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很大的潜力，因为钙钛矿太阳能电池现在可实现单个连接装置的效率高达25.7％。[1]不幸的是，钙钛矿太阳能电池的兴起受到对水分，氧，照明，热和偏置应力的强烈敏感性。[2]仅封装技术的进展就不足以允许钙钛矿太阳能电池的市场进入。因此，要解决稳定问题至关重要。为了保护卤化物钙钛矿膜免受水分的侵害。结果，将晶相修饰以形成2D或分层的钙钛矿结构，并用配体分离的无机八面体的平板。虽然这种修改提供了更高的环境稳定性，但它以绩效成本造成了太阳能电池效率的巨大损失，部分原因是电荷运输和激子解离的大量中断。[4]鉴于目前正在探索这一挑战，目前正在探索两个研究方向：1）在稳定稳定性和效率之间找到合理的平衡效果和2 [5]；效率。[6]在这个项目中，我们将重点关注第二方面，并将旨在提高我们对配体对分层钙钛矿中电荷运输和激子解离的影响的理解。特别是，我们将调整有机配体的长度，并遵循其对半导体膜的各种传输和光电特性的影响。我们还将通过将其特性与狄翁 - 雅各布森相比较，探讨ruddlesden-popper阶段中存在的有机配体之间的范德华差距的影响。这项研究的目的是通过实验确定最大配体尺寸，以确保无机板之间的足够耦合。此外，我们还将确定是否应优先于Ruddlesden-Popper One，这是2d-3d Perovskite太阳能电池的主要研究重点。[1] NREL，国家可再生能源实验室。最佳研究细胞效率图，2021。[2] L. Schmidt-Mende等人，APL Mater。 2021，9，109202。[3] T. L. Leung等，Commun。母校。 2022，3，1。[4] M. S. Holanda等人，Ecomat 2021，3，E12124。 [5] A. Caiazzo，R。A。J. J. Janssen，Adv。能源母校。 2022，2202830。[6] H. Fu，J。Mater。化学C 2021、9、6378。