低温层层组装柔性钙钛矿太阳电池用AZO-CH3NH3PbI3异质结及其电荷传输机理研究

This project assemble the controllable micro-nano structure and adjustable thickness of AZO/ZnO-CH3NH3PbI3 heterostructures for perovskite solar cell on flexible substrate using atomic layer deposition, combines high-energy ball milling and spin-coating method, to improve collection capacity and reduce the compound of photogenerated electrons and holes, and improve the optical and electrical properties of the flexible perovskite-type solar cells, thus to obtain low cost and excellent optical properties, and the preparation method of large area flexible perovskite-type solar cell heterostructures, provide reliable and technical support for the popularization and application of perovskite-type solar cell. The effect of atomic layer deposition and high energy ball-milling parameters on the micro-and nano-structures and thickness, band structure properties of ZnO-CH3NH3PbI3 and AZO thin films have been investigated. The phase composition, thickness, combined state, distribution, carrier density and photoelectric properties of AZO/ZnO-CH3NH3PbI3 heterostruction have been analyzed by using XPS, XRD, SEM, AFM, Hall Tester and electro-optical test systems. The effect of characteristics of AZO/ZnO-CH3NH3PbI3 heterostructures on its optical and electrical properties has been investigated. The electron transport model have been established, and the charge transport mechanism of perovskite-type solar cell have been revealed.

本项目采用原子层沉积法、高能球磨法和旋涂法相结合，在柔性基体表面层层组装微纳结构可控、厚度可调的钙钛矿太阳电池用AZO/ZnO-CH3NH3PbI3异质结，来提高电子收集能力，降低光生电子与空穴的复合，进而提高柔性钙钛矿太阳电池的光电性能，从而得到成本低、光电性能优异、可大面积实施的柔性钙钛矿太阳电池异质结制备新技术，为钙钛矿太阳电池推广应用提供可靠的理论基础与技术支持。系统研究原子层沉积和高能球磨工艺参数对所得AZO和ZnO-CH3NH3PbI3薄膜微纳结构、厚度、能带结构等影响规律。采用 XPS、XRD、SEM、AFM、霍尔测试仪、光电测试系统等测试分析AZO/ZnO-CH3NH3PbI3异质结的相组成、厚度、结合状态、分布、载流子浓度和光电等性能，探讨AZO/ZnO- CH3NH3PbI3异质结特性对光电性能影响规律，建立异质结电子传输模型，揭示钙钛矿太阳电池中电荷传输机理。

有机无机杂化卤化物钙钛矿材料是目前太阳能电池领域的研究热点之一。钙钛矿太阳能电池通常由电子传输材料，空穴传输材料，钙钛矿吸收层以及电极组成。电子传输材料和钙钛矿吸收层的深入研究对于钙钛矿太阳能电池性能进一步提升有重要意义。通过系统研究ZnO、AZO电子传输层，采用MOF为宿主和自牺牲模板的策略将ZnO与金属纳米颗粒相结合，形成Ag嵌入多孔ZnO的金属/半导体界面结构，有利于减少界面电阻并促进电子传输效率；通过SnCl2、SrCl2、含N化合物C3N4改性来调节CH3NH3PbI3材料电子结构和缺陷结构，优化了对PbI2的浓度、MAI的浓度、钙钛矿退火温度、时间、不同溶剂、添加剂含量等工艺参数；采用 XPS、AFM、中子反射数据、霍尔测试仪、光电测试系统等分析研究材料微观结构和性能演变规律，揭示钙钛矿异质结结构特性对光-电转换性能的影响和电荷传输机理，研究表明膜层界面处原子结合紧密，抑制了钙钛矿材料中的劣态离子、分子的扩散，促进了光激发电荷的分离，氮化碳p-C3N4的界面电荷转移行为使钙钛矿中的电子更容易被提取，提高了活性光生电子的比例，其界面电荷转移速率为ket=2.83×109 s-1，进而设计和制备了不同结构和厚度的强度高、耐热性好和环境适应强于一体的无机有机杂化钙钛矿复合材料，为长寿命高性能太阳能电池材料研制、选材、优化及其光电性能科学决策提供可靠基础。本项目在完成过程中，在J Mater. Chem. A, ACS Appl. Mater. Interfaces等杂志发表SCI论文10篇，获得国家发明专利6项，获得省部级奖励1项。本项目研究已顺利完成，达到预期目标。