【作者】 张旭；

【导师】 薛怀国； 吴战宇；

【作者基本信息】 扬州大学 ， 工程硕士（专业学位）， 2021， 硕士

【摘要】 对太阳能的高效利用目前是平衡能源和环境问题的最优方案之一,目前的光电转换器件普遍存在材料昂贵,工艺复杂等问题,钙钛矿材料凭借其优异的光电性质和低廉的加工成本已经受到全世界科研工作者的青睐。短短十年,钙钛矿太阳能电池已经取得25.5%的光电转换效率,而钙钛矿量子点结合了钙钛矿块体材料和传统半导体量子点的性质,从而具有优异的光电性质,如较高的荧光量子产率、极窄的半峰宽、带隙可调、可见光内全光谱覆盖等,这些性质使得钙钛矿量子点成为目前最具有前景的光电材料之一,并广泛应用于发光二极管、太阳能电池、激光、光电探测器等领域,但是目前对钙钛矿量子点的研究主要集中在全无机材料,此外钙钛矿材料的发展严重受到稳定性的制约,因此本文主要从钙钛矿量子点的合成以及钙钦矿量子点的水稳性出发进行研究,为将来钙钛矿材料的商业化应用打下基础,本文的主要工作如下:(1)本章节我们从原料、表面配体、反应溶剂三个角度出发,对传统经典钙钛矿量子点的合成方法进行了改进并探索了该方法的大规模商业生产的可行性,通过原料的优化,我们制备了高质量的CsPbBr3和FAPbI3量子点;通过合成后处理方法对量子点的形貌进行调控,我们得到了完美的CsPbBr3纳米盘;我们通过正辛烷作为反应溶剂合成出均匀的FAPbI3纳米棒,进一步推动了钙钛矿量子点的基础研究。(2)在本章中,我们采用合成后配体交换的方法,制备了具有X型表面配体(全氟癸硫醇)的CsPbBr3量子点。凭借Pb-S化学键的稳定性以及配体分子之间的作用力,使得全氟癸硫醇小分子可以配位到量子点表面,引入量子点表面的氟分子层可以有效的增强材料的抗水稳定性,在我们的方法中小分子配体交换可以平衡材料的导电性和稳定性,此外这种方法处理后的量子点依旧维持良好的胶体性质,凭借溶液工艺可以大幅降低工艺成本,我们提出的合成后处理的方法将促进CsPbBr3量子点在光电器件的应用。(3)我们提出了一种简单有效的方法来抑制FA基量子点的卤素离子交换反应,同时增强材料的稳定性,胶体量子点在PbSO4-oleate分子团簇的辅助下整齐地嵌入PbSO4的壳中,这种自组装过程形成了一维量子点的超晶格的同时并在其表面上形成了 PbSO4层,这些无卤素的薄壳可作为屏障,有效地阻止离子迁移过程以及水分子对钙钛矿结构的破坏,利于混合卤素钙钛矿量子点其在光学器件中的应用。更多还原

【Abstract】 Efficient use of solar energy is currently one of the best solutions to balance energy and environmental problems.Current photoelectric conversion devices generally have problems such as expensive materials and complex processes.Because of these excellent photoelectric properties and low processing cost,perovskite materials have been vigorously explored by scientific researchers all over the world.In just ten years,perovskite solar cells have achieved a photoelectric conversion efficiency of 25.5%,and perovskite quantum dots combine the excellent photoelectric properties of perovskite materials with the properties of traditional semiconductor quantum dots,such as higher fluorescence quantum yields,PLQY,extremely narrow half-value width,adjustable band gap,full-spectrum coverage in visible light,etc.These have made perovskite quantum dots one of the most promising optoelectronic materials at present,and perovskite quantum dots are widely used in light-emitting diodes and solar cells,Lasers,photodetectors,etc.However,the current research on perovskite quantum dots is mainly focused on all-inorganic materials.In addition,the development of perovskite materials is severely restricted by poor stability.Therefore,this article mainly focuses on the synthesis of perovskite quantum dots and the improvement of perovskite quantum dots.Our research lays the foundation for the practical application of perovskite in the future.The main work of this paper is as follows:(1)In this chapter,we have improved the synthesis method of traditional classical perovskite quantum dots from the perspectives of raw materials,surface ligands,and reaction solvents.The morphology of CsPbBr3 nanodisks is adjusted through post-synthesis processing methods,and uniform FAPbI3 nanorods are synthesized using n-octane as the reaction solvent,which further promotes the basic research of perovskite quantum dots.(2)In this chapter,we used the method of ligand exchange after synthesis to prepare CsPbBr3 quantum dots with X-type ligands(C10H5F17S).With the stability of the Pb-S chemical bond and the force between the ligand molecules,small C10H5F17S molecules can be coordinated to the surface of the quantum dots.The introduction of the fluorine molecular layer on the surface of the quantum dots can effectively enhance the water stability of the material in our method,the small molecule ligand exchange can balance the conductivity and stability of the material.In addition,the quantum dots treated by this method still maintain good colloidal properties,and the solution process reduces the subsequent processing costs Our proposed synthetic post-processing The method will promote the application of CsPbBr3 quantum dots in optoelectronic devices(3)We propose a simple and effective method to inhibit the halogen ion exchange reaction of FA-based quantum dots,while enhancing the stability of the material to water.The colloidal quantum dots are neatly embedded in the PbSO4 shell with the aid of PbSO4-oleate molecular clusters.This self-assembly process forms a PbSO4 layer on the superlattice surface of the quantum dots.In the shell,this self-assembly process forms a PbSO4 layer on the superlattice surface of the quantum dot.These halogen-free thin shells can act as a barrier to effectively prevent the ion migration process and the destruction of the perovskite structure by water molecules.It is beneficial to the application of mixed halogen perovskite quantum dots in optical devices.更多还原