柔性钙钛矿太阳能电池新型器件的构建及其光伏特性研究

The aim of this project is to construct novel flexible perovskite solar cells (PSCs) on metal Ti substrate, then, an all-solution-processed route will be used for cell fabrication. Around this novel flexible PSCs, we will focus our investigations on the transparent electrode and the metal substrate. According to solar cell structure, we will use the solution route to fabricate Ag nanowires into transparent electrode and then improve its transparency and conductivity simultaneously by optimizing its micro-structure, meanwhile, we will minimize its roughness factor. We will investigate the mechanism through which the micro-structure of transparent electrode affects the collection of holes. By optimizing the micro-structure and adding interfacial buffer layer, the collection efficiency of holes is expected to be improved. Novel transparent electrode will be prepared by compositing Ag nanowires with AZO nanoparticles and W18O49 nanowires that can reduce the wire-to-wire junction resistance. This novel electrode will be applied into our flexible PSCs. By chemical routes, TiO2 compact and porous films will be in-situ constructed on Ti substrate. For TiO2 compact film, the study will reveal the influence of its thickness, crystallinity, and surface defects on the photovoltaic properties of PSCs. For TiO2 porous film, we will investigate how the nano-structure affects the photovoltaic performance and kinetic processes like the separation of photo-generated carriers, transport of electrons, charge recombination, and so on.

本项目拟在Ti衬底上构建新型柔性钙钛矿太阳能电池（PSCs），并采用全溶液法制备电池器件。围绕新型器件，我们重点研究透明电极和金属衬底的功能结构调控，揭示其微观结构对载流子收集动力学过程的影响机制。根据金属基PSCs结构特征，拟首先使用溶液法制备Ag纳米线透明电极，通过微观结构调控同时提高其透光性和导电性，并降低其表面粗糙度。研究透明电极微观结构对空穴收集的影响机制，通过优化结构并加入界面缓冲层提高空穴收集效率。将性能优异的W18O49纳米线与AZO纳米粒子以及Ag纳米线进行复合制备新型透明电极，通过降低线-线之间结电阻提高透明电极电导率，并将其应用于金属基柔性PSCs。通过化学法在金属Ti衬底上原位构建TiO2致密膜和多孔膜，研究TiO2致密膜厚度、结晶性、表面缺陷对PSCs性能的影响机制，研究TiO2多孔膜纳米结构对光生载流子分离、传输、复合等动力学过程以及PSCs性能的影响机制。

钙钛矿电池（PSCs）是当今光伏领域的研究前沿，柔性PSCs因质量轻、可弯曲等优点而备受关注。然而，柔性PSCs的发展依然面临诸多难题，其中就包括功能层的低温制备问题。本项目采用溶液法低温（< 150 ℃）制备了非晶态WOx薄膜，将其用作PSCs电子传输层（ETL）并对其进行了化学修饰。结果表明，TiOx修饰可以调控WOx薄膜费米能级并有助于减少其内部缺陷态，从而有效缓解了ETL与钙钛矿之间的能级失配及电荷复合问题，最后大幅提高了器件能量转换效率。另外，我们将非晶态ETL材料用于制备柔性PSCs。结果表明，NbOx修饰可以增加WOx薄膜的导电性、透光率和载流子浓度，同时减小界面耗尽层厚度和薄膜表面陷阱态密度。基于NbOx-TiOx复合ETL构筑的平面异质结柔性PSCs能量转换效率达到了15.65%。我们通过对溶胶-凝胶法加以改进，成功在低温下（< 80 ℃）制备出了SnO2纳米晶，基于该材料组装的钙钛矿电池具有较高的光电转换效率，刚性器件和柔性器件分别达到了19.2%和16.1%。另外，我们还对介观钙钛矿电池的ETL结构进行了优化，基于非连续SnO2层制备了一种具有界面混合相的ETL，大幅减小了电池内阻，提升了器件效率并改善了稳定性。此外，我们还围绕PSCs进行了其它方面的研究，如调控钙钛矿层的结晶性、开发新型空穴传输材料等。本项目现已顺利完成，申请人以第一或通讯作何共计发表SCI论文13篇，授权专利2项，多次参加国际/国内学术会议并做邀请报告。