Unveiling defect-strain relationships in halide perovskite solar cells through modelling-experiment combinations

最近，欧盟委员会宣布了一系列名为欧洲绿色协议的政策倡议，旨在到2050年实现欧洲温室气体净零排放，预计光伏技术将在可持续能源发电中发挥重要作用。尽管卤化物钙钛矿由于低成本的溶液可加工性和高的功率转换效率而被强调为一类最有前途的太阳能电池材料，但由于钙钛矿薄膜中的缺陷而产生的非辐射损失和化学分解阻碍了它们的成功商业化。这个项目的主要目标是揭示缺陷-应变关系，并提供一种方法来开发作为缺陷控制的额外杠杆。为了实现这一目标，需要了解卤化物钙钛矿晶格位置的微观结构变化如何影响宏观太阳能电池的性能，这不是单一的研究方法可以完成的。因此，一个多学科的方法--各种光谱和显微镜测量作为两个终点之间的垫脚石--是这一雄心勃勃的项目的重要组成部分。申请者郑永光博士将采用最先进的第一原理材料模拟技术，以确定(I)原生点缺陷；(Ii)非本征掺杂；以及(Iii)卤化物钙钛矿太阳能电池中扩展的缺陷到晶格应变的响应，并将得到东道主(Samuel D.Stranks博士和剑桥大学Straks Lab)的尖端实验验证。该项目的成果将为提高器件的效率和稳定性提供实用的解决方案，从而加快卤化物钙钛矿太阳能电池在公开市场上的商业化进程。因此，这项工作将为世界范围内的零碳能源生产运动做出贡献，并最终缓解全球变暖。

Recently, European Commission announced a set of policy initiatives called European Green Deal which aims at net zero greenhouse gases in Europe by 2050, and photovoltaic technologies are expected to play a significant role in sustainable energy generation. Although halide perovskites have been highlighted as a class of the most promising materials for solar cells due to a combination of low-cost solution processibility and high power conversion efficiency, non-radiative losses and chemical decomposition originated from defects in the perovskite films prevent them from being commercialised successfully. The primary goal of this project is to unveil defect-strain relationships and to provide a way to exploit as an extra lever for defect control. To attain the goal, how microscopic structural changes at halide perovskite lattice sites affect performance of macroscopic solar cells needs to be understood, which cannot be done from a single research technique. A multidisciplinary approach - various spectroscopy and microscopy measurements as stepping stones in between the two end points - is, thus, an essential part of this ambitiously proposed project. The applicant (Dr Young-Kwang Jung) will perform state-of-the-art first-principles materials simulation techniques to identify responses of (i) native point defects; (ii) extrinsic dopants; and (iii) extended defects to lattice strain in halide perovskite solar cells, which will be complemented by cutting edge experimental validation from the host (Dr Samuel D. Stranks and the StraksLab at the University of Cambridge). The results of this project will provide practical solutions to improve the device efficiency and stability, which will accelerate commercialisation of halide perovskite solar cells in the public market. Consequently, this work will contribute the world-wide movement for zero-carbon energy generation, and ultimately, will alleviate the global warming.