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化学计量比)已经非常成功地进入了下一代光伏电池领域。自那以后，迅速加强的研究活动导致了单结薄膜太阳能电池的认证电力转换效率现在超过了25%。虽然目前存在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日益增长，导致对低成本、高效率解决方案的需求日益增长。尤其是在应对气候变化和能源安全方面，光伏器件的持续发展是迫切需要的，而气候变化和能源安全可以说是人类在下个世纪面临的最大挑战。这个工业案例学习将集中在金属卤化物钙钛矿材料的光电性能和稳定性方面有待解决的关键问题。影响钙钛矿型太阳能电池高效运行的因素将被阐明，包括电子-声子耦合、电荷-载流子迁移率和复合、光发射和重新吸收的机制。此外，这些材料的稳定性将通过对离子迁移和化学转化等因素的严格检查而得到加强，例如在大气条件下。我们将结合使用瞬变吸收、光致发光上转换和太赫兹泵浦探测光谱等超快光学技术，探索基本的光子到电荷转换过程，同时将用X射线衍射和电子显微镜研究化学转换和材料不稳定性。这些研究将直接推动旨在推动创造可商业化的钙钛矿太阳能电池、解决稳定性、带隙可调整性、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。该项目将受益于牛津大学赫兹教授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，他们是钙钛矿型太阳能技术的领先者，目前正在探索其用途，例如，与标准硅太阳能电池相结合。拟议的研究显然符合EPSRC的投资组合，目标是确定的重大挑战物理(纳米级功能材料设计)和化学(定向组装扩展结构与目标特性)。拟议的方案显然也属于EPSRC的物理科学、能源和制造未来；以及能源应用材料、计算和理论化学以及太阳能技术等领域。

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.