Addressing Dynamic Donor:Acceptor and Electrode Interfaces in Organic Bulk-Heterojunction and Perovskite Solar Cells Under Device-Operating Condition

主要研究者：胡斌编号：1438181非技术性描述太阳是地球上最丰富的无污染能源。用于将阳光转化为电能的太阳能电池，也称为光伏（PV）太阳能电池，在运行过程中会经历各种复杂的电气过程，从而降低整体太阳能转化效率。 该项目将开发和使用一种基于磁场测量的新技术，以探测两大类光伏器件（基于有机聚合物的光伏（OPV）太阳能电池和基于钙钛矿材料的半导体太阳能光伏电池）中材料界面处的这些电气过程，而这些器件正在实际操作中。 OPV器件提供了希望，因为它们可以由相对便宜的有机聚合物材料制成，钙钛矿材料提供了希望，因为它们是从地球上丰富的矿物质中获得的。具有较高的太阳能转换效率。 对这些PV材料中材料界面处的有用和无用光伏过程的基本理解将建议材料合成途径和设备工程，其可能导致两种PV设备类别中的太阳能转换效率增加。 拟议的活动还将提供跨学科机会，以加强课堂教学，为科学和工程领域代表性不足群体的学生提供研究培训机会，并为高中学生提供关于有机聚合物太阳能电池专题的外联活动。 技术描述在光伏（PV）器件中，当来自太阳光的光子被吸收并转换成电子-空穴对时，存在几种损耗机制，这些损耗机制阻止电荷作为电流从器件带走，从而导致太阳能转换效率降低。本项目的总体目标是通过独特的磁场测量技术，对材料界面处的复合损耗机制有一个基本的了解。 具体而言，该项目将在设备操作条件下使用真实的操作设备，测量磁场诱导的光电流和光诱导电容，以分别探测激子有机聚合物基光伏（OPV）设备和电极界面非激子钙钛矿薄膜光伏设备中的动态供体/受体界面的结合能和电荷转移状态。 拟议的研究将获得关于如何通过控制极化和能量参数来调整激子体异质结OPV器件的供体/受体界面处的电子-空穴结合能的见解，以及如何通过介电效应来增强非激子钙钛矿薄膜PV器件中电极界面处的电荷收集。该研究计划将集中在三个任务上，包括材料加工和器件工程，以调整供体/受体和电极界面处的偏振和能量参数，对供体/受体和电极界面处发生的有用和无用光伏过程的实验研究，以及最后，阐明了控制供体/受体界面处的电子-空穴结合能和电极界面处的电荷收集的关键参数。 对动态供体/受体和电极界面处的有用和无用光伏过程的基本理解将建议材料合成途径和装置工程，其可潜在地导致激子体异质结OPV和非激子钙钛矿薄膜PV装置两者中的太阳能转换效率增加。 在教育和扩大参与方面，拟议的活动还将提供跨学科机会，以加强课堂教学，为科学和工程专业代表性不足群体的学生提供研究培训机会，并为高中学生提供关于有机聚合物太阳能电池专题的外联活动。

Principal Investigator: Bin Hu Number: 1438181Nontechnical DescriptionThe sun represents the most abundant potential source of pollution-free energy on earth. Solar cells for the conversion of sunlight to electricity, also known as photovoltaic (PV) solar cells, suffer from a variety of complicated electrical processes during their operation that lower the overall solar energy conversion efficiency. This project will develop and use a novel technique based on magnetic field measurements to probe these electrical processes at material interfaces within two major classes of photovoltaic devices, organic polymer based photovoltaic (OPV) solar cells, and perovskite material based semiconductor solar PV cells, while these devices are in actual operation. OPV devices offer promise because they can be made from relatively inexpensive organic polymer materials, and perovskite materials offer promise because they are obtained from minerals abundant in the earth?s crust and have relatively high solar energy conversion efficiencies. Fundamental understanding of the useful and non-useful photovoltaic processes at material interfaces within these PV materials will suggest materials synthesis pathways and device engineering that can potentially lead to increased solar energy conversion efficiency in both PV device classes. The proposed activities will also offer interdisciplinary opportunities to enhance class teaching, research training opportunities for students from under-represented groups in science and engineering, and outreach activities for high-school students on the topic of organic polymer based solar cells. Technical DescriptionIn a photovoltaic (PV) device, when a photon from sunlight is absorbed and converted into an electron-hole pair, there are several loss mechanisms which prevent the charge from being carried away from the device as electric current, resulting in lowered solar energy conversion efficiency. The overall goal of this project is to gain a fundamental understanding of these recombination loss mechanisms at material interfaces though a unique magnetic field measurement technique. Specifically, the project will make measurements of magnetic field induced photocurrent and photo-induced capacitance to probe the binding energy and charge transfer states of the dynamic donor/acceptor interface in excitonic organic polymer based photovoltaic (OPV) devices, and the electrode interface non-excitonic perovskite thin-film photovoltaic devices respectively, using real operating devices under device operating conditions. The proposed research will gain insights on how to tune the electron-hole binding energies at the donor/acceptor interface for excitonic, bulk hetero-junction OPV devices through control of polarization and energy parameters, and on how to enhance the charge collection at the electrode interface in non-excitonic perovskite thin-film PV devices through dielectric effects. The research plan will focus on three tasks, including materials processing and device engineering to tune polarization and energy parameters at donor/acceptor and electrode interfaces, experimental studies on the useful and non-useful photovoltaic processes occurring at donor/acceptor and electrode interfaces, and finally, elucidation on the key parameters that control the electron-hole binding energies at the donor/acceptor interface and the charge collection at electrode interfaces. Fundamental understanding of the useful and non-useful photovoltaic processes at dynamic donor/acceptor and electrode interfaces will suggest materials synthesis pathways and device engineering that can potentially lead to increased solar energy conversion efficiency in both excitonic, bulk-hetero-junction OPVs and non-excitonic perovskite thin-film PV devices. With respect to education and broadening participation, the proposed activities will also offer interdisciplinary opportunities to enhance class teaching, research training opportunities for students from under-represented groups in science and engineering, and outreach activities for high-school students on the topic of organic polymer based solar cells.