Optoelectronic properties and stability of next-generation perovskite materials for solar cells

有机-无机金属卤化物钙钛矿（ABX 3化学计量）已经非常成功地进入下一代光伏电池领域。一个迅速加强的研究活动，导致认证的功率转换效率现在超过25%的单结薄膜太阳能电池。虽然目前存在用于此类设备的竞争技术，但世界对能源供应、照明和显示技术的需求不断增长，这使得人们越来越希望获得低成本、高效率的解决方案。特别是，迫切需要光伏器件的持续进步，以应对气候变化和能源安全，这可以说是人类在即将到来的世纪面临的最大挑战。这个工业案例学生将集中在关于金属卤化物钙钛矿的光电性能和稳定性方面有待解决的关键问题。影响钙钛矿太阳能电池有效运行的因素将是阐明，包括电子-声子耦合，电荷载流子迁移率和复合，光发射和再吸收的机制。此外，这些材料的稳定性将通过对诸如在大气条件下的离子迁移和化学转化等因素的严格检查来增强。基本的光子到电荷转换过程将使用超快光学技术的组合进行探索，例如瞬态吸收，光致发光上转换和太赫兹泵浦探测光谱，而化学转换和材料不稳定性将用X射线衍射和电子显微镜检查。这些研究将直接投入到旨在推动商业化钙钛矿太阳能电池的创建，解决稳定性，带隙可调性，无铅钙钛矿，无陷阱材料，材料形态控制和多结器件结构的合作努力中。该项目将受益于Herz教授在牛津大学的基础材料分析小组以及项目合作伙伴Oxford Photophorics的互补专业知识，Oxford Photophorics是钙钛矿太阳能技术的领导者，目前正在探索其用途，例如与标准硅太阳能电池相结合。在物理学（功能材料的纳米级设计）和化学（定向组装具有目标特性的扩展结构）中确定了重大挑战。拟议的计划也明显属于物理科学，能源和制造未来的EPSRC主题福尔斯;和能源应用，计算和理论化学和太阳能技术的材料领域。

Organic-inorganic metal halide perovskites (ABX3 stoichiometry) have made a remarkably successful entry into the field of next-generation photovoltaic cells. A rapidly intensifying research activity has since led to certified power conversion efficiencies now exceeding 25% for single-junction thin-film solar cells. While competing technologies currently exist for such devices, the world's growing need for energy supply, lighting and display technologies has created an increasing desire for low-cost, high-efficiency solutions. Continued advances in photovoltaic devices, in particular, are urgently required to address climate change and energy security, which are arguably the greatest challenges to be faced by mankind over the coming century.This Industrial CASE Studentship will focus on critical issues remaining to be resolved regarding the optoelectronic performance and stability of metal halide perovskites.Factors that influence the efficient operation of perovskite solar cells will be elucidated, including mechanisms for electron-phonon coupling, charge-carrier mobility and recombination, light emission and re-absorption. In addition, the stability of these materials will be enhanced through critical examination of factors such as ionic migration and chemical conversion, e.g. under atmospheric conditions. Fundamental photon-to-charge conversion processes will be explored using a combination of ultra-fast optical techniques, e.g. transient absorption, photoluminescence up-conversion and THz pump-probe spectroscopy, while chemical conversions and material instabilities will be examined with x-ray diffraction and electron microscopies. These studies will feed directly into collaborative efforts aimed at propelling forward the creation of commercially available perovskite solar cells, addressing stability, band-gap tunability, lead-free perovskites, trap-free materials, material morphology control and multi-junction device structures. The project will benefit from the complementary expertise of Prof Herz's group at the University of Oxford on fundamental materials analysis, and of the project partner, Oxford Photovoltaics, who are leaders in perovskite solar technology and are currently exploring their use, for example, integrated in tandem with standard silicon solar cells.The proposed research clearly fits within the EPSRC's portfolio, targeting identified Grand Challenges in Physics (Nanoscale Design of Functional Materials) and Chemistry (Directed Assembly of Extended Structures with Targeted Properties). The proposed programme also clearly falls into the EPSRC Themes of Physical Sciences, Energy & Manufacturing the Future; and the Areas of Materials for Energy Applications, Computational and Theoretical Chemistry and Solar Technology.