编译|冯维维

Nature, 3 April 2025, Volume 640 Issue 8057

《自然》，2025年4月3日，第640卷，8057期

物理学Physics

Downscaling micro- and nano-perovskite LEDs

中国科学家研发世界最小尺寸LED

▲ 作者：Yaxiao Lian, Yaxin Wang, Yucai Yuan, Zhixiang Ren, Weidong Tang, Zhe Liu, Shiyu Xing, Kangyu Ji, Bo Yuan, Yichen Yang, Yuxiang Gao, Shiang Zhang, Ke Zhou, Gan Zhang, Samuel D. Stranks, Baodan Zhao & Dawei Di

▲ 链接：https://www.nature.com/articles/s41586-025-08685-w

▲ 摘要：电子学和光子学的许多技术突破都是通过缩小尺寸——使基本设备尺寸更小的过程——实现的。基于Ⅲ-V半导体的发光二极管（LED）的小型化导致了微型LED，这是显示器的“终极技术”。然而，微型LED的生产成本很高，当像素尺寸减小到10μm或更小时，它们会表现出严重的效率损失，限制了它们在商业应用中的潜力。

研究者展示了一种基于钙钛矿半导体的新型LED的缩小尺寸的模型，使其低于传统的尺寸限制。通过局部接触制造方案，可以防止像素边界的非辐射损失，展示了具有数百微米至约90纳米特征像素长度的微米和纳米钙钛矿LED 。对于近红外（NIR）和绿色微型PeLED，在宽像素长度范围内，平均外部量子效率（EQEs）保持在20%左右，在缩小尺寸时表现出最小的性能降低。

该纳米PeLED的特征像素长度低至约90纳米，是目前报道的最小的LED，在所有类别的LED阵列中实现了127000像素/英寸（PPI）的创纪录高像素密度。他们的演示展示了微型和纳米PeLED作为下一代光源技术的优势，具有前所未有的紧凑性和可扩展性。

▲ Abstract：Many technological breakthroughs in electronics and photonics were made possible by downscaling—the process of making elementary devices smaller in size. The downsizing of light-emitting diodes (LEDs) based on Ⅲ–V semiconductors led to micro-LEDs, an ‘ultimate technology’ for displays. However, micro-LEDs are costly to produce and they exhibit severe efficiency losses when the pixel sizes are reduced to about 10 μm or less, hindering their potential in commercial applications. Here we show the downscaling of an emerging class of LEDs based on perovskite semiconductors to below the conventional size limits. Micro- and nano-perovskite LEDs (micro-PeLEDs/nano-PeLEDs) with characteristic pixel lengths from hundreds of micrometres down to about 90 nm are demonstrated, through a localized contact fabrication scheme that prevents non-radiative losses at the pixel boundaries. For our near-infrared (NIR) and green micro-PeLEDs, average external quantum efficiencies (EQEs) are maintained at around 20% across a wide range of pixel lengths (650 to 3.5 μm), exhibiting minimum performance reduction on downsizing. Our nano-PeLEDs with characteristic pixel lengths down to about 90 nm represent the smallest LEDs reported, enabling a record-high pixel density of 127,000 pixels per inch (PPI) among all classes of LED arrays. Our demonstration showcases the strength of micro- and nano-PeLEDs as a next-generation light-source technology with unprecedented compactness and scalability.

Microsatellite-based real-time quantum key distribution

基于微卫星的实时量子密钥分发

▲ 作者：Yang Li, Wen-Qi Cai, Ji-Gang Ren, Chao-Ze Wang, Meng Yang, Liang Zhang, Hui-Ying Wu, Liang Chang, Jin-Cai Wu, Biao Jin, Hua-Jian Xue, Xue-Jiao Li, Hui Liu, Guang-Wen Yu, Xue-Ying Tao, Ting Chen, Chong-Fei Liu, Wen-Bin Luo, Jie Zhou, Hai-Lin Yong, Yu-Huai Li, Feng-Zhi Li, Cong Jiang, Hao-Ze Chen, Jian-Wei Pan

▲ 链接：https://www.nature.com/articles/s41586-025-08739-z

▲摘要：量子网络提供了一种基础设施，将具有革命性计算、传感和通信能力的量子设备连接起来。量子卫星星座为促进全球范围内的量子网络提供了一种解决方案。墨子号卫星验证了卫星量子通信的可行性；然而，扩大量子卫星群是具有挑战性的，需要小型轻型卫星、便携式地面站和实时安全密钥交换。

研究者解决了这些挑战，并报告了一种能够使用便携式地面站执行空间到地面量子密钥分发的量子微卫星的开发。微型卫星有效载荷重约23公斤，便携式地面站重约100公斤，分别减少1个数量级和2个数量级以上。使用这种设置，他们演示了基于卫星的量子密钥分配与多个地面站，并在单次卫星通过期间实现了多达107万比特的安全密钥共享。

此外，他们将卫星—地面双向光通信与量子通信进行多路复用，实现实时密钥蒸馏和安全通信。他们还在中国和南非这两个在地球上相隔12900多公里的地方建立了一个密钥，可以对图像进行一次性pad加密。紧凑的量子有效载荷可以很容易地组装在现有的空间站或小卫星上，为基于卫星星座的量子和经典网络的广泛实际应用铺平了道路。

▲ Abstract：A quantum network provides an infrastructure that connects quantum devices with revolutionary computing, sensing and communication capabilities. A quantum satellite constellation offers a solution to facilitate the quantum network on a global scale. The Micius satellite has verified the feasibility of satellite quantum communications; however, scaling up quantum satellite constellations is challenging, requiring small lightweight satellites, portable ground stations and real-time secure key exchange. Here we tackle these challenges and report the development of a quantum microsatellite capable of performing space-to-ground quantum key distribution using portable ground stations. The microsatellite payload weighs approximately 23 kilograms, and the portable ground station weighs about 100 kilograms, representing reductions by more than 1 and 2 orders of magnitude, respectively. Using this set-up, we demonstrate satellite-based quantum key distribution with multiple ground stations and achieve the sharing of up to 1.07 million bits of secure keys during a single satellite pass. In addition, we multiplex bidirectional satellite–ground optical communication with quantum communication, enabling key distillation and secure communication in real time. Also, a secret key, enabling one-time pad encryption of images, is created between China and South Africa at locations separated by over 12,900 kilometres on Earth. The compact quantum payload can be readily assembled on existing space stations or small satellites, paving the way for a satellite-constellation-based quantum and classical network for widespread real-life applications.

Water structure and electric fields at the interface of oil droplets

油滴界面处的水结构和电场

▲ 作者：Lixue Shi, R. Allen LaCour, Naixin Qian, Joseph P. Heindel, Xiaoqi Lang, Ruoqi Zhao, Teresa Head-Gordon & Wei Min

▲ 链接：https://www.nature.com/articles/s41586-025-08702-y

▲摘要：界面水表现出丰富而复杂的行为，在化学、生物、地质和工程等领域发挥着重要作用。然而，关于疏水界面上的水的基本性质，如取向顺序、水合氢离子和氢氧根的浓度、不适当的氢键和大电场的存在，仍然存在很多争论。即使使用最先进的实验技术和理论方法，这种争议也源于测量界面系统的挑战。

研究者报告了一种溶液中，界面选择性拉曼光谱方法，使用多元曲线分辨率来探测水中十六烷乳液，并借助于拉曼光谱的单体场理论模型。研究结果表明，与平面油水界面相比，油水乳液界面可以表现出降低的四面体顺序和较弱的氢键，以及大量的自由羟基，在其拉伸模式下经历约95cm^-1的红移。

考虑到已知的油滴静电zeta电位特性，他们提出了从油相发出的强电场（约50~90MVcm^-1）的存在。这个场是间接推断出来的，但有控制实验和理论估计的支持。在由小溶质形成的分子疏水界面或平面油水界面中，这些观察结果要么不存在，要么相反。相反，水结构紊乱和增强的电场是油水乳液中尺度界面的独特特征，可能有助于在疏水—水界面上观察到的加速化学反应性。

▲ Abstract：Interfacial water exhibits rich and complex behaviour, playing an important part in chemistry, biology, geology and engineering. However, there is still much debate on the fundamental properties of water at hydrophobic interfaces, such as orientational ordering, the concentration of hydronium and hydroxide, improper hydrogen bonds and the presence of large electric fields. This controversy arises from the challenges in measuring interfacial systems, even with the most advanced experimental techniques and theoretical approaches available. Here we report on an in-solution, interface-selective Raman spectroscopy method using multivariate curve resolution to probe hexadecane-in-water emulsions, aided by a monomer-field theoretical model for Raman spectroscopy. Our results indicate that oil–water emulsion interfaces can exhibit reduced tetrahedral order and weaker hydrogen bonding, along with a substantial population of free hydroxyl groups that experience about 95 cm^-1 redshift in their stretching mode compared with planar oil–water interfaces. Given the known electrostatic zeta potential characteristic of oil droplets, we propose the existence of a strong electric field (about 50–90MVcm^-1) emanating from the oil phase. This field is inferred indirectly but supported by control experiments and theoretical estimates. These observations are either absent or opposite in the molecular hydrophobic interface formed by small solutes or at planar oil–water interfaces. Instead, water structural disorder and enhanced electric fields emerge as unique features of the mesoscale interface in oil–water emulsions, potentially contributing to the accelerated chemical reactivity observed at hydrophobic–water interfaces.

Solidification of Earth’s mantle led inevitably to a basal magma ocean

地幔凝固导致基底岩浆海洋的形成

▲ 作者：Charles-édouard Boukaré, James Badro & Henri Samuel

▲ 链接：https://www.nature.com/articles/s41586-025-08701-z

▲摘要：对地幔深层地球物理结构的一种主要解释是，它们源于地核上方地球原始基底岩浆海洋自上而下的凝固。然而，固体是首先形成于地幔底部，向上凝固，还是在熔体上方，向下凝固，仍然存在争议。

研究者证明了致密的、富铁的熔体与较轻的、贫铁的固体的引力分离驱动了地幔的演化，而不管熔体曲线和地热在哪里相交。这一过程导致富含氧化铁的熔体在地核上方积聚，形成一个基底岩浆海。

他们采用一种新的多相流体动力学方法，将熔融相关系与地球化学模型相结合，对地幔凝固过程进行了数值模拟。这可以估计原始地球化学储层的组成特征和空间分布，这可能与太古宙岩石中测量到的同位素异常直接相关。

研究者发现大量的固体是在地球表面产生的，而不是在深处，在深部地幔中注入了浅层硅酸盐分异的地球化学特征。这项工作可以为重新研究岩石行星演化的前10亿年中地幔动力学、岩石学和地球化学之间复杂的相互作用奠定基础。

▲ Abstract：One of the main interpretations of deep-rooted geophysical structures in the mantle1 is that they stem from the top-down solidification of the primitive basal magma ocean of Earth above the core. However, it remains debated whether solids first formed at the bottom of the mantle, solidifying upward, or above the melts, solidifying downward. Here we show that gravitational segregation of dense, iron-rich melts from lighter, iron-poor solids drives mantle evolution, regardless of where melting curves and geotherms intersect. This process results in the accumulation of iron-oxide-rich melts above the core, forming a basal magma ocean. We numerically model mantle solidification using a new multiphase fluid dynamics approach that integrates melting phase relations and geochemical models. This enables estimating the compositional signature and spatial distribution of primordial geochemical reservoirs, which may be directly linked to the isotopic anomalies measured in Archean rocks. We find that a substantial amount of solids is produced at the surface of the planet, not at depth, injecting geochemical signatures of shallow silicate fractionation in the deep mantle. This work could serve as a foundation for re-examining the intricate interplay between mantle dynamics, petrology and geochemistry during the first thousand million years of the evolution of rocky planets.

化学Chemistry

Phosphate-enabled mechanochemical PFAS destruction for fluoride reuse

磷酸盐驱动的机械化学PFAS破坏以实现氟化物的再利用

▲ 作者：Long Yang, Zijun Chen, Christopher A. Goult, Thomas Schlatzer, Robert S. Paton & Véronique Gouverneur

▲ 链接：https://www.nature.com/articles/s41586-025-08698-5 

▲ 摘要：全氟烷基和多氟烷基物质（PFASs）是持久性、生物蓄积性和人为污染物，因其对人类健康的不利影响而引起公共和私营部门的关注。虽然已经采用了各种技术来降解全氟辛烷磺酸，重点是非聚合功能化化合物（全氟辛酸和全氟辛烷磺酸），但一种通用的全氟辛烷磺酸破坏方法加上氟回收用于升级循环是非常可取的。

研究者披露了一项将多种PFAS（包括氟塑料聚四氟乙烯和聚偏氟乙烯）转化为高价值氟化学品的协议。为了实现这一目标，PFASs在无溶剂机械化学条件下与磷酸钾盐反应，这是一种矿化过程，可以回收氟作为KF和K₂PO₃F进行氟化化学。磷酸盐可以回收再利用，这意味着对磷循环没有有害影响。因此，全氟化合物不仅是可破坏的，而且现在可以为可持续的循环氟经济作出贡献。

▲ Abstract：Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are persistent, bioaccumulative and anthropogenic pollutants that have attracted the attention of the public and private sectors because of their adverse impact on human health. Although various technologies have been deployed to degrade PFASs with a focus on non-polymeric functionalized compounds (perfluorooctanoic acid and perfluorooctanesulfonic acid), a general PFAS destruction method coupled with fluorine recovery for upcycling is highly desirable.Here we disclose a protocol that converts multiple classes of PFAS, including the fluoroplastics polytetrafluoroethylene and polyvinylidene fluoride, into high-value fluorochemicals. To achieve this, PFASs were reacted with potassium phosphate salts under solvent-free mechanochemical conditions, a mineralization process enabling fluorine recovery as KF and K₂PO₃F for fluorination chemistry. The phosphate salts can be recovered for reuse, implying no detrimental impact on the phosphorus cycle. Therefore, PFASs are not only destructible but can now contribute to a sustainable circular fluorine economy.

Photoinduced copper-catalysed deracemization of alkyl halides

光诱导铜催化烷基卤化物脱羧

▲ 作者：Feng Zhong, Renhe Li, Binh Khanh Mai, Peng Liu & Gregory C. Fu

▲ 链接：https://www.nature.com/articles/s41586-025-08784-8

▲摘要：脱消旋是一种产生对映体富集化合物的新策略，其中容易获得的外消旋起始材料的两个对映体转化为单个对映体，通常通过光诱导催化剂的作用。这种潜在的强大不对称催化方法的原理证明已经被描述；然而，实质性的挑战尚未得到解决。

研究者描述了一种解决这些挑战的简单方法，使用手性铜催化剂，由市售成分原位生成，通过碳—卤素键裂解实现叔（和仲）烷基卤化物的光诱导离中心化。机理研究（包括假设中间体的独立合成，光物理、光谱和反应性研究以及密度泛函理论计算）为他们提出的催化循环中的关键步骤和中间体提供了支持，并深入了解了对映体选择性的起源。

▲ Abstract：Deracemization is an emerging strategy for generating enantioenriched compounds wherein the two enantiomers of a readily available racemic starting material are transformed into a single enantiomer, typically through the action of a light-induced catalyst. Excellent proof of principle for this potentially powerful approach to asymmetric catalysis has been described; nevertheless, substantial challenges have not yet been addressed, including the exploitation of carbon–heteroatom (rather than only carbon–hydrogen and carbon–carbon) bond cleavage to achieve deracemization, as well as the development of processes that provide broad classes of useful enantioenriched compounds and tetrasubstituted stereocentres. Here we describe a straightforward method that addresses these challenges, using a chiral copper catalyst, generated in situ from commercially available components, to achieve the photoinduced deracemization of tertiary (and secondary) alkyl halides through carbon–halogen bond cleavage. Mechanistic studies (including the independent synthesis of postulated intermediates, photophysical, spectroscopic and reactivity studies, and density functional theory calculations) provide support for the key steps and intermediates in our proposed catalytic cycle, as well as insight into the origin of enantioselectivity.