Understanding the role of organic ligands on charge transport and photocurrent generation in layered perovskites

了解有机配体对层状钙钛矿中电荷传输和光电流产生的作用

• 批准号: 2892542
• 金额: --
• 依托单位: Imperial College London
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2892542
• 关键词: Understanding; role; organic; ligands; charge

Halide perovskites show great potential for solar energy applications as perovskite solar cells now achieve efficiencies as high as 25.7% for single junction devices.[1] Unfortunately, the rise of perovskite solar cells is hindered by their strong sensitivity to moisture, oxygen, illumination, thermal and bias stresses.[2] Progress in encapsulation technologies alone will not suffice to allow market entry of perovskite solar cells. It is therefore crucial to tackle the question of stability.In order to protect halide perovskite films from moisture, a key trigger of degradation in perovskite-based devices, larger and hydrophobic organic cations (ligands) have been introduced in the crystal lattice.[3] As a consequence, the crystal phase is modified to form a 2D- or layered perovskite structure with slabs of inorganic octahedra separated by ligands. While this modification offers higher environmental stability, it comes at the cost of performance with a drastic loss in solar cell efficiency, in part due to a significant disruption of charge transport and exciton dissociation.[4]In view of this challenge, two research directions are currently being explored: 1) creating a mixed 3D-2D perovskite structure to find a reasonable balance between stability and efficiency;[5] and 2) finding the appropriate ligand to limit its negative impact on efficiency.[6] In this project we will focus on the second aspect and will aim at improving our understanding of the impact of ligands on charge transport and exciton dissociation in layered perovskites. In particular, we will tune the length of the organic ligand and follow its impact on various transport and optoelectronic properties of the semiconducting film. We will also explore the influence of the Van der Waals gap between organic ligands present in the Ruddlesden-Popper phase by comparing its properties with the Dion-Jacobson phase. The goal of this study will be to determine experimentally a maximum ligand size to ensure sufficient coupling between inorganic slabs. In addition, we will ascertain whether the Dion-Jacobson phase should be preferred to the Ruddlesden-Popper one, which is currently the main focus of research efforts in 2D-3D perovskite solar cells.[1] NREL, National Renewable Energy Laboratory. Best Research-Cell Efficiency Chart, 2021. [2] L. Schmidt-mende, et al., APL Mater. 2021, 9, 109202. [3] T. L. Leung, et al., Commun. Mater. 2022, 3, 1. [4] M. S. Holanda, et al., EcoMat 2021, 3, e12124. [5] A. Caiazzo, R. A. J. Janssen, Adv. Energy Mater. 2022, 2202830. [6] H. Fu, J. Mater. Chem. C 2021, 9, 6378.

卤化物钙钛矿在太阳能应用中显示出巨大的潜力，因为钙钛矿太阳能电池现在单结器件的效率高达25.7%。[1]不幸的是，钙钛矿太阳能电池的崛起受到其对水分，氧气，光照，热和偏置应力的强烈敏感性的阻碍。[2]仅仅封装技术的进步不足以让钙钛矿太阳能电池进入市场。因此，解决稳定性问题至关重要。为了保护卤化物钙钛矿薄膜免受水分的影响，钙钛矿基器件中降解的关键触发因素，已在晶格中引入较大的疏水有机阳离子（配体）。[3]因此，晶相被改性以形成2D或层状钙钛矿结构，其中无机八面体的板被配体分开。虽然这种修改提供了更高的环境稳定性，但它是以性能为代价的，太阳能电池效率急剧下降，部分原因是电荷传输和激子解离的显着中断。[4]In鉴于这一挑战，目前正在探索两个研究方向：1）创建混合的3D-2D钙钛矿结构，以找到稳定性和效率之间的合理平衡;[5]和2）找到合适的配体，以限制其对效率的负面影响。[6]在这个项目中，我们将集中在第二个方面，并将旨在提高我们的理解的影响，配体的电荷传输和激子解离层状钙钛矿。特别是，我们将调整有机配体的长度，并遵循其对半导体薄膜的各种传输和光电性能的影响。我们还将探讨的影响，货车德瓦尔斯间隙存在于Ruddlesden-Popper相的有机配体通过比较其性质与狄翁-雅各布森相。本研究的目标是通过实验确定最大配体尺寸，以确保无机板之间的充分耦合。此外，我们将确定Dion-Jacobson相是否应该优先于Ruddlesden-Popper相，后者是目前2D-3D钙钛矿太阳能电池研究工作的主要焦点。[1]NREL，国家可再生能源实验室。最佳研究-电池效率图表，2021年。[2]L. Schmidt-mende等人，APL材料2021年9月109202日。[3]T. L. Leung等人，Commun. Mater. 2022年，3，1。[4]M. S. Holanda等人，EcoMat 2021，3，e12124。[5]A.卡亚佐河A. J. Janssen，Adv. Energy Mater. 2022，2202830。[6]H.福，J。脱线。C 2021，9，6378。