宽谱带吸收染料敏化上转换器@钙钛矿晶体核壳吸光体的设计制备及光伏器件研究

Accurately controlling intrinsic microstructure of absorber and heterojunction interface within photonic active layer on a molecular scale is a key technology to enhance photo-to-electron conversion efficiency of organic-inorganic hybrid solar cell (HSC). This project is to report a kind of novel method and design concept to construct a multi-functional photonic active film, that is, core-shell structured dye-sensitized upconverter@CH3NH3PbI3-xClx absorber with broadband absorption and excellent conductivity is sequentially deposited on ZnO compact layer, and then filled in nanoscale with polymer to form ZnO/core-shell structured absorber/polymer planar heterojunction film. As a consequence, multi-objectives including high ultilization of broad solar spectrum, efficient charge carrier seperation, transport and collection will be simultaneously achieved. By means of optimizing preparation procedures, the core size, shell thickness, composition, morphology, structure, surface of absorber, as well as thickness, interface and evenness of thin film will be controllably obtained. Especially, the broadband absorbed UCPs will also be obtained by adjusting dye co-sensitization. The effect of microstructures, features, performances of core-shell structured absorber on light absorption utilization and electron transfer process will be investigated.This study will reveal the relation and mechanism among the microscosmic heterjunction interface, charge carrier seperation and transport, and photovoltaic performance within photonic active layer. The implementation of this project will further provide solid fundamental basis and practice guide for the industrialization of perovskite-based HSC in the future.

在分子水平上精细调控吸光体的本征微结构和异质结界面是提高HSC光电转换效率的关键技术。本项目拟运用一类全新的方法和设计理念来构筑多功能光活层，即在ZnO致密层上通过连续沉积法制备染料敏化UCPs@CH3NH3PbI3-xClx核壳吸光体，基此构建高效ZnO/核壳吸光体/聚合物平面异质结薄膜，以期同步实现太阳光广谱采集利用、光生载流子有效分离和收集的目的。同时通过优配条件精细调控核壳吸光体的核尺寸、壳厚度、组成、结构、形貌、表面以及薄膜厚度、界面和均匀度。特别是通过调控不同光响应范围的染料共敏获得宽光谱吸收的UCPs。探索研究核壳吸光体微结构、特性、功能对光吸收利用和载流子转移历程的影响规律，揭示光活层复杂的微观异质结界面-电荷分离与传输-光伏性能之间的相互依存关系和作用机制，为钙钛矿基HSC在未来太阳能薄膜电池产业中的应用提供理论基础和实践指导。

本项目以构筑多功能ZnO/钙钛矿吸光体/Spiro-OMeTAD光活层为目的，设计制备宽光谱吸收的染料敏化上转化纳米颗粒（IR806-UCNCs）@钙钛矿核壳吸光体和具有良好电子传输性能的ZnO纳晶膜，基此构建高效的钙钛矿太阳能电池（PSC），具体研究结果有：.1.ZnO 纳晶膜：采用溶液法制备ZnO纳晶薄膜，探究了ZnO微结构包括形貌、组分、结晶相组成及能级分布等的变化规律与调控机制。所制备的致密平整、兼具较低功函数和电子传输优势的ZnO纳晶膜，与钙钛矿层的能级更匹配，有助于光生电子的抽取和收集。.2. 宽光谱响应的钙钛矿光活层：制备 β-NaYF4:Yb,Er UCNCs和IR806-UCNCs，采用配体交换法于ZnO纳晶膜上原位生长宽光谱响应的UCNCs@钙钛矿核壳吸光体和IR806-UCNCs@钙钛矿核壳吸光体。利用各种显微表征技术和光谱测试手段，探究了UCNCs、IR806-UCNCs对钙钛矿晶体生长及薄膜形貌、光吸收能力、电荷输运等的调控机制。结果表明，1）UCNCs、IR806-UCNCs 作为成核位点，钙钛矿异质外延生长形成结晶度高的核壳大晶粒，大大减少了钙钛矿薄膜的缺陷，降低了电子-空穴复合几率；2）钙钛矿壳层包覆减少了IR806-UCNCs的表面缺陷，改善其导电性，提高了载流子的传输，改善了IR806-UCNCs与钙钛矿之间的能量传输；3）IR806作为天线可有效吸收750-850 nm的可见-近红外光并通过红外共振能量转移的方式将能量转移至UCNCs，发射出钙钛矿吸光体可吸收的上转换可见光，实现了钙钛矿薄膜的宽带近红外（800-1000nm）吸收利用。.3. 高效PSC器件：制备高性能ZnO（电子传输层）/核壳吸光体/Spiro-OMeTAD（空穴传输层）异质结薄膜，优化光活性层的界面、组分和电池制备工艺，构建多种高效稳定的PSC。光电测试表明，维度和组分调控，界面修饰，电池结构及工艺的优化可大大促进光生电荷的分离、传输，同时减少电荷复合，有助于提高PSC的光电转化效率（超过20%）和稳定性。.本项目研究成果目前已发表SCI论文15篇。申请专利5项，授权2项。参加国际会议5次，国内会议4次。培养博士生6名（毕业2名），硕士生17名（毕业9名）。