【作者】 宋鑫；

【导师】 孙景； 杜希文；

【作者基本信息】 天津大学 ， 材料学， 2010， 博士

【摘要】 太阳能的开发利用对解决能源危机和发展低碳经济都具有极其重要的意义。其中,新一代太阳能电池——量子点敏化太阳能电池由于具备高理论转换效率和低生产成本,引起了科学界的广泛关注。但迄今为止,量子点敏化太阳能电池的光电转换效率仍然远低于传统太阳能电池。本文从材料角度出发,考虑材料本身缺陷、能级匹配及制备工艺对太阳能电池性能的影响,设计了硫化镉(CdS)和氧化锌(ZnO)纳米异质结构作为光电转换材料,采用化学浴沉积和水热法合成技术,可控合成了硫化镉量子点及氧化锌纳米线阵列,并确定了最优工艺参数。通过研究退火处理对CdS/ZnO量子点敏化太阳能电池转换效率的影响,我们发现退火温度和CdS量子点的层数对最终太阳能电池的性能有决定性的影响。经过退火处理后的太阳能电池的光电转换效率有了显著提升,可以归因于材料对太阳光吸收能力的增强、本身缺陷的减少以及CdS/ZnO之间扩散层的形成。通过化学浴沉积和退火处理的结合使用,在ZnO表面获得了两种不同粒径的CdS量子点。两种CdS颗粒形成I型半导体后产生的共敏化作用使得电池性能有显著的提升。此研究证实,量子点的合理搭配可以有效提升量子点敏化太阳能电池的性能。通过水热反应,制备了由CdS量子点堆积而成的三维多孔薄膜。利用此多孔薄膜作电池光阳极材料可以形成自敏化太阳能电池并实现光电有效转换。采用电沉积技术,可以在CdS多孔膜上沉积CdSe量子点,并形成由CdSe/CdS组成的共自敏化结构,使太阳能电池的性能得到进一步提升。更多还原

【Abstract】 The development of high-performance solar cell is of great significance in solving the energy crisis and development of low-carbon economy. Quantum dot-sensitized solar cell (QDSSC), a third generation solar cell with higher theoretic power conversion efficiency (PCE) and lower cost, have attracted the attention of many scientists in the solar cell area. So far, however, the PCE of QDSSC is still much lower than that of the traditional solar cells.In this thesis, considering that the synthetic processing, existance of defects in materials, configuration of energy levels can greatly influence the PCE of QDSSC, wedesigned a CdS/ZnO heteronanostructure as anode material, adopted chemical bath deposition and hydrothermal technique as synthetic methods, and controllaby synthesized the CdS quantum dots (QDs) and ZnO nanowires (NWs) arrays.We investigated the effect of annealing treatment on the PEC of the CdS QDSSC. The thickness of CdS layer and the annealing temperature were found to be very crucial for the performance of CdS/ZnO solar cells. The PCE was improved significantly after annealing treatment, which could be attributed to the enhancement of the absorption ability, decreasing the defects of anode materials and the formation of a diffusion layer between the CdS shell and ZnO core.Dual-sized CdS quantum dots were employed as light harvesters to achieve high PCE. Chemical bath deposition and annealing treatment were adopted to produce CdS quantum dots with different sizes. The strategy of co-sensitization by dual-sized CdS quantum dots could significantly improve the performance of solar cells by forming a type-I band structure. This work indicates that the proper configuration of quantum dots is crucial on the photovoltaic conversion of solar cells.We developed a self-sensitized solar cell with CdS porous structure as the anode material. The CdS porous structure, assembed by high-density CdS nanocrystals, was synthesized by hydrothermal method and could effectively realize the photovoltaic conversion. The CdSe/CdS co-sensitized structure, another self-sensitized system with CdSe nanoparticles on the CdS porous structure, was obtained via electric deposition, which further, improved the performance of the solar cell.更多还原