Crystal domain size control in organometal halide perovskite materials and its effect on ion and defect migration as well as its optoelectronic properties for photovoltaic application

有机金属卤化物钙钛矿材料的晶域尺寸控制及其对离子和缺陷迁移的影响及其光伏应用的光电性能

• 批准号: 395191217
• 负责人: Professorin Dr. Anna Köhler, since 3/2019
• 金额: --
• 依托单位: Lehrstuhl für Experimentalphysik II (Optoelektronik weicher Materie)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/395191217?language=en
• 关键词: Crystal; domain; size; control; organometal

Perovskite materials based on organometal halides, such as methylammonium lead iodide (MAPI) found a lot of attention within the solar energy community in the very recent time. Their development in reported device efficiency is unprecedented, starting with an efficiency of around 3% in 2012 of more than 21% recently. Their general elemental abundancy and potential viability for low cost solution processing make them a very promising candidate for 3rd generation photovoltaics, but also light emitting devices. Despite this quick development, there are still many fundamental question remaining. We have shown that surprisingly high crystalline semiconductor qualities are achievable, however, the effect of grain boundaries and their overall effect on stability, trap states, disorder, ion and defect state migration has not completely understood. Object of this proposal is the control of crystalline domain sizes in a wide range within the perovskite films, and to investigate the subsequent effects on its optoelectronic properties. The first part of this project focuses on the crystal size control of organometal halide crystallites in thin films and their related mechanism for crystal growth. We will establish a method how to control the crystallisation kinetics and the crystal grain sizes on a very broad range using controlled atmospheres of selected solvent vapour. With this method we directly influence the crystallisation process, nucleation density and coalescence without having to alter precursor compositions. The aim is to provide a precise control of crystallite sizes on a broad range from nanometres to several tens of micrometers. Spectroscopic and microscopic methods track the respective results and kinetics. In-situ structural characterisation using X-ray scattering will be a second part of this project and will give precise information on the kinetics of crystallisation. The third part of this project focuses on the electro-optical characterisation and creates the ultimate relation to grain sizes. Specifically, this project will employ temperature dependent current transients, which allow an understanding for ion migration and hysteresis, as well as optical techniques such as absorption and photoluminescence spectroscopy as well as wide-field photoluminescence microscopy. Additional methods such as electro-absorption and photoelectron-spectroscopy, which are and will be established in my research group, are available as well. Combining these methods we can address the influence of grain boundaries on ion and defect migration, trap states and disorder as well as solar cell device performance, i.e. hysteresis, stability and charge recombination. This will provide a deep fundamental understanding on the thin film and material properties, and create respective design and processing rules for organometal halide perovskite semiconductors for their application in solar cells and related devices.

基于有机金属卤化物的钙钛矿材料，例如甲基碘化铅铵（MAPI），最近在太阳能界引起了广泛关注。据报道，他们的设备效率取得了前所未有的发展，从 2012 年的 3% 左右的效率开始，最近已超过 21%。它们的元素丰度和低成本溶液加工的潜在可行性使它们成为第三代光伏发电以及发光器件的非常有前途的候选者。尽管发展迅速，但仍然存在许多基本问题。我们已经证明，可以实现令人惊讶的高晶体半导体质量，但是，晶界的影响及其对稳定性、陷阱态、无序、离子和缺陷态迁移的总体影响尚未完全了解。该提案的目的是在钙钛矿薄膜内大范围内控制晶域尺寸，并研究对其光电性能的后续影响。该项目的第一部分重点研究薄膜中有机金属卤化物微晶的晶体尺寸控制及其相关的晶体生长机制。我们将建立一种方法，如何使用选定溶剂蒸汽的受控气氛在非常宽的范围内控制结晶动力学和晶粒尺寸。通过这种方法，我们可以直接影响结晶过程、成核密度和聚结，而无需改变前体成分。目的是在从纳米到几十微米的广泛范围内提供对微晶尺寸的精确控制。光谱和显微方法追踪各自的结果和动力学。使用 X 射线散射进行原位结构表征将是该项目的第二部分，并将提供有关结晶动力学的精确信息。该项目的第三部分重点关注电光表征并创建与晶粒尺寸的最终关系。具体来说，该项目将采用与温度相关的电流瞬变，从而可以了解离子迁移和滞后现象，以及吸收和光致发光光谱等光学技术以及宽视场光致发光显微镜。还可以使用其他方法，例如电吸收和光电子能谱，这些方法已经并将在我的研究小组中建立。 结合这些方法，我们可以解决晶界对离子和缺陷迁移、陷阱状态和无序以及太阳能电池器件性能（即磁滞、稳定性和电荷复合）的影响。这将为薄膜和材料特性提供深入的基础了解，并为有机金属卤化物钙钛矿半导体在太阳能电池和相关器件中的应用创建相应的设计和加工规则。