【作者】 王仁宝；

【导师】 徐进章；

【作者基本信息】 合肥工业大学 ， 电气工程， 2014， 博士

【摘要】 无机半导体量子点和半导体薄膜是量子点敏化太阳电池(QDSSCs)重要组成部分,直接影响其光伏性能。本文从探索量子点制备的新方法、改变半导体薄膜性质以及量子点在半导体薄膜上的组装方式等方面展开实验研究,以期改善QDSSCs的光伏性能。本文通过在TiO2中掺入SiO2获得纳米TiO2-SiO2复合薄膜,并应用于QDSSCs。SiO2的掺入既可有效调控纳米TiO2薄膜比表面积、孔容和孔径,增加量子点的吸附量,又可形成SiO2阻挡层能有效抑制电池中电荷复合,提高光电流。利用胶状CdSe量子点敏化TiO2-SiO2复合薄膜制备光阳极,并组装太阳电池。通过交换CdSe量子点表面配体,CdSe量子点可更好地吸附到TiO2-SiO2薄膜里,促进光生电子传输,减少电荷复合机率,提高光电子转换效率。实验结果表明,掺入SiO2和配体交换能改善QDSSCs的光伏性能,MPA包覆的CdSe量子点敏化TiO2-SiO2光阳极制备的太阳电池效率达到1.74%。本文探索一种新的气—热液(hot-bubbling)方法制备CdSe量子点,从反应时间、Cd:Se浓度比和反应温度三个方面探讨hot-bubbling方法合成的CdSe量子点性能。实验结果表明,该方法能合成光学性能良好、尺寸较均匀和分散性好的闪锌矿型CdSe量子点。本文利用hot-bubbling方法合成的CdSe量子点敏化TiO2-SiO2复合薄膜,制备太阳电池,探讨其对QDSSCs光伏性能的影响。实验结果表明,太阳电池的光电转化效率达到1.94%,高于经典的热—液注射法(hot-injection)制备CdSe量子点敏化太阳电池效率,完全可与其相媲美,能作为新的量子点制备方法推广使用。在量子点组装方式上,结合连续离子层吸附(SILAR)技术和自组装单层膜(SAM)技术的各自优点,CdS和CdSe分别采用SILAR法和SAM法组装方式,获得CdS/CdSe量子点共敏化TiO2-SiO2光阳极,并组装电池,组装过程采用水代替有机试剂做溶剂,实现绿色组装路线。新的组装方式既实现高效地利用TiO2-SiO2复合薄膜的微孔和介孔,增加量子点的吸附量,并降低多层沉积带来的层与层之间产生的缺陷态,又实现很好地控制量子点的尺寸,同时,可有效抑制光电子与电解质的复合。详细讨论CdS沉积工艺与CdSe共敏化对TiO2-SiO2/CdS/CdSe光阳极光学性能及其组装电池光伏性能的影响,确定CdS沉积次数和CdSe的最优组合,从微观层面解释该组装方式对太阳电池性能的影响。对其它种类和组合的量子点敏化剂研究有着一定借鉴意义。更多还原

【Abstract】 Inorganic Semiconductor Quantum Dots (QDs) and porous film are two important parts of quantum dots sensitized solar cell (QDSSCs). And they play decisive roles in the performance of solar cells. In order to improve the performance, three aspects that are the property of porous film, the new method of preparing QDs and the assembly way of QDs in the porous film are studies in this paper.TiO2-SiO2composite films are prepared through a simple process, and applied in quantum dot sensitized solar cell in this paper. The surface area, pore volume, and aperture of TiO2film are controlled effectively duo to the incorporation of SiO2. Such the adsorption capacity of quantum dots is increased. SiO2forms barrier, which inhibits interface charge recombination. Then photocurrent is increased. Solar cells are assembled by the anode which is prepared using colloidal CdSe QDs sensitized TiO2-nano-SiO2composite films. CdSe QDs can be adsorbed onto the TiO2-SiO2film better through the exchange of ligand. Then the photogenerated electrons transfer can be promoted, the charge recombination can be reduced, and the efficiency of solar cell can be improved. The result shows that Solar cell which is assembled by the CdSe QDs sensitized TiO2-nano-SiO2photoanode has an efficiency of1.74%.A new gas-thermal liquid (hot-bubbling) method is explored to prepare CdSe QDs in the paper. Its effect on the photovoltaic properties of QDSSCs was investigated. The performance of CdSe QDs is studied by the reaction time, the Cd:Se concentration, and the reaction temperature. The result shows this method can synthesize zinc blende CdSe QDs with the uniform size and good dispersion under the proper reaction conditions.QDSSCs are assembled through the anodes which are sensitized by CdSe quantum dots prepared by the hot-bubbling method. The photovoltaic performance of QDSSCs is investigated. The experiment shows that the solar cell which is sensitized by CdSe quantum dots has an efficiency of1.94%. It can be used as a new preparation method to extend.The successive ionic layer adsorption and reaction (SILAR) and the self-assembled monolayer (SAM) methods are combined to obtain the CdS/CdSe co-sensitization TiO2-nano-SiO2composite films. Namely, CdS and CdSe QDs are assembled onto TiO2-nano-SiO2film by the SILAR and SAM respectively. Meanwhile, the assembling routes are green duo to using aqueous solvent in the whole process. The new assembly mode can achieve a high coverage of the TiO2-nano-SiO2surface, get a good control of the size distribution, and lower the defect state that has produced by the multilayer deposition. At the same time, the charge recombination between the photoelectron and electrolyte can be inhibited effectively. The effect on the properties of solar cells is discussed through CdS deposition process. The CdS optimal deposition cycles are determined. The effect is studied on a micro level. The assembly method offers a certain reference meaning to other types of quantum dots in the co-sensitized solar cells.更多还原