Ultra-fast interfacial charge transfer probed using a core-hole clock implementation of resonant inelastic x-ray scattering (RIXS)

使用共振非弹性 X 射线散射 (RIXS) 的芯孔时钟实现探测超快界面电荷转移

基本信息

批准号：
EP/T004355/1
负责人：
James O'Shea
金额：
$ 2.67万
依托单位：
University of Nottingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2019
资助国家：
英国
起止时间：
2019 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FT004355%2F1
关键词：
Ultra fast interfacial charge transfer

项目摘要

Ultra-fast electron transfer between a molecule and a surface to which it is coupled plays a key role in light-harvesting devices such as dye-sensitised solar cells and water-splitting photoelectrochemical cells (the model water splitting photoanode shown in figure 1 being a prime example). An elegant way to probe these charge transfer processes, which typically happen on the low femtosecond timescale is the use of resonant core-level spectroscopy in the form of resonant photoemission (RPES). This non-radiative core-hole decay technique relies on monitoring the photoelectrons emitted when a resonantly excited electron participates in the core-hole decay. But these have a very limited escape depth so the technique can only be applied to systems where the charge transfer interface is the surface. In principle, the photons emitted during core-hole decay carry the same information. The corresponding radiative technique is known as resonant inelastic x-ray scattering (RIXS).The aim of this proposal is to realise a novel core-hole clock implementation of resonant inelastic x-ray scattering (RIXS) to probe the electron transfer from specific unoccupied molecular orbitals of a dye molecule into the conduction band of a surface to which it is adsorbed. Using this method we should be able to probe charge transfer dynamics on the timescale of the core-hole lifetime (a few femtoseconds) in the same way as resonant photoemission (RPES), only here we are using a photons-in, photons-out technique. This approach is a very promising route to probing ultra-fast charge transfer in realistic systems where the charge transfer interface of molecular devices such as solar cells are typically buried by a transport layer or electrolyte. The series of synchrotron experiments described in this overseas travel grant proposal aim to obtain the data for a definitive reconciliation of the core-hole clock implementations of both RPES and RIXS, and the application of the latter to a buried charge transfer interface.

分子与其耦合表面之间的超快电子转移在染料敏化太阳能电池和水分解光电化学电池（图 1 中所示的模型水分解光阳极）等光捕获装置中发挥着关键作用。主要例子）。探测这些电荷转移过程（通常发生在低飞秒时间尺度）的一种优雅方法是使用共振光电子发射（RPES）形式的共振核心级光谱。这种非辐射核空穴衰变技术依赖于监测当共振激发电子参与核空穴衰变时发射的光电子。但它们的逃逸深度非常有限，因此该技术只能应用于电荷转移界面为表面的系统。原则上，芯空穴衰变过程中发射的光子携带相同的信息。相应的辐射技术被称为共振非弹性 X 射线散射 (RIXS)。该提案的目的是实现共振非弹性 X 射线散射 (RIXS) 的新型芯孔时钟实现，以探测来自特定未占据原子的电子转移。染料分子的分子轨道进入其吸附的表面的导带。使用这种方法，我们应该能够以与共振光电子发射（RPES）相同的方式在芯空穴寿命的时间尺度（几飞秒）上探测电荷转移动力学，只是在这里我们使用光子输入，光子输出技术。这种方法是探测现实系统中超快电荷转移的一种非常有前途的途径，在现实系统中，分子器件（例如太阳能电池）的电荷转移界面通常被传输层或电解质掩埋。该海外旅行资助提案中描述的一系列同步加速器实验旨在获取数据，以最终协调 RPES 和 RIXS 的核心空穴时钟实现，以及后者在埋藏电荷传输接口中的应用。