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

有机-无机金属卤化物钙钛矿（ABX3化学计量学）在下一代光伏电池领域取得了显著的成功。从那时起，一项迅速加强的研究活动已经导致单结薄膜太阳能电池的认证功率转换效率现在超过25%。虽然目前存在这种设备的竞争技术，但世界对能源供应、照明和显示技术日益增长的需求已经创造了对低成本、高效率解决方案的日益增长的渴望。特别是光伏设备的持续进步，迫切需要解决气候变化和能源安全问题，这可以说是人类在未来一个世纪面临的最大挑战。该工业案例研究项目将重点关注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高效运行的因素将被阐明，包括电子-声子耦合机制，电荷载流子迁移和重组，光发射和重吸收。此外，通过对离子迁移和化学转化等因素（例如在大气条件下）的严格检查，这些材料的稳定性将得到增强。基本的光子到电荷转换过程将使用超快速光学技术，如瞬态吸收，光致发光上转换和太赫兹泵浦探针光谱的组合进行探索，而化学转换和材料的不稳定性将通过x射线衍射和电子显微镜进行检查。这些研究将直接为推动商用钙钛矿太阳能电池的创造、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提供支持。该项目将受益于Herz教授在牛津大学的团队在基础材料分析方面的互补专业知识，以及项目合作伙伴牛津光伏公司（Oxford Photovoltaics），后者是钙钛矿太阳能技术的领导者，目前正在探索钙钛矿太阳能技术的应用，例如，与标准硅太阳能电池集成。这项拟议中的研究显然符合EPSRC的投资组合，目标是确定物理学（功能材料的纳米级设计）和化学（具有目标特性的扩展结构的定向组装）方面的重大挑战。拟议的项目也明确属于EPSRC的物理科学、能源和制造业的未来主题；能源应用材料、计算与理论化学和太阳能技术领域。

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.