Wu Xiaoyan, Wang Rulin, Zou Hao, Song Bowen, Wen Shizheng, Frauenheim Thomas, Yam ChiYung
Shenzhen JL Computational Science and Applied Research Institute, Longhua District, Shenzhen 518110, China.
College of Physics, Qingdao University, Qingdao 266071, China.
J Chem Theory Comput. 2022 Sep 13;18(9):5502-5512. doi: 10.1021/acs.jctc.2c00547. Epub 2022 Aug 25.
Understanding photon-electron conversion on the nanoscale is essential for future innovations in nano-optoelectronics. In this article, based on nonequilibrium Green's function (NEGF) formalism, we develop a quantum-mechanical method for modeling energy conversion in nanoscale optoelectronic devices. The method allows us to study photoinduced charge transport and electroluminescence processes in realistic devices. First, we investigate the electroluminescence properties of a two-level model with two different treatments of inelastic scatterings. We show the regime where self-consistency between electron and photon is important for correct description of the inelastic scatterings. The method is then applied to model single-molecule junctions based on the density-functional tight-binding approach. The predicted emission spectra are found to be in very good agreement with experimental measurements. For nanostructured materials, the method is further applied to study the photoresponse of a two-dimensional graphene/graphite-CN heterojunction photovoltaic device. The simulations demonstrate clearly the impact of atomistic details on the optoelectronic properties of nanodevices. This work provides a practical theoretical framework that can be applied to model and design realistic nanodevices.
理解纳米尺度上的光子 - 电子转换对于纳米光电子学的未来创新至关重要。在本文中，基于非平衡格林函数（NEGF）形式，我们开发了一种用于对纳米尺度光电器件中的能量转换进行建模的量子力学方法。该方法使我们能够研究实际器件中的光致电荷传输和电致发光过程。首先，我们研究了具有两种不同非弹性散射处理方式的二能级模型的电致发光特性。我们展示了电子与光子之间的自洽性对于正确描述非弹性散射很重要的情况。然后该方法被应用于基于密度泛函紧束缚方法对单分子结进行建模。发现预测的发射光谱与实验测量结果非常吻合。对于纳米结构材料，该方法进一步应用于研究二维石墨烯/石墨 - CN 异质结光伏器件的光响应。模拟清楚地表明了原子细节对纳米器件光电特性的影响。这项工作提供了一个可应用于对实际纳米器件进行建模和设计的实用理论框架。
