Nature, 11 April 2024, VOL 628, ISSUE 8007
《自然》2024年4月11日，第628卷，8007期
材料科学Materials Science
Dopant-additive synergism enhances perovskite solar modules
掺杂剂—添加剂协同增强钙钛矿太阳能组件
▲ 作者：Bin Ding, Yong Ding, Jun Peng, Jan Romano-deGea, Lindsey E. K. Frederiksen, Hiroyuki Kanda, et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07228-z
▲ 摘要：
钙钛矿太阳能电池（PSCs）因其独特的光电特性而成为最有前景的光伏技术之一。然而，与实验室规模的PSCs相比，大面积PSCs的效率较低、稳定性差和可重复性低等问题是阻碍其商业化的主要瓶颈。
研究组报道了一种使用氯化甲铵（MACl）为掺杂剂、1,3—双（氰基甲基）氯化咪唑鎓（[Bcmim]Cl）为路易斯碱离子液体添加剂的协同掺杂剂—添加剂组合策略。该策略有效地抑制了钙钛矿前驱体溶液（PPS）的降解，抑制了MACl的聚集，得到了相均匀、稳定、结晶度高、缺陷较少的钙钛矿薄膜。
该方法助力钙钛矿太阳能组件（PSM）的制造，在27.22 cm2的孔径面积上认证效率达到23.30%，最终稳定在22.97%，标志着最高的认证PSM性能。此外，PSM表现出长期的运行稳定性，在室温下一倍太阳光照连续1000小时后仍保持94.66%的初始效率。
研究组广泛分析了[Bcmim]Cl和MACl之间的相互作用，以揭示导致器件性能增强的机制。该方法有望弥合从实验台到屋顶的差距，推进大面积钙钛矿光伏的生产和商业化。
▲ Abstract：
Perovskite solar cells (PSCs) are among the most promising photovoltaic technologies owing to their exceptional optoelectronic properties. However, the lower efficiency, poor stability and reproducibility issues of large-area PSCs compared with laboratory-scale PSCs are notable drawbacks that hinder their commercialization. Here we report a synergistic dopant-additive combination strategy using methylammonium chloride (MACl) as the dopant and a Lewis-basic ionic-liquid additive, 1,3-bis(cyanomethyl)imidazolium chloride ([Bcmim]Cl). This strategy effectively inhibits the degradation of the perovskite precursor solution (PPS), suppresses the aggregation of MACl and results in phase-homogeneous and stable perovskite films with high crystallinity and fewer defects. This approach enabled the fabrication of perovskite solar modules (PSMs) that achieved a certified efficiency of 23.30% and ultimately stabilized at 22.97% over a 27.22-cm2 aperture area, marking the highest certified PSM performance. Furthermore, the PSMs showed long-term operational stability, maintaining 94.66% of the initial efficiency after 1,000 h under continuous one-sun illumination at room temperature. The interaction between [Bcmim]Cl and MACl was extensively studied to unravel the mechanism leading to an enhancement of device properties. Our approach holds substantial promise for bridging the benchtop-to-rooftop gap and advancing the production and commercialization of large-area perovskite photovoltaics.
Triple-junction solar cells with cyanate in ultrawide-bandgap perovskites
超宽带隙钙钛矿中氰酸盐三结太阳能电池
▲ 作者：Shunchang Liu, Yue Lu, Cao Yu, Jia Li, Ran Luo, Renjun Guo, et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07226-1
▲ 摘要：
没有质量损失的钙钛矿带隙调谐使钙钛矿在太阳能吸收剂中独树一帜，为串联太阳能电池提供了颇有前景的途径。然而对于三结串联应用而言，当钙钛矿带隙增加到1.90 eV以上时，最小化电压损失颇具挑战性。
研究组提出了一种此前未知的假卤化物，即氰酸盐（OCN−），其有效离子半径（1.97 Å）与溴化物（1.95 Å）相当，可作为溴化物的替代品。电子显微镜和X射线散射证实了OCN掺入至钙钛矿晶格中。
这促成了显著的晶格畸变，范围从90.5°到96.6°，碘化物—溴化物分布均匀，微应变一致。由于这些效应，OCN基钙钛矿表现出增强的缺陷形成能和显著降低的非辐射复合。
研究组实现了一个倒置钙钛矿（1.93 eV）单结器件，开路电压（VOC）为1.422 V，VOC×FF（填充因子）乘积超过了Shockley-Queisser极限的80%，且在最大功率点跟踪下性能稳定，最终获得了1 cm2孔径面积下效率为27.62%（认证效率为27.10%）的钙钛矿—钙钛矿—硅三结太阳能电池。
▲ Abstract：
Perovskite bandgap tuning without quality loss makes perovskites unique among solar absorbers, offering promising avenues for tandem solar cells. However, minimizing the voltage loss when their bandgap is increased to above 1.90 eV for triple-junction tandem use is challenging. Here we present a previously unknown pseudohalide, cyanate (OCN−), with a comparable effective ionic radius (1.97Å) to bromide (1.95Å) as a bromide substitute. Electron microscopy and X-ray scattering confirm OCN incorporation into the perovskite lattice. This contributes to notable lattice distortion, ranging from 90.5° to 96.6°, a uniform iodide–bromide distribution and consistent microstrain. Owing to these effects, OCN-based perovskite exhibits enhanced defect formation energy and substantially decreased non-radiative recombination. We achieved an inverted perovskite (1.93 eV) single-junction device with an open-circuit voltage (VOC) of 1.422 V, a VOC× FF (fill factor) product exceeding 80% of the Shockley–Queisser limit and stable performance under maximum power point tracking, culminating in a 27.62% efficiency (27.10% certified efficiency) perovskite–perovskite–silicon triple-junction solar cell with 1 cm2 aperture area.
Metal telluride nanosheets by scalable solid lithiation and exfoliation
金属碲化物纳米片的可扩展固相锂化和剥离
▲ 作者：Liangzhu Zhang, Zixuan Yang, Shun Feng, Zhuobin Guo, Qingchao Jia, Huidan Zeng, et al.
▲ 链接：
https://www.nature.com/articles/s41586-024-07209-2
▲ 摘要：
过渡金属碲化物（TMTs）是探索凝聚态物理、化学和材料科学中奇异性质的理想材料。虽然TMT纳米片已通过自上而下的剥离成功制备，但其规模低于克级，并且需要较长的加工时间，限制了其从实验室到市场的有效应用。
研究组报道了快速和可扩展地合成各种MTe2（M = Nb、Mo、W、Ta、Ti）纳米片的方法，即在10分钟内将块体MTe2固相锂化，并在几秒钟内将其水解。以NbTe2为代表，他们生产了超过100克（108克）的NbTe2纳米片，平均厚度为3.2 nm，平均横向尺寸为6.2 μm，且收率高（>80%）。
还观察到一些有趣的量子现象（如量子振荡和巨磁阻效应），这通常仅限于高度结晶的MTe2纳米片。TMT纳米片还可作为锂氧电池的电催化剂和微型超级电容器（MSCs）的电极。此外，该合成方法对制备合金碲化物、硒化物和硫化物纳米片也有效。
该工作为TMT纳米片的通用和可扩展合成开辟了新机遇，以探索新的量子现象、潜在应用和商业化。
▲ Abstract：
Transition metal tellurides (TMTs) have been ideal materials for exploring exotic properties in condensed-matter physics, chemistry and materials science. Although TMT nanosheets have been produced by top-down exfoliation, their scale is below the gram level and requires a long processing time, restricting their effective application from laboratory to market. We report the fast and scalable synthesis of a wide variety of MTe2 (M = Nb, Mo, W, Ta, Ti) nanosheets by the solid lithiation of bulk MTe2 within 10 min and their subsequent hydrolysis within seconds. Using NbTe2 as a representative, we produced more than a hundred grams (108 g) of NbTe2 nanosheets with 3.2 nm mean thickness, 6.2 μm mean lateral size and a high yield (>80%). Several interesting quantum phenomena, such as quantum oscillations and giant magnetoresistance, were observed that are generally restricted to highly crystalline MTe2 nanosheets. The TMT nanosheets also perform well as electrocatalysts for lithium–oxygen batteries and electrodes for microsupercapacitors (MSCs). Moreover, this synthesis method is efficient for preparing alloyed telluride, selenide and sulfide nanosheets. Our work opens new opportunities for the universal and scalable synthesis of TMT nanosheets for exploring new quantum phenomena, potential applications and commercialization.
化学Chemistry
Force-controlled release of small molecules with a rotaxane actuator
利用轮烷致动器实现小分子的力控释放
▲ 作者：Lei Chen, Robert Nixon & Guillaume De Bo
▲ 链接：
https://www.nature.com/articles/s41586-024-07154-0
▲ 摘要：
在医疗或材料领域，小分子的力控释放为药物递送和治疗剂或报告剂的释放提供了巨大前景。在聚合物机械化学中，聚合物被用作拉伸机械敏感分子（机械基团）的致动器。这种技术可通过重排（机械载体中键断裂的直接或间接结果），或通过笼状、超分子或金属配合物的解离，甚至通过“柔性激活”来释放分子货物。
然而，迄今为止所描述的系统在每次拉伸事件中释放分子的多样性和/或数量方面都颇受限。这是由于难以迭代激活剪式机械载体，因为致动聚合物在第一次激活后会解离。物理封装策略可用于递送更大的货物负载，但这些通常受到非特定（即非机械）释放的影响。
研究组展示了轮烷（一种互锁分子，其中一个大环被捕获在带塞的轴上）作为一种有效致动器来触发附加在其轴上的货物分子的释放。在溶液中通过超声处理以及在固块中通过压缩处理，每个轮烷致动器可释放多达5个货物分子，释放效率分别高达71%和30%，这使该轮烷装置成为迄今为止实现的最有效释放系统之一。
研究组还演示了三种代表性功能分子（药物、荧光标签和有机催化剂）的释放，并预计该设备可释放多种货物分子。该轮烷致动器为各种力控释放应用提供了一个通用平台。
▲ Abstract：
Force-controlled release of small molecules offers great promise for the delivery of drugs and the release of healing or reporting agents in a medical or materials context. In polymer mechanochemistry, polymers are used as actuators to stretch mechanosensitive molecules (mechanophores). This technique has enabled the release of molecular cargo by rearrangement, as a direct or indirect consequence of bond scission in a mechanophore, or by dissociation of cage, supramolecular or metal complexes, and even by ‘flex activation’. However, the systems described so far are limited in the diversity and/or quantity of the molecules released per stretching event. This is due to the difficulty in iteratively activating scissile mechanophores, as the actuating polymers will dissociate after the first activation. Physical encapsulation strategies can be used to deliver a larger cargo load, but these are often subject to non-specific (that is, non-mechanical) release. Here we show that a rotaxane (an interlocked molecule in which a macrocycle is trapped on a stoppered axle) acts as an efficient actuator to trigger the release of cargo molecules appended to its axle. The release of up to five cargo molecules per rotaxane actuator was demonstrated in solution, by ultrasonication, and in bulk, by compression, achieving a release efficiency of up to 71% and 30%, respectively, which places this rotaxane device among the most efficient release systems achieved so far. We also demonstrate the release of three representative functional molecules (a drug, a fluorescent tag and an organocatalyst), and we anticipate that a large variety of cargo molecules could be released with this device. This rotaxane actuator provides a versatile platform for various force-controlled release applications.
Couple-close construction of polycyclic rings from diradicals
双自由基偶联-环化策略构建多环化物
▲ 作者：Alice Long, Christian J. Oswood, Christopher B. Kelly, Marian C. Bryan & David W. C. MacMillan
▲ 链接：
https://www.nature.com/articles/s41586-024-07181-x
▲ 摘要：
杂芳烃是生物活性分子中普遍存在的结构骨架，与其芳烃对应物相比，具有良好的物理性质。特别是，半饱和杂芳烃具有吸引人的溶解性和较高的sp3碳分数，可提高结合亲和力和特异性。
然而，由于目前合成方法的限制，这些理想结构仍很少见。事实上，半饱和杂环化合物大多通过非模块化的符合预期合成方法艰难制备而成，这降低了产率，限制了化学多样性，在先导物竞争中不占优势。
研究组描述了一种更直观和模块化的偶联—环化方法来构建由双自由基前驱体组成的半饱和环体系。该平台将金属光氧化还原C(sp2) —C (sp3)交叉偶联与分子内Minisci型自由基环化相结合，将丰富的杂芳基卤化物与简单的双官能团原料融合，以此作为双自由基合成子，快速构建了传统方法极难制备的各种类型螺环、桥接和取代饱和环。
所需原料的广泛可及性实现了未开发化学空间区域的取样。试剂控制自由基生成导致高度区域选择性和立体特异性环化，可用于药物支架的后期功能化，从而取代冗长的从头合成。
▲ Abstract：
Heteroarenes are ubiquitous motifs in bioactive molecules, conferring favourable physical properties when compared to their arene counterparts. In particular, semisaturated heteroarenes possess attractive solubility properties and a higher fraction of sp3 carbons, which can improve binding affinity and specificity. However, these desirable structures remain rare owing to limitations in current synthetic methods. Indeed, semisaturated heterocycles are laboriously prepared by means of non-modular fit-for-purpose syntheses, which decrease throughput, limit chemical diversity and preclude their inclusion in many hit-to-lead campaigns. Herein, we describe a more intuitive and modular couple-close approach to build semisaturated ring systems from dual radical precursors. This platform merges metallaphotoredox C(sp2)–C(sp3) cross-coupling with intramolecular Minisci-type radical cyclization to fuse abundant heteroaryl halides with simple bifunctional feedstocks, which serve as the diradical synthons, to rapidly assemble a variety of spirocyclic, bridged and substituted saturated ring types that would be extremely difficult to make by conventional methods. The broad availability of the requisite feedstock materials allows sampling of regions of underexplored chemical space. Reagent-controlled radical generation leads to a highly regioselective and stereospecific annulation that can be used for the late-stage functionalization of pharmaceutical scaffolds, replacing lengthy de novo syntheses.
地球科学One Earth
A global timekeeping problem postponed by global warming
全球变暖推迟了全球计时问题
▲ 作者：Duncan Carr Agnew
▲ 链接：
https://www.nature.com/articles/s41586-024-07170-0
▲ 摘要：
时间与地球自转的历史联系意味着世界标准时间（UTC）密切遵循地球自转。由于旋转速率不是恒定的，UTC包含不连续性（闰秒），这使其在计算机网络中的使用变得复杂。自1972年以来，所有的UTC不连续点都需要增加一闰秒。
研究组通过卫星重力测量，证明格陵兰岛和南极洲冰层加速融化使地球自传角速度比以前更快降低。从观测到的角速度中去除这种影响表明，自1972年以来，地球液态核心的角速度一直在以恒定的速率下降，而地球其他部分的角速度稳步增加。
外推地核和其他相关现象的趋势来预测未来地球定向表明，按照当前定义，到2029年，UTC将需要负一闰秒。这将给计算机网络时间带来前所未有的挑战，并可能需要比计划更早地去更改UTC。如果极地冰层最近没有加速融化，这个问题将会提早3年发生：全球变暖已经影响到全球计时。
▲ Abstract：
The historical association of time with the rotation of Earth has meant that Coordinated Universal Time (UTC) closely follows this rotation. Because the rotation rate is not constant, UTC contains discontinuities (leap seconds), which complicates its use in computer networks. Since 1972, all UTC discontinuities have required that a leap second be added. Here we show that increased melting of ice in Greenland and Antarctica, measured by satellite gravity, has decreased the angular velocity of Earth more rapidly than before. Removing this effect from the observed angular velocity shows that since 1972, the angular velocity of the liquid core of Earth has been decreasing at a constant rate that has steadily increased the angular velocity of the rest of the Earth. Extrapolating the trends for the core and other relevant phenomena to predict future Earth orientation shows that UTC as now defined will require a negative discontinuity by 2029. This will pose an unprecedented problem for computer network timing and may require changes in UTC to be made earlier than is planned. If polar ice melting had not recently accelerated, this problem would occur 3 years earlier: global warming is already affecting global timekeeping.
