin dynamics. Consequently, altermagnets hold great potential for various research fields, especially for developing spintronic devices such as high-density magnetic memories and terahertz nano-oscillators. Furthermore, altermagnetism is found in a broad spectrum of materials, including metals, semiconductors, insulators and superconductors, thereby stimulating widespread interest in functional material research. In this Perspective, we provide an overview of recent experimental progress in altermagnets, focusing particularly on observations of lifted spin degeneracy via spectroscopic techniques and the resultant spin transport phenomena. Additionally, we discuss future research directions in altermagnets, encompassing fields such as spintronics, magnonics, ultrafast photonics and phononics, and properties such as superconductivity, topology and multiferroicity.

Rapid developments in electric vehicles and portable electronic devices have fuelled demand for high-energy batteries. Along these lines, chalcogen-driven static conversion batteries (CSCBs), which operate by multielectron transfer, are attracting attention from academia and industry. Because of their high capacity and high voltage output, CSCBs are promising for efficient energy-storage applications. This Review surveys efforts to implement chalcogens with multivalent conversion as the high-energy redox-active component in various rechargeable batteries. First, we examine the evolution of CSCBs and summarize the merits and limitations of these batteries. Subsequently, we discuss state-of-the-art redox mechanisms, approaches for multivalent conversion activation, problems faced in using CSCBs and strategies for enhancing their performance. We also describe the potential of using chalcogens with multivalent conversion chemistry for halogen fixation in reversible multistage processes. Finally, we cover the challenges associated with the design of high-performance CSCBs and provide guidelines for their future design.

Optical microscopy has a key role in research, development and quality control across a wide range of scientific, technological and medical fields. However, diffraction limits the spatial resolution of conventional optical instruments to about half the illumination wavelength. A technique that surpasses the diffraction limit in the wide spectral range between visible and terahertz frequencies is scattering-type scanning near-field optical microscopy (s-SNOM). The basis of s-SNOM is an atomic force microscope in which the tip is illuminated with light from the visible to the terahertz spectral range. By recording the elastically tip-scattered light while scanning the sample below the tip, s-SNOM yields near-field optical images with a remarkable resolution of 10 nm, simultaneously with the standard atomic force microscopic topography image. This resolution is independent of the illumination wavelength, rendering s-SNOM a versatile nanoimaging and nanospectroscopy technique for fundamental and applied studies of materials, structures and phenomena. This Review presents an overview of the fundamental principles governing the measurement and interpretation of near-field contrasts and discusses key applications of s-SNOM. We also showcase emerging developments that enable s-SNOM to operate under various environmental conditions, including cryogenic temperatures, electric and magnetic fields, electrical currents, strain and liquid environments. All these recent developments broaden the applicability of s-SNOMs for exploring fundamental solid-state and quantum phenomena, biological matter, catalytic reactions and more.