石墨烯与有机金属钙钛矿复合光增益材料的制备及其光探测性能研究

Graphene shows more features in highly sensitive detection because of its high mobility, ballistic transport, tunable wettability, and so on; but it lack optical gain mechanism due to poor light absorption cross-section and fast recombination rate between photon-generated carriers. Additional, organometal halide perovskite is an excellent light absorber because of its highly broadband absorption, long charge-carrier lifetime, long charge-carrier diffusion length, and so forth. But it still faces the challenges of high trapping density, low electron–hole separation yield and poor operational stability. Therefore, if integrating hybrid of graphene and perovskite to take full advantage of their synergetic effect, such as photogating effect, we will design new type of optical absorption material with high gain, and novel photoelectric detector. Then basing on defect engineering, interface engineering and band gap engineering in this project, we will preparate hybrid gain materials, then fabricate high quality field-effect transistor when using graphene and its derivatives act as channel layer, active layer additive and interface layer. We will research effective separation efficiency of photogenerated electron-hole, explore photogating effect induced performance enhancement mechanism in high optical gain and high sensitive field-effect transistor, analyze channel carrier-transport efficiency, modulate optical absorption band of photoactive material，enhance its structure order, and then fabricate new type photodector. Ultimately, the project will reveal the new physical phenomena of synergetic effect derived from hybrid system, and will theoretically and technically support for the fabrication of with extra-high sensitivity and ultrabroadband detection, and will also acquire original research findings.

石墨烯因高迁移率、弹道输运、可调浸润性等特性，在高灵敏探测中倍显特色，但由于弱光学吸收、快复合速率而缺乏光增益机制。有机金属卤化物钙钛矿因具有高宽带光吸收、长载流子寿命、大扩散长度等特性，是优异的光吸收材料；但存在俘获密度高、载流子分离效率低、稳定性差等问题。若将两种材料集成，基于协同效应，如光选择效应，就可设计出高增益光吸收材料及新型光电探测器。本项目基于缺陷工程、界面工程及能带工程，制备高质量的光增益复合材料；并利用石墨烯及其衍生物充当沟道层、活性层添加剂及界面层，构建高效率的场效应晶体管。研究光生电荷有效分离机制，探索在高光增益及高灵敏性的场效应晶体管中光选择效应诱导的性能增强机制，分析沟道载流子的输运效率，调制活性层光吸收波段，促进其结构有序，构建新型光电探测器。项目将揭示复合体系协同效应的新物理现象，为构建高灵敏度且宽谱探测的光探测器提供理论和技术支撑，并获得原创性研究成果。

项目背景与研究内容：制备高质量有机无机卤化物钙钛矿与石墨烯的复合功能材料；采用缺陷工程、界面工程、能带工程等三大工程，构建高灵敏性的场效应晶体管；研究复合功能材料的物性及其场效应晶体管的特性研究；研究协同效应促进的新物理现象及器件性能增强的工作机制研究。.研究结果：石墨烯诱导钙钛矿结晶，Ag-rGO钝化钙钛矿缺陷且因Ag离子的等离激元效应，其协同效应增强了钙钛矿薄膜光吸收，进而显著提升光响应，超过3个数量级，但较大的噪声电流也限制了较低的比探测率。并基于高迁移率大面积石墨烯的研发需求，开发了单晶<111>铜箔的制备工艺及大面积单晶石墨烯的制备工艺。同时为制备稳定钙钛矿的研发需求，开发了二维RP钙钛矿及其光电探测器，开展了迁移率工程与DOS工程研究，使其实现了协同调控增强了RP钙钛矿的光电探测性能。.科学意义：高品质大面积石墨烯的构建为碳基电子学器件奠定继续深入研究的潜力；RP钙钛矿作为量子阱超晶格结构，可通过有机层调控，来实现介电特性、铁电特性、光电特性的调控，进而开发各类光电敏感的探测器件。