【作者】 杨祚宝；

【导师】 马忠权；

【作者基本信息】 上海大学 ， 凝聚态物理， 2013， 博士

【摘要】 阳极氧化法制备的TiO₂纳米管阵列，具有较大的比表面积和优异的一维特性，因此，被广泛应用于多种敏化太阳电池中。然而，目前基于TiO₂纳米管的敏化太阳电池普遍存在光电转换效率低、电子传输性能差以及敏化剂昂贵等问题。本论文以提高光电转换效率和降低成本为目标，在TiO₂纳米管光阳极的结构修饰、改性以及光电器件应用等方面进行了系统的研究和探索。具体研究内容如下：在工艺方面，研究了电解液成分、阳极氧化时间以及氧化次数等可变参数对TiO₂纳米管形貌及结构的影响。利用优化的工艺条件，制备了TiO₂纳米管阵列，纳米管长度均一、残留碎片较少，呈高度有序垂直的管状结构。以优化的TiO₂纳米管阵列为光阳极，与优化前相比，其染料敏化太阳电池的光电转换效率提高了36%左右。开发了一种以双表面活性剂为模板，在TiO₂纳米管表面均匀组装TiO₂颗粒来制备复合光阳极的简单方法。利用这种表面活性剂辅助真空培育的方法（Surfactant-assisted Vacuum impregnation，SVI），既能在TiO₂纳米管内、外壁有效填充TiO₂纳米颗粒，又可以避免TiO₂纳米颗粒的团聚而堵塞TiO₂纳米管，从而有效提高光阳极的比表面积。实验结果表明，经过SVI处理，可以大大提高TiO₂纳米管基染料敏化太阳电池的光电转换效率，通过调节填充比例，其光电转换效率提高到原来的1.94倍。通过精细控制阳极氧化工艺以及晶化处理方法，成功地制备了【001】择优取向的TiO₂纳米管阵列。实验结果表明，这种【001】择优取向的TiO₂纳米管在电子传输方面显示出优异的性能。通过简单的化学方法，将TiO₂纳米管从钛片成功剥离，并将其转移至FTO玻璃上，制备了前照明染料敏化太阳电池。与普通TiO₂纳米管相比，【001】择优取向的TiO₂纳米管基染料敏化太阳电池的光电转换效率提高了29%左右。采用微波辅助法，合成了粒径大小分别为3.1nm、4.3nm以及17.0nm的Cu₂ZnSnS₄（CZTS）量子点。综合利用XRD、Raman、HRTEM及XPS等系统表征，确定了合成的纳米材料为Kesterite结构的CZTS量子点。此外，UV-Vis吸收光谱中，CZTS量子点的吸收蓝移的现象，证实了粒径为3.1nm的CZTS量子点具有量子限域效应。以合成的CZTS量子点为敏化剂，制备了CZTS/TiO₂纳米管阵列太阳电池，实验结果表明，这种量子点敏化太阳电池具有良好的光伏效应，且其短路电流密度将随CZTS量子点尺寸减小而增大。同时，我们也探讨了CZTS量子点分别用于敏化TiO₂纳米颗粒和TiO₂纳米管时，其器件在光电性能、电子传输等方面的区别。在此，我们预测这种环境友好型的低成本CZTS/TiO₂纳米管阵列结构，在新一代量子点敏化太阳电池中将有广阔的应用前景。更多还原

【Abstract】 TiO₂nanotube arrays, which were prepared with anodization, were widelyused as photo-anode of dye-and quantum-dot-sensitized solar cells due to theirhigh specific surface area and excellent one-dimensional properties. However,low power conversion efficiency, poor electron transport and expensivesensitizer are still the issues for the TiO₂nanotube-based solar cells. In this work,aiming to improve the power conversion efficiency and lower the cost of theTiO₂nanotube-based solar cells, we investigated the decoration andmodification of photo-anode based on TiO₂nanotube arrays systematically.The details are as below.The influence of the composition of electrolyte, anodic duration and timeson the morphology and structure of TiO₂nanotube arrays have been investigated.The highly ordered TiO₂nanotube arrays with smoother surface and free debriswere obtained with a second-anodization under optimization. Compared withthat of the TiO₂nanotube arrays before optimization, the power conversionefficiency exhibits an enhancement of36%.We report for the first time a simple surfactant-assisted vacuumimpregnation （SVI） approach for controlling assembly of sub-10-nm TiO₂NCsinto NTAs as a more efficient photoanode for DSSCs. Double polymersurfactants were introduced to guide the NC assembly process and prohibit theNCs from over-agglomeration. Through the double-layer isolation by thelong-chain organic molecules, we are capable of achieving well-dispersed NCdeposition on the nanotube walls. The performance of DSSCs was greatimproved with the filled TiO₂nanotube arrays compared with that of un-filledone. By adjusting the content of filled nanoparticles, the power conversionefficiency was1.94times to that of the bare one. Highly [001] oriented TiO₂nanotube arrays were successfully prepared bycontrolling the recipe of anodization and process of post-treatment deliberately.The results reveal it shows excellent electron transport compare to non-orientedTiO₂nanotube arrays. It were detached and transferred to FTO successfully andunder front-illuminate, the enhancement of29%in power conversion efficiencywas obtained compared with non-oriented TiO₂nanotube arrays.Novel Cu₂ZnSnS₄（CZTS） quantum dots vary from3.1nm to17nm wereprepared with microwave-assisted route. The results of XRD, Raman, HRTEMand XPS show that it was the Kesterite CZTS quantum dot. The quantumconfinement effect was observed for CZTS quantum dots of3.1nm. CZTSquantum dots were used as sensitizer of TiO₂nanotube-solar cells and it showthat the short-circuit current density of the CZTS quantum-dot-sensitized solarcells increase with the decrease of diameter of quantum dots. Moreover, thedifference of J-V performance and electron transportation between TiO₂nanoparticle-and TiO₂nanotube-based solar cells sensitized with CZTSquantum dots were discussed. The prototype of the environmental friendlylow-cost CZTS quantum dot-sensitized solar cells was a promising structure inthe next-generation solar cells.更多还原