基于钙钛矿/碳纳米管杂化结构的高响应度宽谱光探测器研究

Organolead trihalide perovskite materials are promising candidates for applications in photodetectors due to its high light absorption. However, intrinsic polycrystalline perovskite films still suffer from low carrier mobility and narrow band absorption, limiting their device performance and application potential in broadband photodetectors with high responsivity. Recently, semiconductor-enriched carbon nanotubes have emerged as a potential candidate for broadband photodetector applications due to its tunable relatively narrow bandgap, large light absorption efficiency and high carrier mobility. In this project, combining the advantages of individual building blocks that are perovskites and semiconductor-enriched carbon nanotubes in photodetectors, the perovskite/carbon nanotube hybrid structure is proposed where semiconductor-enriched carbon nanotubes are adopted to significantly enhance the carrier mobility and broaden the absorption spectrum and thus realizing perovskite/carbon nanotube hybrid based broadband photodetectors from the ultraviolet to near-infrared band range with high responsivity. High-quality hybrid crystalline hybrid films with high carrier mobility and high absorption throughout the UV-Vis-NIR region are fabricated and thus implementing phototransistor devices. Gate voltage modulation effects on photo response behaviors are also well studied and finally hybrid perovskite-carbon nanotube broadband photodetectors with high responsivity are obtained. In addition, the energy band diagrams of the perovskite/carbon nanotube hybrid structure are symmetrically investigated and modulated. Moreover, the mechanism of generation, separation and transport of photo-generated carriers are also studied. The project provides a novel route for developing high-performance perovskite based broadband photodetectors from the ultraviolet to near-infrared band range with high responsivity.

钙钛矿材料以其高光吸收在光探测领域具有重要的应用前景。然而，本征多晶钙钛矿薄膜较低的载流子迁移率导致器件的光响应度较低，加上吸收光谱主要集中在紫外-可见波段，很难实现宽光谱高响应度光探测。近来，半导体性碳纳米管以其可调窄带隙、宽谱高光吸收及高载流子迁移率，在宽谱光探测领域显示出突出的优势。本项目拟结合钙钛矿和碳纳米管在光探测方面的优势，构筑钙钛矿/碳纳米管杂化结构，利用碳纳米管提高钙钛矿的载流子迁移率并拓宽其吸收光谱，制备出具有高载流子迁移率、宽谱高光吸收的高质量杂化晶体薄膜，并将其与场效应晶体管结构集成，深入研究栅压调控特性，实现从紫外到近红外波段的高响应度宽谱光探测器。在实现高响应度宽谱光探测器的基础上，系统研究并调控杂化结构的界面能级排列，探索不同波长光照下光生载流子产生、分离与输运机制，揭示微观机制与宏观光电响应之间的关联，为开发高响应度宽谱钙钛矿光探测器提供更多思路和理论依据。

钙钛矿材料以其优异的光电性质在光电探测领域具有重要的应用前景。然而，本征多晶钙钛矿薄膜吸收光谱主要集中在紫外-可见波段，加上其较低的载流子迁移率导致器件的光响应度降低，很难实现宽光谱高响应度光电探测。本项目聚焦于实现高性能钙钛矿基宽谱光电探测器，旨在解决钙钛矿材料目前在实现高响应度宽谱光电探测器方面存在的主要问题，从拓宽材料吸收光谱、提升光生载流子分离以及降低光生载流子复合出发，通过异质复合对光电转换的关键物理过程进行调控，构建了一系列钙钛矿基异质结结构，进而实现了高性能钙钛矿宽谱光电探测器及高集成度钙钛矿探测器阵列。在该研究基础上，拓展了短波红外量子点光电二极管、柔性透明电极的研究工作，为未来硅基集成宽谱成像阵列与柔性宽谱成像阵列提供了良好的技术储备与理论基础。具体研究内容如下：. 一、发展了钙钛矿/硫化铅量子点异质结结构，可实现拓展吸收光谱和提升载流子分离效率的双重作用，构筑并制备了横向光电导和纵向光电二极管型宽谱光电探测器，实现了在365-1550nm宽光谱范围内高响应度、高探测率、快响应速度、高稳定性的光电探测。基于该异质结构光电二极管线阵，设计并实现了板级线阵扫描宽谱成像系统，可实现宽谱成像显示。. 二、发展了钙钛矿/碳纳米管异质结结构光电晶体管，利用半导体性碳纳米管的高载流子迁移率和近红外光谱范围内的高光吸收，结合光电晶体管的栅控特性，实现了高响应度钙钛矿/碳纳米管异质结宽谱光电晶体管。有趣的是该光电晶体管在940nm光照下体现出负光电导现象，可能是由于界面处独特的能级结构导致，未来将对此展开更为深入的研究。. 三、发展了钙钛矿/硫化钼体异质结结构，该体异质结结构可提升光生载流子分离效率，有效降低复合几率，延长光生载流子寿命，结合石墨烯沟道超高载流子迁移率，实现了超高响应度钙钛矿光电晶体管，响应度达到106A/W，同时体现出较高的柔性器件兼容性，柔性化器件与刚性器件性能几乎保持一致。. 四、在上述研究基础上，拓展开发出高密度、低噪声、高外量子效率的硫化铅量子点短波红外光电二极管和实现高性能柔性透明电极的“纳米压印-墨水填充”及“深纹直写-限域生长”技术路线。