基于PFN/Ag光栅背阴极的高响应性能二维钙钛矿光电探测器的研制

The photoelectric detectors based on 3D perovskite have become attracting due to excellent photoelectric response and low production cost, but the poor stability severely limits their applications in practice. Benefit by nanoscale encapsulation of the perovskite layers by the hydrophobic functional group, 2D perovskite materials are much stable than their 3D counterparts in moisture circumstances. However, the layered structure has inhibited the charge transport between different layers and the absorption band is relatively narrow for 2D perovskite, which led to low responsivity for the photodetectors based on 2D perovskites...In this project, we propose to introduce PFN/Ag grating back cathode into the 2D perovskite photodetector using nanoimprint method. The excited surface plasmons (SPs) excited by such grating back cathode have a modulation on the photon absorption distribution and carrier transmission, increasing the number of trapped electrons at the cathode interface for improving the hole injection efficiency, and then achieving high responsivity for the proposed detector. Besides, we will study the interaction between the electric dipole in PFN layer and SPs, and its influence on the dynamic process of charge transfer. It provides theoretical and experimental basis for the development of low-cost and high-performance photodetectors.

基于三维钙钛矿的光电探测器具有优异的光电响应性能且制作成本低，但其环境稳定性差，在实际中应用受到严重限制。相比之下，二维钙钛矿由于引入了具有疏水功能的阳离子可在纳米尺度上对钙钛矿层进行封装，在潮湿环境中的稳定性远优于三维钙钛矿，但其层状结构阻碍了层间电荷的传输，且二维钙钛矿的光吸收波段较窄，导致由其制备的光电探测器响应率偏低。. 本项目提出在二维钙钛矿光电探测器中利用纳米压印法引入复合型PFN/Ag光栅背阴极，利用其激发的表面等离激元（SPs）调控光吸收分布以及载流子的传输性能，增加阴极界面处电子俘获数目以提高空穴注入效率，使探测器实现高响应性能。并研究PFN中电偶极子与SPs共振的相互作用，阐明其对电荷转移中动力学过程的影响机制。为开发低成本、高性能光电探测器提供理论和实验依据。

二维层状钙钛矿的光电性能具有高度可调性，且其机械性能好，在潮湿环境中也具有优良的稳定性，对实现低成本、柔性、高性能光电子器件具有重大潜在研究价值。然而，二维钙钛矿的禁带宽度较大，导致光吸收波段较窄，且受量子尺寸效应限制导致载流子在层间传输受到一定阻碍，故而制约了器件的响应性能。. 本项目所开展的主要研究内容包括：优化研究了平直型二维钙钛矿标准器件中功能层对其响应性能的影响，在并在其基础上，通过引入不同的表面等离激元纳米结构，研制具有宽谱响应的高性能光电探测器，同时并对其光学和电学性能进行研究。. 基于本项目，已发表科技论文 12篇，授权国家发明专利1项，申请国内发明专利 4 项。本项目揭示了活性层厚度对入射光吸收及分布的调控规律，制备了性能优异的薄二维钙钛矿光电探测器。通过引入金属纳米结构并调控其几何参数，研究了其对激发不同表面等离激元共振模式的影响；制备了性能优异的表面等离激元增强型二维钙钛矿光电探测器，并从光电性能、光谱性能及微观形貌等方面对其光电响应性能进行了具体的研究。以此项目为依托，我们还进行了其他相关研究，包括有机光电探测器及全无机钙钛矿纳米晶光电探测器和SiC光电探测器等。本项目的研究对开发高性能的光电子器件具有重要的战略意义。