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（NCs）由于其优异的性能，其缺陷容忍度超过了传统应用的硫系纳米晶体（例如CuInS2），在众多光电应用中得到了广泛的应用。虽然他们的设备性能引起了极大的关注，但对他们的合成却很少得到认可。通常，nc是通过批量热注射方案合成的，通过该方案，将前体迅速引入含有适当配体的母体溶液中，以触发在毫秒时间尺度内发生的成核和生长。虽然是一种简单的方法，但由于反应进行的速度与注入后达到均匀前驱浓度所需的时间成卷积，合成的nc在尺寸和形态上存在分散性。因此，在结晶的早期阶段缺乏理解，导致对合成的nc控制不良，从而损害光电性能。在本博士学位期间，我们试图探索LHP和钙钛矿启发材料的早期结晶动力学，以评估其控制尺寸和形态演变的内在动力学。同时，我们将其与瞬态光物理测量相结合，以了解生长过程中缺陷的形成。总的来说，我们试图评估限制钙钛矿NCs的合成，结构和性质之间的相互关系，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.