核壳Au@量子点共敏化光阳极及其界面电荷传输机理研究

The less light harvesting as well as charge injection and transport efficiency still exit within the interface of the photoanode, which have become the problems remained to be solved in the application fields of quantum dot sensitized solar cells (QDSC). According to the literature and our previous work, noble metal Au nanoparticles may increase the photo-energy conversion efficiency of photoanode by (1) increasing the efficiency of charge carrier separation and (2) extending light harvesting and facilitating the generation of photoinduced charge induced by the surface plasmon resonance effect. This proposal aims at developing a novel broad-spectrum responded core-shell Au@quantum dot synergistic sensitized photoanode. Various microscopic characterization techniques, spectral analysis, simulation calculation and photoelectric testing will be used to study the light harvesting, charge transport and photon-to-current conversion efficiency depend on the core/shell structure. The as-prepared anode will be assembled into devices to further investigate the effect of micro/nanostructure of core/shell structure surface/interface on photogenerated charge transport. We will give a systematic study to reveal the electron lifetime and microscopic process and intrinsic mechanism of electron transport in TiO2/Au/quantum dots/electrolyte. We will further study the synergistic sensitization mechanism and regularity of Au nanoparticles and semiconductor quantum dots (CdS/CdSe). This project is an important driving force for the development of more efficient QDSC and it will provide the theoretical foundation and experimental support for exploring novel methods and new materials for further improving the efficiency of solar devices.

量子点敏化太阳能电池（QDSC）的光阳极存在光利用率低及界面电荷易复合等科学问题，限制了QDSC效率的进一步提高。文献和我们前期工作表明：Au纳米颗粒修饰光阳极具有显著的等离子增强作用，通过结构与界面调控有望实现宽光谱响应，同时极大的提高电荷传输效率。本项目拟设计并构建全新的宽光谱响应的核壳Au@半导体量子点协同敏化的光阳极。采用各种显微表征技术、光谱分析、模拟计算及光电测试手段，探究核壳结构的调控对整个光阳极的光吸收、电子传输以及光电转化效率的影响。系统研究核壳结构的表/界面微纳结构对光生电荷传输影响，分析电子寿命及其在不同界面之间传输的微观过程和内在机理，揭示Au颗粒与半导体量子点的协同敏化机制，最终获得更高效的QDSC。本项目的开展为探索高效太阳能器件的新途径和新材料提供理论基础和实验依据。

量子点敏化太阳能电池（QDSC）的光阳极存在光利用率低及界面电荷易复合等科学问题，限制了QDSC效率的进一步提高。本项目针对QDSC关键材料—半导体光阳极的组分和结构进行设计和制备。首先将Au纳米颗粒组装到光阳极薄膜中并与量子点构成核壳结构，实现了光阳极的光吸收及电荷传输性能同步提升，使得器件的短路电流密度大幅提高，最终电池的光电转化效率提高了50%。此外，通过将三维氧化锌纳米花、核壳Au@SiO2可控的组装到TiO2光阳极或对TiO2光阳极进行钛醇盐后处理过程等策略构建了多种高效的复合光阳极，发展了不同的复合光阳极薄膜组装技术，分别探究了不同的方法对电池的光电转换特性、电子传输特性、光谱特性的影响机制，获得高效的电池光电转换效率。该项目的实施为太阳能电池光电极的研究提供了理论借鉴和实验依据，也为发展高效的太阳能电池器件提供切实可行的新材料体系和新方法。