新型透明柔性自驱动光电探测器的设计、性能优化和相关物理机制研究

With the rapid development of science and technology, people are constantly pursuing portable, entertaining, healthy and transparent wearable electronic devices, which prompt the further development of transparent and flexible self-powered photodetectors toward high performance, low cost and large area manufacturing. Transparent conductive oxide (TCO) typified by indium tin oxide (ITO) is the most widely used transparent conductive material currently. However, TCO is mostly brittle and easy to break on a flexible substrate. Although conductive polymers have cost advantages, low stability in the air, especially in photodetector light illumination conditions. This project intends to develop a new type of transparent flexible self-powered photodetector based on novel functional materials using transparent and flexible metal nanowires with high specific surface area. It is proposed to adjust the work function by tuning the composition of the metal nanowires, regulating the characteristic wavelength and the characteristic absorption intensity of the LSPR effect of the metal nanowire, novel design of the metal-semiconductor core-shell structure and the three-dimensional metal-semiconductor network core-shell structure. The relationship between the photodetector performances and the structure, size, aspect ratio, composition, surface state and linear density of several metal nanowires and the structure and style of the photodetectors will be investigated in detail. By combining the theoretical simulation, the internal physical mechanism is clarified to realize the high-performance transparent and flexible self-powered photodetectors.

随着科学技术日新月异的发展，人们对便携化、健康化且透明的可穿戴式电子设备不断追求，促使其相应的透明柔性自驱动光电探测器向着高性能、低成本、大面积制造等方向发展。以氧化铟锡（ITO）为代表的透明导电氧化物（TCO）是目前应用最广泛的透明导电材料，然而TCO大多质脆，易在柔性基板上断裂，导电聚合物虽具有成本优势，但其在空气中稳定性较低，尤其在光电探测器工作的光照条件下。本项目拟利用透明柔性、高比表面积的金属纳米线开发新型透明柔性自驱动光电探测器，拟通过改变金属纳米线表面成分调节功函数大小、调控金属纳米线LSPR效应的特征波长和特征吸收强度、设计生长金属-半导体核壳结构和三维金属-半导体网状核壳结构等策略，深入系统研究探测器性能和金属纳米线的结构形貌、尺寸、长径比、表面成分、表面态和线密度、探测器的构成结构等的内在构效关系，结合理论模拟，阐明内在物理机制，实现高性能的透明柔性自驱动光电探测器。

该项目紧紧围绕课题研究的总目标，在透明柔性自驱动光电探测器的设计、性能优化和相关物理机制研究上，开展了较为深入和系统的研究工作，如（1）实现了金属银和多种合金金属纳米线的合成，通过生长条件控制，有效改善了AgNi 核壳纳米线壳层的结晶质量。关注了银纳米线的功函数不匹配问题，首次提出镍包覆提高银纳米线功函数的思路。（2）以透明n-SrTiO3为例，实现了AgNi 核壳纳米线电极与n 型光敏半导体材料之间的肖特基接触及其在透明肖特基光二极管中的应用。AgNi 核壳纳米线材料的高功函数特性使n-SrTiO3 基肖特基光二极管的光电性能显著提升，实现了明显的自驱动短波蓝光探测性能和超快的响应速度，同时保留了SrTiO3 晶片的透明紫外屏蔽性能，使器件同时具有透明紫外屏蔽性能和对短波蓝光的自驱动光电探测性能。（3）实现了仿生透明MXene电极并应用于光电探测器的研究，得到导电性高、透光率高的柔性网络电极，所制备的网络电极方阻不仅低，而且其在250-800 nm波段内透光率接近90%，并基于静电纺丝自支撑TiO2薄膜为例，构筑成了性能优良的紫外光探测器。（4）通过修饰MXene薄膜表面，实现了4种不同功函数的电极材料，以PET 薄膜为衬底，成功应用于柔性光电探测器，该器件以180°被弯曲5000次，仍可保持硅衬底器件电流的80%。在该基金的支持下，以项目申请人为（共同）通讯作者，已经在材料类著名杂志上发表论文20 余篇，与国内外多个课题组开展合作交流研究。该国家基金参与培养5位博士后，2位博士生生和2位硕士生。