Metal halide perovskites for filterless photodetectors

光电探测器是光通信系统中实现高效光流转换的关键部件。金属卤化物钙钛矿半导体材料是这项技术的完美匹配，因为它们的组成广泛可调，与简单的溶液处理兼容，并具有强大的光吸收和高载流子迁移率。在这个项目中，将制作钙钛矿型光电探测器，以实现从电磁光谱的紫外线(UV)到近红外(NIR)区域的光探测。这将通过对钙钛矿进行带隙工程来实现，通过成分变化，并利用我们研究实验室内的最新发展来探索以前无法实现的厚吸收体层。1，2结合一套光电测量，该项目的目标是提供与暗电流、响应度和探测率相关的成分和厚度相关的优值系数，从而全面了解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)由于其组成可通过简单的加工方法实现广泛可调，其强大的光吸收和高电荷载流子迁移率，在其光电应用方面取得了快速进展。PSCS目前的成功主要是在光伏(PV)中驱动的，功率转换效率(PCE)现在超过25%。3相反，钙钛矿型光电探测器(PPD)，一种基于光电二极管的技术，因此与PV密切相关，没有经历类似的增长轨迹，主要是由于缺乏了解如何同时控制关键的器件参数，如二极管整流、外部量子效率(EQE)和时间响应。4在本项目中，将通过调节钙钛矿有源层的组成和厚度，制造PPD，实现从电磁光谱的UV到近红外部分的探测。光电二极管将在洁净室条件下使用最先进的沉积方法制造。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情况及其暗电流(JD)。此外，还将进行EQE和特定的探测率测量，以评估器件的光到电流转换。本项目的目的是将钙钛矿型有源层的成分变化与器件的JD和II)厚度的变化与光电二极管的JD相关联。这些方面对于实际应用是极其重要的，在现实世界中，需要低JD 1。Du，T.等人。平面钙钛矿太阳能电池的光强和厚度相关效率：电荷复合与提取。J.Mater化学。C 2020年，8,12648.2。Du，T.et al气溶胶辅助溶剂处理：一种提高钙钛矿型太阳能电池性能和稳定性的通用方法，高级能源材料。2021年，2101420，1.3.郑X.等人。通过配基锚定控制颗粒和界面，实现了22.3%效率的倒置钙钛矿太阳能电池。纳特。能源5,131-140(2020)。苗军，张福，高灵敏度钙钛矿型光电探测器的最新进展。J.Mater化学。C7,1741-1791(2019).McMeekin，D.P.等人.一种用于串联太阳电池的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).