卤化物钙钛矿纳米晶体的三阶、高阶非线性光学性能研究及其调制

Halide perovskite nanocrystals have attracted much attention because of their excellent optical and electrical properties compared with traditional semiconductor nanocrystals. Research on the fundamental physics beneath their optical、non-linear optical properties and on the related applications have developed rapidly in recent years. This is of great significance for the development of new high-performance optical and non-linear optical devices and for the development of higher-order non-linear optical diagnosis, imaging and biosensing. On the basis of previous research, this project will combine the experimental study and theoretical simulation to investigate the nonlinear optical properties of perovskite nanocrystals and their further modulation for optimization. First we will prepare a series of halide perovskite nanocrystals and apply external modulation. Secondly we will accurately measure the third-order and higher-order nonlinear optical physical processes in time and frequency domains using multi-photon excitation fluorescence spectroscopy, Z-scan and ultra-fast time-resolved pump-probe/fluorescence spectroscopy. Thirdly, combined with the experimental data, the theories of multi-photon absorption, photoinduced carrier relaxation and electron/energy transfer will be utilized to quantitatively analysis the effects of structural factors such as composition, geometry, band structure and modulation factors such as doping, core-shell structure, component ratio adjustment, silicon oxide/lipid encapsulation, and then establish the underlying physical mechanisms. Fourthly, based on the above experimental measurements and theoretical analysis, a physical model of nonlinear optical processes will be established. Finally, the physical model will be utilized to guide the design/synthesis of materials and the optimization of modulation schemes, in order to significantly improve the nonlinear optical properties of the halide perovskite nanocrystals.

卤化物钙钛矿纳米晶体因其显著优于传统半导体纳米晶体的光电学特性备受人们关注，针对它们的光学、非线性光学基础应用研究在近几年发展迅速，对开发新型高性能光学、非线性光学器件以及发展高阶非线性光学诊疗、成像、生物传感意义重大。本项目将在前期工作基础上，实验和理论相结合深入研究卤化物钙钛矿纳米晶体的非线性光学性质及其调制优化。制备一系列卤化物钙钛矿纳米晶体并对它们进行外加条件调制；结合多光子激发荧光光谱、Z-扫描、超快时间分辨泵浦-探测/荧光光谱精确测量材料在时域和频域上的三阶、高阶非线性光学物理过程；结合实验数据，采用多光子吸收、光激发载流子弛豫、电子/能量转移等理论，定量解析组成成分、几何构型、能带结构等结构因数以及掺杂、核壳结构、组分比例调整、氧化硅/脂质包裹等调制因素的影响规律及物理机制，建立非线性光学物理模型，基于模型指导材料的设计/合成以及调制方案的优化，显著提高材料的非线性光学性能。

卤化物钙钛矿纳米晶体的三阶、高阶非线性光学性质的研究对于开发深层组织非线性光学成像技术和新型高性能非线性光学器件意义重大。本项目深入研究卤化物钙钛矿纳米晶体的三阶、高阶非线性光学性质及其调制优化方法和内在的物理机理，同时对相关应用进行了研究探索。本项目在理论和实验上取得了一些重要成果。本项目系统地总结和分析具有不同晶体结构（从零维到三维结构）的卤化物钙钛矿纳米晶体的非线性光学性质，深入剖析不同内在属性（如结构、组成成分、带隙、尺寸、形状、光谱依赖性等）和外加调制策略（如开发核-壳结构、过渡金属离子掺杂、量子限制在金属有机框架材料的纳米空腔中、与光子晶体形成复合结构、与金属纳米晶体形成复合结构等）对其非线性光学特性的调制规律和物理机理，为调制优化卤化物钙钛矿纳米晶体的非线性光学性质建立了系统完备的理论和技术方案。本项目系统分析卤化物钙钛矿太阳能电池中铅对人类、动物和生态系统的毒性，全面讨论和解析应用从器件外部到内部的器件架构工程减少铅泄漏的策略，并提出几种降低潜在铅泄漏风险的方案，为现实的商业化应用打下了坚实的基础。本项目研究应用卤化物钙钛矿纳米晶体的简并双光子和三光子激发荧光在生物组织模型中进行深层成像，初步实现成像深度1.5 mm；研究应用卤化物钙钛矿纳米晶体的非简并双光子吸收探测光纤通信波段红外光，探测灵敏度接近100 nJ，响应度接近0.5 VW-1，激发光强低于60 GWcm-2；研究应用卤化物钙钛矿纳米晶体的非简并双光子吸收实现近红外光的超快全光调制，调制深度接近70%，调制速率大于100 GHz，调制光强低于1 GWcm-2。项目负责人以第一作者或通讯作者发表中科院大类一区SCI论文2篇，其中影响因子>30论文1篇[Advanced Materials, IF=32.086, (2021)]，影响因子>20论文1篇[ACS Energy Letters, IF=24.052, (2022)]。受疫情和其他科研经费长期无法到位影响，目前有3篇研究论文还在审稿状态，有3项发明专利正在准备申请。获全国学术会议特邀报告3次。培养硕士研究生8名，其中已毕业硕士3名。