《科學》（20201002出版）一周論文導讀​

編譯｜馮維維

Science, 2 October 2020, Volume 370 Issue 6512

《科學》2020年10月2日，第370卷，6512期

物理化學

Physical chemistry

Vapor-assisted deposition of highly efficient, stable black-phase FAPbI3 perovskite solar cells

高效、穩定的黑相鈣鈦礦太陽能電池

▲ 作者：Haizhou Lu, Yuhang Liu, Ursula Rothlisberger, Lirong Zheng, Anders Hagfeldt, Michael Grätzel, etc.

▲ 連結：

https://science.sciencemag.org/content/370/6512/eabb8985

▲ 摘要

黑色α相甲醯亞胺碘化鉛（FAPbI3）帶隙幾乎是太陽能電池的理想材料，但相對於光失活性的黃色δ相來說，它是不穩定的。

作者發現，在100℃蒸汽暴露於甲基硫氰酸銨後，一層黃色相膜轉變為高結晶的黑色相，在85℃蒸汽暴露500小時後，該結構仍保持不變。用這種材料製作的太陽能電池的功率轉換效率超過23%。

經過500小時的最大功率跟蹤和一段時間的黑暗恢復，原有效率的94%被保留。

▲ Abstract

The bandgap of the black α-phase FAPbI3 is nearly ideal for solar cells, but it is unstable with respect to the photoinactive yellow δ-phase. Lu et al. found that a film of the yellow phase was converted to a highly crystalline black phase by vapor exposure to methylammonium thiocyanate at 100°C, and it retained this structure after 500 hours at 85°C. Solar cells fabricated with this material had a power conversion efficiency of more than 23%. After 500 hours under maximum power tracking and a period of dark recovery, 94% of the original efficiency was retained.

Impact of strain relaxation on performance of α-formamidinium lead iodide perovskite solar cells

應變弛豫對甲脒根碘化鉛鈣鈦礦太陽能電池性能的影響

▲ 作者：Gwisu Kim, Hanul Min, Kyoung Su Lee, Do Yoon Lee, So Me Yoon, Sang Il Seok

▲ 連結：

https://science.sciencemag.org/content/370/6512/108

▲ 摘要

雖然α相甲醯亞胺碘化鉛（FAPbI3）有一個適用於太陽能電池的帶隙，但它必須用附加的陽離子來穩定。這些成分會對帶隙產生不利影響，並產生晶格應變，從而為載流子產生陷阱。

作者發現，用小的等摩爾量的銫和亞甲二銨陽離子取代甲脒根可以降低晶格應變和陷阱密度。

開路電壓的提高使得功率轉換效率達到了24.4%，並且在最大功率點運行條件下400小時後，封裝器件仍然保持了其初始效率的90%。

▲ Abstract

Although the α-phase of formamidinium lead iodide (FAPbI3) has a suitable bandgap for use in solar cells, it must be stabilized with additional cations. These compositions can adversely affect the bandgap and produce lattice strain that creates trap sites for charge carriers. Kim et al. found that substituting small, equimolar amounts of cesium and methylenediammonium cations for formamidinium reduced the lattice strain and trap densities. The enhancement in open-circuit voltage led to a certified power conversion efficiency of 24.4%, and encapsulated devices retained 90% of their initial efficiency after 400 hours of maximal power point operating conditions.

物理學Physics

Giant temperature span in electrocaloric regenerator

電熱蓄熱器的巨大溫差

▲ 作者：A. Torelló, P. Lheritier, T. Usui, Y. Nouchokgwe, M. Gérard, O. Bouton, S. Hirose, E. Defay

▲ 連結：

https://science.sciencemag.org/content/370/6512/125

▲ 摘要

基於熱量材料的冷卻裝置有望成為下一代冷卻器的候選者。目前已提出了幾種不同機理和工作原理的電熱交換器，但卻一直缺失一個能夠證明具有競爭性的溫度跨度的原型。

作者研製了一種基於鉭酸鉛鈧多層電容器的並聯板式有源電致蓄熱器。在使用有限元模型指導優化結構設計並顯著提高保溫性能後，他們測量到其最高溫度跨度為13.0開爾文。

這打破了一個關鍵的障礙，並證實了電熱材料是有前途的候選冷卻應用。

▲ Abstract

Cooling devices based on caloric materials have emerged as promising candidates to become the next generation of coolers. Several electrocaloric (EC) heat exchangers have been proposed that use different mechanisms and working principles. However, a prototype that demonstrates a competitive temperature span has been missing. We developed a parallel-plate active EC regenerator based on lead scandium tantalate multilayer capacitors. After optimizing the structural design by using finite element modeling for guidance and to considerably improve insulation, we measured a maximum temperature span of 13.0 kelvin. This temperature span breaks a crucial barrier and confirms that EC materials are promising candidates for cooling applications.

A high-performance solid-state electrocaloric cooling system

高性能固態電熱冷卻系統

▲ 作者：Yunda Wang, Ziyang Zhang, Tomoyasu Usui, Michael Benedict, Sakyo Hirose, Joseph Lee, Jamie Kalb, David Schwartz

▲ 連結：

https://science.sciencemag.org/content/370/6512/129

▲ 摘要

電熱製冷是一項新興技術，具有廣泛的潛力，或能打破傳統的空調、冰箱製冷以及電子製冷應用。

作者報告了一個可伸縮、高性能的系統架構，並在一個使用PbSc0.5Ta0.5O3 電熱多層陶瓷電容器的設備中演示，該電容器採用了一種製造相容的工藝。

他們得到的系統溫度跨度為5.2℃，最大熱流為135毫瓦每平方釐米。這個測量的熱流比其他電熱冷卻演示高出四倍以上，並且溫度提升是使用陶瓷多層電容器的電熱系統中最高的。

▲ Abstract

Electrocaloric (EC) cooling is an emerging technology that has broad potential to disrupt conventional air conditioning and refrigeration as well as electronics cooling applications. We report a scalable, high-performance system architecture, demonstrated in a device that uses PbSc0.5Ta0.5O3 EC multilayer ceramic capacitors fabricated in a manufacturing-compatible process. We obtained a system temperature span of 5.2°C and a maximum heat flux of 135 milliwatts per square centimeter. This measured heat flux is more than four times higher than other EC cooling demonstrations, and the temperature lift is among the highest for EC systems that use ceramic multilayer capacitors.

化學Chemistry

Multiplicity of dislocation pathways in a refractory multiprincipal element alloy

難熔多主元素合金中位錯路徑的多重性

▲ 作者：Fulin Wang, Glenn H. Balbus, Shuozhi Xu, Yanqing Su, Jungho Shin, Tresa M. Pollock, Daniel S. Gianola

▲ 連結：

https://science.sciencemag.org/content/370/6512/95

▲ 摘要

含有多種元素的合金可能非常強，但通常韌性差。作者發現，鉬鈮鈦多主元素合金的可塑性適應機制不同。

與所謂的「螺旋」位錯不同，變形通過多種途徑適應，包括「邊緣」位錯和晶體滑移面的激活。這些結果為開發新型高強度合金提供了設計範例。

▲ Abstract

Alloys containing multiple elements can be very strong but often suffer from poor ductility. F. Wang et al. found that different mechanisms accommodated plasticity in a molybdenum-niobium-titanium multiprincipal element alloy. Instead of so-called 「screw」 dislocations, deformation is accommodated by multiple pathways that include 「edge」 dislocations and activation of crystallographic slip planes. These results offer a design paradigm for developing new high-strength alloys.

自動化Automation

A universal system for digitization and automatic execution of the chemical synthesis literature

化學合成文獻的數位化和自動執行的通用系統

▲ 作者：S. Hessam M. Mehr, Matthew Craven, Artem I. Leonov, Graham Keenan, Leroy Cronin

▲ 連結：

https://science.sciencemag.org/content/370/6512/101

▲ 摘要

通常，化學家在進行一個已知的反應時，首先會找到發表論文中描述的方法。

作者報告了一種軟體平臺，它使用自然語言處理將有機化學文獻直接翻譯成可編輯的代碼，這些代碼可以在實驗室中編譯，來驅動化合物的自動合成。

合成程序旨在普遍適用於在分批反應中操作的機器人系統。整個過程已被證明可用於合成止痛劑以及常見的氧化和氟化劑。

▲ Abstract

A typical chemist running a known reaction will start by finding the method described in a published paper. Mehr et al. report a software platform that uses natural language processing to translate the organic chemistry literature directly into editable code, which in turn can be compiled to drive automated synthesis of the compound in the laboratory. The synthesis procedure is intended to be universally applicable to robotic systems operating in a batch reaction architecture. The full process is demonstrated for synthesis of an analgesic as well as common oxidizing and fluorinating agents.

生態學Ecology

Integrated terrestrial-freshwater planning doubles conservation of tropical aquatic species

陸地淡水一體化規劃加倍保護熱帶水生物種

▲ 作者：Cecília G. Leal, Gareth D. Lennox, Silvio F. B. Ferraz, Joice Ferreira, Toby A. Gardner, James R. Thomson, Ricardo R. C. Solar, Jansen Zuanon, Jos Barlow

▲ 連結：

https://science.sciencemag.org/content/370/6512/117

▲ 摘要

在設計陸地保護區時，通常是從陸地的角度考慮物種和系統的需要，並假定任何淡水系統也將受益。

作者通過分析來自巴西亞馬遜地區的兩個地點的數據，驗證了這一假設，並發現它遠不準確：陸地系統對淡水系統帶來的好處很少。

然而，作者還發現，將淡水物種的需求納入整個保護區規劃，淡水收益增加了600%，而陸地收益只減少了1%。他們認為，如果要保護這兩個地區，保護區規劃必須考慮到淡水系統。

▲ Abstract

When designing terrestrial reserves, it is common to consider the needs of species and systems from a terrestrial perspective, with an assumption that any freshwater systems will benefit as well. Leal et al. tested this assumption by analyzing data from two locations in the Brazilian Amazon and found that it is far from accurate: Terrestrial systems confer little benefit to freshwater systems. However, the authors also found that integrating the needs of freshwater species into overall reserve planning increased freshwater benefits by 600% while only decreasing terrestrial outcomes by 1%. They argue that reserve planning must take freshwater systems into account if they are to protect across both realms.