Unravelling ultrafast charge recombination and transport dynamics in hybrid perovskites.

揭示杂化钙钛矿中的超快电荷复合和传输动力学。

• 批准号: EP/R044481/1
• 负责人: Richard Friend
• 金额: $ 41.85万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FR044481%2F1
• 关键词: Unravelling; ultrafast; charge; recombination; transport

The photoluminescence (PL) efficiency of the hybrid perovskites are exceptionally high for a poly-crystalline semiconductor. I was the first to report this, as exemplified by lasing in vertical cavity structure, and I have gone on to demonstrate that the strong radiative emission is key for the perovskites' exceptional performance in solar cells (power conversion efficiency >20% reported) and light-emitting diodes (external quantum efficiency now >18% in our labs). Future gains will require understanding and control of the non-radiative losses both in the bulk and at the electrodes. Our initial results showed that the PL arises from the recombination of free charges, but new physical concepts are now required to understand how this process can give such unexpectedly high radiative yields, while maintaining low non-radiative losses. The reported long lifetimes bring much longer length scales into play, compared to typical high-emission III-V quantum-well systems. Material inhomogeneity is a central parameter, since electrons and holes sample large volumes before recombination, which potentially changes their physical properties and interactions. State-of-the art PL studies recorded spatially-averaged information with time-resolution around 100 ps, due to challenges in recording local signals on short timescales. Yet, we have found carrier interactions already on sub-picosecond times, which are likely to affect recombination at longer time scales. Probing PL at these fast timescales, will now give insights into a new physical regime. For this, our new technique will combine ultrafast spectrally-resolved PL with spatial microscopy, which will advance the state-of-the art in temporal and spatial resolution by an order of magnitude to sub-picosecond and sub-micrometre regimes. We will use this new setup to study carrier recombination and diffusion in a regime dominated by intrinsic properties (controlled by the carrier-carrier interactions), which will allow us to untangle extrinsic effects (controlled by material properties such as trapping). Simultaneously, local probing will resolve the impact of material morphology on recombination and localisation. Our study will give unprecedented insights into the photo-physics of hybrid perovskites in previously inaccessible, yet highly relevant, temporal and spatial regimes. Our findings will establish a new picture on the physical and material origin enabling the exceptionally-efficient radiative recombination in hybrid perovskites, which will be crucial for unlocking gains in device performance.

对于多晶半导体，杂化钙壶的光致发光（PL）效率异常高。我是第一个举报这一点的人，例如在垂直腔结构中的激光证明了这一点，并且我继续证明，强辐射发射是钙钛矿在太阳能电池中的出色表现的关键（据报道> 20％的电源转换效率> 20％）和光发射diodes（现在的外部量子效率（现在是我们实验室的18％））。未来的收益将需要理解和控制批量和电极中的非辐射损失。我们的最初结果表明，PL是由自由电荷的重组引起的，但是现在需要新的物理概念来了解该过程如何产生如此出乎意料的高辐射产率，同时保持低非辐射性损失。与典型的高排放III-V量子孔系统相比，报道的长寿命使长度尺度更长。材料不均匀性是一个中心参数，因为电子和孔在重组之前采样了大量的大量，这可能会改变其物理特性和相互作用。最先进的PL研究记录了空间平均的信息，其时间分辨率约为100 PS，这是因为在短时间内记录本地信号的挑战。但是，我们已经在亚皮秒二次发现了载体相互作用，这可能会在更长的时间尺度上影响重组。在这些快速时间尺度上探测PL，现在将提供对新物理制度的见解。为此，我们的新技术将将超快分辨的PL与空间显微镜相结合，这将通过临时和空间分辨率的最先进的命中级，并通过一个数量级来降低次秒和亚微米的光度。我们将使用这种新的设置来研究以内在特性（由载流子相互作用控制）支配的载体重组和扩散，这将使我们能够解开外在效应（由诸如陷阱之类的材料特性控制）。同时，局部探测将解决材料形态对重组和定位的影响。我们的研究将在以前无法访问但高度相关的，时间和空间方案中对混合钙化物的光物理学提供前所未有的见解。我们的发现将建立有关物理和物质起源的新图片，从而实现混合钙钛矿中异常效率的辐射重组，这对于解锁设备性能的增长至关重要。

项目成果

Optical control of exciton spin dynamics in layered metal halide perovskites via polaronic state formation.

• DOI: 10.1038/s41467-022-30953-w
• 发表时间: 2022-06-09
• 期刊: Nature communications
• 影响因子: 16.6

Exploiting localized charge accumulation regions in alloyed hybrid perovskites for highly efficient luminescence (Conference Presentation)

利用合金杂化钙钛矿中的局部电荷积累区域实现高效发光（会议演示）

• DOI: 10.1117/12.2543694
• 发表时间: 2020
• 作者: Feldmann S

Charge Carrier Localization in Doped Perovskite Nanocrystals Enhances Radiative Recombination.

• DOI: 10.1021/jacs.1c01567
• 发表时间: 2021-06-16
• 期刊: Journal of the American Chemical Society
• 影响因子: 15
• 作者: Feldmann S;Gangishetty MK;Bravić I;Neumann T;Peng B;Winkler T;Friend RH;Monserrat B;Congreve DN;Deschler F
• 通讯作者: Deschler F

Photodoping through local charge carrier accumulation in alloyed hybrid perovskites for highly efficient luminescence

• DOI: 10.1038/s41566-019-0546-8
• 发表时间: 2020-02-01
• 期刊: NATURE PHOTONICS
• 影响因子: 35
• 作者: Feldmann, Sascha;Macpherson, Stuart;Deschler, Felix
• 通讯作者: Deschler, Felix

Mechanism of carrier localization in doped perovskite nanocrystals for bright emission

掺杂钙钛矿纳米晶中载流子局域化的亮发射机制

• DOI: 10.48550/arxiv.2008.11495
• 发表时间: 2020
• 作者: Feldmann S