Kinetic data-driven development of light-interacting materials

在过去的5年中，卤化铅钙钛矿（LHP）纳米晶体（NC）由于其优异的性能而在许多光电应用中得到了广泛的应用，其缺陷容限超过了传统应用的硫属化物NC（例如，CuInS2）。虽然人们对它们的器件性能给予了极大的关注，但很少有人对它们的合成给予认可。通常，使用分批热注入方案合成NC，通过该方案将前体快速引入到含有适当配体的母液中，以触发以毫秒时间尺度发生的成核和生长。尽管这是一种简单的方法，但由于反应进行的速度与注射后实现均匀前体浓度所需的时间的卷积，合成的NC在尺寸和形态上具有分散性。因此，在结晶的早期缺乏理解使得对合成的NC的控制较差，从而损害光电性能。在这个博士学位期间，我们试图探索LHP和钙钛矿启发材料的早期结晶动力学，以评估它们在控制尺寸和形态演变方面的内在动力学。在串联，我们耦合这与瞬态电子物理测量，以获得在生长过程中的缺陷形成的理解。总的来说，我们试图评估受限钙钛矿NC的合成，结构和性能的相互关联关系，为更广泛的光电应用中的受控合成铺平道路。

Over the past 5 years, lead halide perovskite (LHP) nanocrystals (NCs) have observed extended use in a multitude of optoelectronic applications due to their outstanding properties of which defect tolerance out competes traditionally applied chalcogenides NCs (e.g., CuInS2). Whilst significant attention has been drawn to their device performance, little recognition is paid towards their synthesis. Typically, NCs are synthesised using a batchwise hot injection protocol by which a precursor is swiftly introduced into the mother solution, containing appropriate ligands, to trigger nucleation and growth which takes place at millisecond timescales. Albeit a facile method, as-synthesised NCs suffer from dispersity in size and morphology due to the velocity at which the reaction proceeds in convolution with the time required to achieve uniform precursor concentration following injection. As a result, absence of understanding during earlier times in crystallisation renders poor control over as synthesised NCs thus detrimental optoelectronic performance. During this PhD, we attempt to probe early crystallisation kinetics of LHP and perovskite inspired materials to assess their intrinsic kinetics in governing the evolution of size and morphology. In tandem, we couple this with transient photophysical measurements to gain an understanding of defect formation during growth. Overall, we attempt to assess the interconnected relationship of synthesis, structure, and properties of confined perovskite NCs paving the way for controlled synthesis in wider optoelectronic applications.