UNDERPIN: UNDERstanding quantum Properties of Interfaces from first principles

到目前为止，在光伏领域，现有技术的优化和新技术的开发都是通过更好地控制接口的物理来实现的。在任何控制战略的基础上，都需要对所涉及的不同物理现象及其相互依存有深入的了解。为了更好地理解太阳能电池中界面电荷分离和复合的控制机制，我们将通过从头计算来确定界面形态和电子-空穴动力学之间的相互作用。为此，我们将与实验合作伙伴密切合作，重点研究与光伏相关的各种异质界面，包括Cu(Ga，In)Se2/CDS和Cu(Ga，In)Se2/Back接触结，Cu2ZnSnSe4与第二相之间的界面，以及钙钛矿吸收材料与电子/空穴传输层之间的界面。在广义密度泛函理论和含时密度泛函理论的框架下，我们将重点研究与光伏相关的各种异质界面，包括Cu2ZnSnSe4与第二相之间的界面，以及钙钛矿与电子/空穴传输层之间的界面。我们正在开发一种新的局域混合泛函，它源于GW理论，并被设计为通过依赖于局域介电函数的密度估计来解释电子屏蔽。该函数将在已有实验数据的简单界面上进一步测试，然后用于计算太阳能电池器件中现实界面的电子激发。多亏了我们新的混合泛函，我们将对电子-空穴输运、分离和复合有决定性的理解。通过揭示能源转换的限制因素，我们最终将能够就如何克服这些限制提出建议。这个项目是我最近成立的团队雄心勃勃的长期战略的一部分，它将产生有益的结果，加强现有的合作，并促进与欧洲从事光伏工作的实验者的新合作。

In the domain of photovoltaics it is by now clear that the optimization of existing technologies and the development of new ones passes through a better control of the physics of interfaces. At the basis of any control strategy lies the need for a deep understanding of the different physical phenomena involved and their interdependence. This proposal aims at determining by means of ab initio calculations the interplay between interface morphology and electron-hole dynamics, in order to understand better the mechanisms controlling charge separation and recombination at interfaces in solar cells.To this end, in close collaboration with experimental partners, we will focus on a variety of hetero-interfaces relevant for photovoltaics, including Cu(Ga,In)Se2/CdS and Cu(Ga,In)Se2/back contact junctions, interfaces between Cu2ZnSnSe4 and secondary phases, as well as between perovskite absorbers and electron/hole transport layers.In the framework of generalized density functional theory and time-dependent density functional theory, we are developing a new local hybrid functional, derived from GW theory, and designed to account for electronic screening through its dependence on a density estimator of the local dielectric function. This functional will be further tested on simple interfaces, for which experimental data are available, and then used to calculate electronic excitations at realistic interfaces in solar cell devices. Thanks to our new hybrid functional, we will gain decisive understanding on electron-hole transport, separation and recombination. By shedding light on the limiting factors for energy conversion, we will finally be able to bring suggestions on how to overcome these limitations.This project is part of an ambitious long-term strategy in my recently established group and it will have the beneficial consequence to strengthen existing collaborations and promote new ones with experimentalists working on photovoltaics in Europe.