二维堆垛材料的光学响应和电荷转移机理研究及模块化设计策略

The emergent family of two dimensional (2D) materials has demonstrated its incomparable role in modern electronic and optoelectronic applications. Nevertheless, the development of 2D stacking compound, an appealing and inevitable step towards the ideality of functional integration, is still in its infancy, which is currently limited by the lack of rational design strategies for sequence optimization. In this project, we aim to meet the challenge by proposing a new concept of modular programming. Taking advantage of the intrinsic tunability in real and momentum spaces induced by 2D heterostructures beyond the quantum confinement effects, our idea presumably enables the precise control of nanoscale excitation and charge transfer processes. Systematic analyses by joint computational-experimental efforts will be conducted in three perspectives: (1) Explore the generation, confinement, transport, relaxation, and annihilation of electron, exciton, photon and phonon by multi-scale simulations; (2) Analyze the modular interactions including environmental interference, information transfer, particle/energy flow matching etc. (3) Propose applications with demonstration in prototype systems, and discover new materials by computational screening. Via the systematic analyses of inorganic, organic and hybrid compounds, the project will develop models to describe the light absorption, exciton decay, charge separation/recombination and exciton/charge transport within 2D stacking materials, generate theoretical framework to investigate 2D sequence composed of modules, and propose design strategies to achieve synergy effects. In addition, a universal exploitation platform based on throughput screening and machine learning techniques will be constructed to probe the fundamental structure-property relationship and to highly accelerate the material discovery. The design framework of programmable 2D stacking materials will open an opportunity to accomplish both property scalability and hierarchical functionality integration, and eventually to enable the efficient harness of fantastic properties arising in 2D materials for photovoltaic, sensing, display, integrated circuit, catalysis applications.

发展二维堆垛体系是在纳米尺度实现器件内多功能集成愿景最具潜力的路径，相关探索仍处于起步阶段。本项目提出模块化设计理念以实现高度可调的光电性能，核心在于利用二维异质结波函数在坐标和动量空间的双重本征可调性，对激发弛豫和载流子输运进行精准控制。通过理论和实验手段拟对无机、有机、复合系统开展如下研究: (1)探索电子、激子、光子、声子的产⽣、限域、输运、弛豫、湮灭等物理过程；(2)分析环境屏蔽、低损传输、粒子/能流匹配等模块间相互作用；(3)设计潜在应用⽅案，智能发掘新材料。项目预期建立描述二维堆垛材料中光子吸收、激发态弛豫、电荷分离/复合、激子/电荷输运等机制的物理模型，创造以模块为单位的二维序列理论分析基础，提出以实现协同效应为目标的设计策略。拟搭建新型材料设计平台，融合高通量筛选和机器学习技术，实现大规模高速材料挖掘，为光伏、传感、显示、集成电路、催化反应等场景中性能扩展迭代提供新思路。

本项目进展顺利，完成了大部分预定计划。发展低维堆垛体系是在纳米尺度实现器件内多功能集成愿景最具潜力的路径，相关探索仍处于起步阶段。本项目结合理论分析、第一性原理模拟仿真、机器学习、实验手段对无机、有机、复合堆垛系统开展系统性的研究，主要内容包括：探索低维堆垛系统中显性和隐性低维界面上的物理机理并预测光学、电学、力学性质；研究在低维堆垛系统内调控光学响应、激发态弛豫、载流子输运的物理机制，设计能实现性质优化和多功能集成的堆垛系统；搭建基于机器学习和高通量筛选的计算材料设计平台，发掘具有潜力的低维材料。.本项目的科研成果总结为以下几点：1) 建立了无机二维堆垛材料中原子和电荷迁移的微观物理模型，阐明了界面的几何约束、对称性破缺、量子限域效应影响系统动力学稳定性、压电性质、相变性质的物理机制。2) 建立了有机零维堆垛系统中电子输运的微观物理模型，阐明了界面的电子轨道耦合、磁电效应以及界面分布影响系统电学和磁学性质的物理机制。3) 发展了基于机器学习和高通量筛选的计算材料设计平台，实现了部分材料性质的高效且精准的预测。本项目负责人以第一作者或者通讯作者身份发表了SCI收录的9篇论文，包括5篇中科院一区论文，部分论文发表在Advanced Functional Materials, Nano Letters, Nature Communications, Photonics Research, The Journal of Physical Chemistry Letters等本领域重要期刊。.该系列成果为新型复杂低维堆垛系统的物理建模和现象分析打下了良好的基础，也给低维堆垛材料在光伏、传感、集成电路、催化反应等领域的广泛应用和性能优化提供了新的思路。