喷墨打印p-i-n型同质结钙钛矿窄带多光谱探测器及其光电特性研究

Narrowband multispectral photodetectors have demonstrated their huge potential and promising applications in the areas of national defense, machine vision, internet of things, medical chemistry, food safety etc.. Based on the outstanding optoelectronic properties of the organic-inorganic perovskite materials, in recent years, research projects concerning the perovskite narrowband multispectral photodetectors become the cutting-edge topics. However, for further development, several bottleneck issues should be overcome including the slow response speed, relatively low external quantum efficiency (EQE), and difficult to integrate on one chip. We propose this project to deal with those bottleneck issues mentioned above. The key creativity is to construct the perovskite p-i-n homojunction within the active layer through the means of deposition p-type saturated perovskite solution on top of the cured n-type perovskite thin film. On the basis of the p-i-n homojunction, a new narrowband multispectral photodetector will be built to demonstrate our ideas. Besides, opto-electrical models will be construct to unravel the hidden mechanism of the dissociation, transportation, and collection of the photogenerated charge carriers. Focus will be put on the explanation of the influence of the p-i-n homojunction on enhanced dissociation and fast transportation of the photogenerated charge carriers. The mechanism of improvement of EQE and increased response speed of the photodetector will also be discussed in details. Within this project, the device structure and fabrication techniques will be optimized. Through inkjet printing method, flexible and multispectral response photodetector will be realized for large-scale and on-chip integration. This project targeting at fast response, high efficiency, and flexible narrowband multispectral photodetectors whose fruitful results will provide technical support and theoretical guidance for the next generation photodetector.

窄带多光谱探测技术在国防、机器视觉、物联网、医药化学、食品安全等领域具有巨大应用前景。基于钙钛矿材料的优异光电特性，近年来新型钙钛矿窄带多光谱探测器已成为该领域新兴前沿方向，但目前仍存在外量子效率低、响应速度慢、多光谱响应难以同时片上集成等难点。本课题围绕上述关键问题开展研究，建立通过p型（饱和溶液）和n型（膜）钙钛矿界面相溶结合构筑p-i-n型钙钛矿同质结的新方法，实现可控制备；构建基于p-i-n型钙钛矿同质结的新型窄带多光谱光电探测器，建立光电耦合模型，阐明光生载流子产生、分离、输运、收集的机理与途径，阐明p-i-n型钙钛矿同质结对加强载流子分离和加速载流子输运的影响，及其对提升器件外量子效率和响应速度的作用机理；优化器件结构设计和制备工艺，并通过喷墨打印技术实现柔性多光谱响应器件片上集成。本项目的研究将为高效率、快响应柔性钙钛矿窄带多光谱探测器的研制提供理论支持和技术指导。

窄带多光谱探测技术在国防、机器视觉等领域具有巨大应用前景。基于钙钛矿材料的优异光电特性，近年来新型钙钛矿光电探测器已成为该领域新兴前沿方向，但目前仍存在外量子效率（EQE）低、可靠性较差等难点。本课题围绕上述关键问题开展研究，提出了在钙钛矿光电探测器结构内部远离光入射一侧构建内建电场加速载流子分离和输运进而提升器件性能的策略。该策略适用于正、倒置等器件结构，兼容多种传输层与有源层材料组合，适用范围广泛。建立了退火温度、时间与前驱体比例等钙钛矿掺杂类型(P、N型)与浓度的调控手段，进而控制钙钛矿界面内建电场的方向与强度，实现可控制备；构建适用于钙钛矿窄带多光谱光电探测器的光电耦合模型，阐明光生载流子产生、分离、输运、收集的机理与途径，揭示内建电场的强度与方向对加强载流子分离和加速载流子输运及其对提升器件EQE和响应速度的作用机理；开发了逆向纳米光子学优化算法，设计亚波长光栅结构，实现对目标响应波长的精细光场调控，获得钙钛矿多光谱窄带吸收；开发了适用于喷墨打印技术的二元溶剂（十二烷和辛烷）型钙钛矿纳米晶墨水，并通过调控喷墨打印工艺参数与后处理工艺，获得均匀平整（均方根粗糙度仅为0.7nm）的钙钛矿薄膜；优化器件结构和制备工艺，实现正、倒置等多种结构的光电探测器性能的显著提升（550nm处获得EQE为83.51%，为已有报道的最高值之一），并具有超过1600小时的EQE稳定性（倒置器件可保持EQE初始值90.92%，正置器件可保持EQE初始值的97.6%）。本项目的研究为高效率、窄带多光谱钙钛矿探测器的研制提供理论支持和技术参考。依托本项目，发表SCI论文（同为EI收录）8篇，EI会议论文1篇（影响因子IF>17论文3篇），其中项目负责人作为第一作者发表Advanced Science封底论文1篇（被广东省高校科研工作简报收录）、3篇为共同第一作者、8篇作为通讯作者；发表EI会议论文1篇，并获得2022年IEEE ICET Best Student Paper Award (第五届IEEE电子技术国际会议最佳学生论文奖, 获奖率2.3%, 6/257) ; 申请发明专利4项，授权1项。