原位探针技术二维钙钛矿裂纹演变与光力电性能的应变调控机制

There are many kinds of the key features in two-dimensional perovskites such as long charge carrier lifetime, strong photoluminescence, and tunable band gaps and so on and they are widely utilized in new kinds of photoelectric devices. Based on key scientific problems “How to introduce the optical field into the theory of Mechatronic reliability to build the theory of Photo-mechatronic reliability, based on the experiment of the relationship between the crack evolution and the photoelectric performance, after constructing the measurement system of multiple fields coupling of optical, mechanical and electrical fields” and “How to introduce the anisotropy of crystal structure into the theory of Piezo-Phototronics to build the anisotropy model of photo power-voltage-strain, based on the analysis of in situ observation of relationship between the crystal orientation and strain and photoelectric performance” we will investigate the mechanism of strain engineering on physical mechanics and cracks diffusion for two dimensional perovskites material and devices, under multiple fields coupling of optical, mechanical and electrical fields. Based on in situ observation on the relationship between the crack diffusion and evolution and photoelectric and the theory of diffusion and defects in semiconductor, we will construct the model of Photo-mechatronic reliability According to theory of Piezo-Phototronics , the anisotropy will be introduce to the piezoelectric constitutive equation to build the coupling model of power-voltage-strain. Finally, the mechanism of strain engineering on the photoelectric performance will be established under multiple fields coupling and the anisotropy theory of Piezo-Phototronics will be developed.

二维钙钛矿载流子寿命较长、发光效率很高、光电性质可调等，在新型光电器件中用途广泛。针对“搭建原位力学测试系统的光/力/电耦合测试装置，如何结合实验得到的裂纹演化规律与光电响应，把光引入力电失效准则，建立描述光力电行为的理论模型。”和“分析原位获得晶体取向及晶格应变与光电性能的关系，如何将晶体各向异性引入到压电本构，建立各向异性光功率-电压-应变的耦合模型。”关键科学问题，拟开展二维钙钛矿材料器件光力电多场耦合下的裂纹演变与光力电性能应变调控机制的研究。结合原位扫描电镜技术获得裂纹演化和光电性能的变化规律，引入缺陷理论和半导体载流子扩散理论，建立光力电失效模型。基于压电光电子学理论，将晶体各向异性引入到压电本构建立耦合模型。分析提炼二维钙钛矿应变调控光电性能物理机制，发展各向异性的压电光子学理论。

本项目利用原位探针技术，对二维材料的生长断裂机制以及光力电耦合作用开展了深入的物理力学研究。发现了力场耦合作用下二维钙钛矿的光电性能显著增强的现象，阐明了二维钙钛矿中的压电光电子效应增强光电性能的物理机制。构建了一个跨尺度的物理模型，从原子尺度阐明应变、肖特基势垒和宏观尺度光电流之间的关联。发现了范德华界面相互作用导致二维纳米片不完全穿透断裂，阐明了压痕黏附、剥离鼓包、不完全穿透断裂和解理撕裂的演变行为的物理机制。利用原位透射液相技术，实时记录二维金属片从三角形纳米板到六边形纳米板，阐明了特定形状的各向异性二维纳米片的生长机理。本项目的研究为二维材料器件在多场耦合及外界复杂使役作用下的工作提供了新的原理和思想，推动了新型二维材料在多场作用下结构演化、力学、光电性能调控的研究，促进了力学、光学、半导体物理、化学等多学科交叉创新研究。到目前为止项目负责人已在Nat. Nanotechnol、Nat. Mater、Chem. Eng. J、Nanoscale、J. Nanoelectron. Optoe发表论文10篇。项目负责人于2021年获得“香江学者”人才计划；2021获得湖南省优秀青年基金资助；2020年获得湖南省创新人才计划；2022年荣获香港学者协会颁发的香江学者奖；2021年获得国家博士后面上项目资助。

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