有机铅卤钙钛矿微观结构与光伏性能关联研究

Though perovskite solar cells have attracted numerous attention in recent years, the fundamental mechanism determining their high power conversion efficiency, and the heterogeneity in photovoltaic properties at micro-level remain unclear, requiring in-depth investigation. This proposal focuses on perovskite thin films and photovoltaic devices, aimed to retrieve the relationship between microstructure and photovoltaic performance. Grazing-Incidence X-ray diffraction (GIXD) and photoemission electron microscopy (PEEM) will be employed to unveil details of morphology and crystal structure. The formation mechanism of perovskite microstructures will be studied by manipulating the dynamics of nucleation and growth. The scanning probe microscopy, e.g. Kelvin probe force microscope (KPFM) and conductive atomic force microscopy (c-AFM), will be utilized to figure out the correlation between microstructure and local photovoltaic performance. Spatially dependent carrier dynamics will be studied using photo-induced absorption and emission. Profound understanding of the structure-property relationship will be obtained by constructing real working devices, to promote devices with higher efficiency and greater stability.

钙钛矿型太阳能电池近年来广受重视，但决定其高转换效率的物理机制，及其在微纳尺度下呈现的光伏特性各向异性等基础性问题仍没有统一的认知，亟待深入的研究和探讨。本项目以钙钛矿型薄膜材料和器件为研究对象，探讨微观结构对局域电学和光学性质的影响，构建微观结构与宏观光电性能的关联。研究拟采用掠入射X射线散射（GIXD）和光发射电子显微镜（PEEM）等技术手段对钙钛矿薄膜微纳结构进行定量分析，获取钙钛矿材料形貌细节和晶体结构参数；通过改变薄膜制备条件，控制材料的结晶与成核过程，探究微观结构形成的物理机制；通过开尔文探针力显微镜（KPFM）和导电原子力显微镜（c-AFM）等扫描探测显微技术，获取微观结构与局域光伏性能的关联；通过超快光学手段（光致发光、光致吸收等）探究微观结构对三维载流子动力学的影响；构建光伏器件，深入理解材料与器件的构效关系，进一步指导制备高效率、高稳定性的器件。

有机无机杂化钙钛矿因其具有光电转换效率高，制备成本低廉，制备工艺简单等优势受到研究人员的广泛重视。钙钛矿是一种多晶材料，表面性质呈现不均一性，其局域微纳性质与材料的光电属性具有直接关联，但受限于所采用的研究方法和手段，研究人员并未明确报道这种关联性质。利用本基金的资助，我们以钙钛矿薄膜材料和器件为对象，利用薄膜非平衡生长和界面工程技术，并合理运用时间分辨、空间分辨及能量分辨等多种技术手段，从表面形貌、晶体结构、载流子动力学等方面探讨微观结构对局域性质的影响，构建微观结构与宏观光电性质的关联。研究内容包括钙钛矿结晶生长机制，界面电荷传输机制及电荷传输层的作用机制。进而基于相关认知，通过调控薄膜形貌和结构，改善钙钛矿和界面传输层的电荷传输特性，进而提升钙钛矿太阳能电池的光电转换效率和稳定性。本项目为深入理解器件工作机理，通过调控薄膜形貌和器件结构提升器件性能提供了非常有益的参考。