Metal halide perovskites for filterless photodetectors

光电探测器是光通信系统中实现高效光电流转换的关键部件。金属卤化物钙钛矿半导体材料是这项技术的完美匹配，因为它们具有广泛可调的成分，与简单的溶液处理相兼容，再加上它们的强光吸收和高载流子迁移率。在这个项目中，钙钛矿光电探测器将被制造出来，以实现从紫外线（UV）到近红外（NIR）区域的电磁波谱的光探测。这将通过改变钙钛矿的成分来实现带隙工程，并利用我们研究实验室的最新发展来探索以前无法实现的厚吸收层结合一套光电测量，该项目旨在提供暗电流、响应性和探测性的成分和厚度相关数据，从而全面概述这些令人兴奋的材料的结构-加工-性能关系。金属卤化物钙钛矿半导体（PSCs）由于其使用简单的加工方法获得的广泛可调谐的成分，强光吸收和高载流子迁移率，在光电应用中取得了快速进展。目前PSCs的成功主要是由光伏（pv）驱动的，其功率转换效率（pce）现在超过25%相反，钙钛矿光电探测器（PPD），一种基于光电二极管的技术，因此与pv密切相关，没有经历类似的发展轨迹，主要是因为缺乏对如何同时控制二极管整流，外量子效率（EQE）和时间响应等关键器件参数的理解在本项目中，通过调整钙钛矿活性层的组成及其厚度，将制作ppd，以实现电磁波谱从紫外到近红外部分的检测。光电二极管将使用最先进的沉积方法在洁净室条件下制造。ppd的性能将通过在黑暗和光照下的电流电压测量来评估，以评估二极管的整流及其暗电流（Jd）。此外，将进行EQE和特定的探测性测量，以评估器件的光电流转换。这个项目的目的是将i)钙钛矿活性层的成分变化与器件的Jd和ii)厚度变化与光电二极管的Jd相关联。这些方面对于需要低Jd的实际应用来说是至关重要的。Du， T.等。平面钙钛矿太阳能电池的光强和厚度依赖效率：电荷重组与萃取。j .板牙。化学。[C] 2020, 8, 12648.2.]杜涛，等。溶胶辅助溶剂处理：提高钙钛矿太阳能电池性能和稳定性的通用方法，能源工程学报，2017,21(1):1 - 3。郑旭，等。通过配体锚定来管理颗粒和界面，可以实现22.3%效率的倒置钙钛矿太阳能电池。能源学报，2016,32(2):481 - 481。高灵敏度钙钛矿光电探测器的研究进展。j .板牙。化学。中国农业科学学报，2017,39(4):481 - 481（2019）。麦克米金博士等人。串联太阳能电池用混合阳离子卤化铅钙钛矿吸收剂。科学（80-）。351, 151-155（2016）。

Photodetectors are a critical part of optical communication systems for highly efficient light-to-current conversion. Metal halide perovskite semiconductor materials are the perfect match for this technology owing to their broadly tunable compositions, compatibility with simple solution processing combined with their strong light absorption and high charge carrier mobilities. In this project perovskite photodetectors will be fabricated to achieve light detection from the ultra-violet (UV) to the near infra-red (NIR) regions of the electromagnetic spectrum. This will be achieved by bandgap engineering the perovskite through compositional variation and taking advantage of recent developments within our research lab to explore previously unachievable thick absorber layers.1,2 Combined with a suite of optoelectronic measurements the project will aim to deliver composition and thickness related figures of merit for dark current, responsivity and detectivity allowing a holistic overview of structure-processing-property relationships in these exciting materials.Metal halide perovskite semiconductors (PSCs) have seen rapid progress in their optoelectronic applications due to their broadly tunable compositions achieved using simple processing approaches, their strong light absorption and high charge carrier mobility. The current success of PSCs is mainly driven in photovoltaics (PVs), with power conversion efficiencies (PCEs) now in excess of 25%.3 Conversely, perovskite photodetectors (PPD), a technology based on photodiodes and thus closely related to PVs, have not experienced a similar trajectory of growth, mainly due to the lack of understanding of how to simultaneously control critical device parameters such as diode rectification, external quantum efficiency (EQE) and temporal responsivity.4 In this project, by tuning the composition of the perovskite active layer and its thickness, PPDs will be fabricated to achieve detection spanning from the UV to the NIR part of the electromagnetic spectrum. The photodiodes will be fabricated in cleanroom conditions using state-of-the-art deposition methods. The performances of PPDs will be evaluated via current-voltage measurements in the dark and under light illumination to evaluate the rectification of the diodes and their dark-current (Jd). Moreover, EQE and specific detectivity measurements will be carried out to evaluate the light-to-current conversion of the devices. The aim of this project is to correlate i) the composition variation of the perovskite active layer with the Jd of the devices and ii) the thickness variation with the Jd of the photodiodes. These aspects are of the utmost importance for real-world application, where low Jd is desired.1. Du, T. et al. Light-Intensity and Thickness Dependent Efficiency of Planar Perovskite Solar Cells: Charge Recombination versus Extraction. J. Mater. Chem. C 2020, 8, 12648.2. Du, T. et al Aerosol Assisted Solvent Treatment: A Universal Method for Performance and Stability Enhancements in Perovskite Solar Cells, Adv. Energy Mater. 2021, 2101420, 1.3. Zheng, X. et al. Managing grains and interfaces via ligand anchoring enables 22.3%-efficiency inverted perovskite solar cells. Nat. Energy 5, 131-140 (2020).4. Miao, J. & Zhang, F. Recent progress on highly sensitive perovskite photodetectors. J. Mater. Chem. C 7, 1741-1791 (2019).McMeekin, D. P. et al. A mixed-cation lead halide perovskite absorber for tandem solar cells. Science (80-. ). 351, 151-155 (2016).