基于新型光阳极的构建和界面结构的调控提高太阳能电池性能的研究

Because of the outstanding photoelectric property, Ag2S have attracted much attention on the application of solar cells. However, there remain some structural flaws such as insufficient light absorption, excessive interface defects and unmatched energy level alignment which limited the performance of the solar cells. In the present research, we design a novel photoanode with a structure of Ag nanosheets (NSs)/Ag2S nanofilm (NF)/Ag2S quantum dots (QDs). The solar cells with this photoanode are expected to get a enhanced performance because the following advantages: Firstly, the Ag NSs supplies a direct route transport and collection of carriers; Secondly, the Ag NSs/Ag2S NF heterojunction prepared via in situ sulfide reaction offer a large exciton separation interface; Thirdly, the deposited Ag2S QDs extend the light absorption; Fourthly, the light modulation function of Ag NSs further increase the light absorption of the device. In this proposal, we will investigate on a graded heterojunction interface by annealing, try to obtain a better energy level matching and potential distribution, and accelerate the exciton separation and carriers transport. We will focus on the research of materials structure and energy band alignment of the Ag NSs/Ag2S NF interface. And then improve the photoelectric properties of photoanode on the basis of structure optimization. Through this research, we are expecting to master the key technology of producing the graded heterojunction interface, clarify the mechanism of exciton generation, separation and carriers transport, collection characteristics, and finally achieve an excellent photovoltaic performance of the solar cells.

硫化银是性能优异的光电材料，在太阳能电池方面有广阔的应用前景。然而，目前的硫化银太阳能电池在结构上还存在光吸收不足、界面缺陷过多及能级不匹配等问题，电池性能仍有很大提升空间。本项目设计了一种新型的光阳极结构：银纳米片阵列/硫化银薄膜壳层/硫化银量子点。这种光阳极结构兼具良好的电子传输通道，扩大的激子分离界面及优异的光吸收能力，应用于太阳能电池中，有望得到高的光电转换效率。本项目以实现合理的能级匹配及电势分布，促进激子分离及传输为目标，设计并可控制备具有成分梯度的渐变型银/硫化银异质结界面；重点研究银/硫化银异质结的界面物质结构和能级结构，在此基础上优化光阳极结构，提高光阳极的光电性能。通过本项目的研究，掌握渐变型银/硫化银异质结的制备工艺，阐明光阳极中激子产生、分离、载流子传输、收集的机理，并充分发挥这种光阳极结构的优势，获得具有优异性能的太阳能电池。

硫化银是性能优异的光电材料，在太阳能电池方面有广阔的应用前景。本项目致力于研究新型太阳能电池光阳极材料，以银/硫化银异质结纳米材料为研究对象，构造银/硫化银纳米片阵列结构，银/硫化银纳米树枝晶结构及氧化锌纳米棒/银/硫化银纳米颗粒结构，研究了其在有机无机杂化太阳能电池及量子点敏化太阳能电池中的应用。重点研究了异质结晶体结构、界面结构、核/壳尺寸对材料光电转化性能的影响，探究了光吸收、激子产生、传输、分离、载流子输运、收集的物理过程。设计材料体系，通过光催化性能研究，分析界面能级结构及载流子传输方式；通过表面增强拉曼光谱设计，提出银骨架的表面等离子共振增强光吸收的材料设计思路；研究了银直接作为电极材料的导电性能；研究了表面缺陷对材料中载流子捕获中心的影响，及材料作为光阳极时对载流子传输的影响。通过以上研究，得到了兼具良好的电子传输通道，扩大的激子分离界面及优异的光吸收能力的光阳极结构，解决了硫化银太阳能电池在结构上存在的光吸收不足、界面缺陷过多及能级不匹配等问题，充分发挥这种光阳极结构的优势，获得短路电流达到20.01mA/cm2，光电转化效率达到6.0%的太阳能电池。.