CdS量子点敏化ZnO/ZnS纳米结构太阳能电池的研究

	CdS量子点敏化ZnO/ZnS纳米结构太阳能电池的研究
	孙云飞
学位类型	博士
导师	杨景海
	2014-07
学位授予单位	中国科学院大学
学位专业	凝聚态物理
摘要	能源危机已成为人类面临的主要难题之一。人类目前所利用的能源主要是石油、天然气和煤炭等化石能源。这几种能源的储量在逐年减小，而且价格不断攀升。能量的短缺严重地抑制了未来社会的发展。开发新能源和可再生清洁能源在世界经济发展中具有重要作用。充分开发利用太阳能是世界各国政府可持续发展的能源战略决策。太阳能资源取之不尽、用之不竭，因此将太阳能转化成电能和热能为人类服务一直是科学家追求的目标。在太阳能利用中，太阳能发电最受瞩目。太阳能电池具有很多优点，比如：安全可靠，无噪声，无污染，能量随处可得等等。量子点敏化太阳能电池在第三代太阳能电池中占有重要地位。理论的研究结果表明量子点材料由于具备可调的吸收波段、多重激子效应和双光子激发效应，可以获得高达66％的光电转换效率。因此量子点敏化太阳能电池受到科研工作者的广泛关注。本论文将ZnO做为光电阳极材料，镀有Pt的ITO作为对电极，中间充满碘电解质来制作太阳能电池。首次研究了ZnS和ZnS:Mn2+纳米粒子作为致密层对电子传输的影响。而且研究了量子点和染料共敏化在改进太阳能电池效率方面的作用。主要内容如下： 1. 通过水热法成功生长了ZnO纳米钉和纳米棒，PL和变温PL同时揭示了ZnO纳米钉中具有更少的非辐射复合，使得ZnO纳米钉的紫外发光强度与可见发光强度的比是ZnO纳米棒的2.3倍。该研究将会激发更多关于ZnO纳米钉的研究，并为其在激光器、气体传感器和发光器件方面的应用研究奠定一定理论基础。 2. 在ZnO纳米棒的表面覆盖一层ZnS，以ZnO/ZnS的复合结构做为光电阳极，制作量子点敏化太阳能电池。研究了不同方法制备的ZnS致密层对太阳能电池的性能影响。与旋涂方法制备的ZnS层相比，通过连续离子层沉积方法制备的ZnS层能更有效地阻碍电子的反方向传输，抑制电子和空穴的复合，从而有效提高太阳能电池的开路电压。 3. 为提高ZnO/ZnS/CdS电池能级匹配程度，用ZnS:Mn2+纳米颗粒替代ZnS作为致密层，制作太阳能电池。采用旋涂法将ZnS:Mn2+纳米颗粒沉积在ZnO纳米棒的表面。结果表明随着锰掺杂浓度的提高，ZnS:Mn2+ 的导带底下移，有利于电子向ZnO纳米棒的传输，从而使得量子点敏化太阳能电池的效率增大。 4. 通过连续离子层沉积的方法在ZnO纳米棒上生长一层ZnS层，并以ZnO/ZnS为光电阳极制备量子点敏化和CdS/N719共敏化太阳能电池。当CdS的沉积次数为12次时，量子点单敏化的太阳能电池的效率达到最佳。以此结构为基础，又研究了量子点/有机染料共敏化太阳能电池，研究发现，当染料的沉积时间为17h时，共敏化太阳能电池的效率比单敏化太阳能电池的效率提高了37%。
其他摘要	The energy crisis has become one of the main challenges that human faced. Energy sources that can be used by human are fossil energy such as oil，gas and coal. These energy reserves decrease year by year and the price is rising.The shortage of energy seriously inhibits the development of the society in the future. The development of new energy and renewable clean energy plays an important role in the world economic development. Development and utilization of solar energy is the energy strategy for the sustainable development of the world's governments. Solar energy resources are inexhaustible, therefore, the conversion from the solar energy into electricity and heat energy for the human service has been always the goal of scientists. In solar energy, solar power is the most notable. The solar cell has many advantages such as safe and reliable, noiseless, non-pollution, widely available and so on. Quantum dots sensitized solar cell occupies an important position in the third generation solar cells. The theoretical research results show that quantum dots have tunable absorption band, multiple exciton effect and the two-photon excitation effect so that up to 66% of the photoelectric conversion efficiency can be obtained. Therefore quantum dots sensitized solar cell received widespread attention from research workers. In this thesis, ZnO was used as photoanode materials and bonded with a platinum-coated ITO) (20nm thick) counter electrodes to assemble QDSSCs. A mixture of 0.5M LiI and 0.05M I2 aqueous solution was used as electrolyte. ZnS and ZnS:Mn2+ nanoparticles as compact layer were investigated for the first time to assess their effects on the charge transport. And the function of cosensitization with quantum dots and organic dye on the improvement of conversion efficiency of solar cells was investigated. Main contents are as follows: 1. We successfully synthesized ZnO nails and ZnO rods by a simple hydrothermal method. Both time-resolved PL and temperature-dependent PL spectra reveal a less nonradiative contribution in ZnO nails, which induces that the relative emission intensity ratio between UV and deep level emission in room-temperature PL spectra for nails is 2.3 times higher than that of rods. Our results will stimulate more investigation on ZnO nails and finally pave a way for ZnO nails in the application of laser, gas sensors, and light emitting devices. 2. The ZnS NPs layers were deposited on ZnO NRs and ZnO/ZnS composite nanostructure was used as photoanode to fabricate QDSSCs. The effects of ZnS on the properties of QDSSCs were discussed. When ZnS NPs layer was spin coated on ZnO NRs, the performance of QDSSC did not change a lot due to the aggregation of ZnS NPs. However, when ZnS NPs layer was formed by (Successive ionic layer adsorption and reaction)SILAR method, it can inhibit the opposite direction transfer of electrons and recombination of electro-hole pairs more efficiently. The open-circuit voltage of QDSSCs was improved obviously. 3. To further improve the energy alignment of ZnO/ZnS/CdS solar cells. The CdS quantum dots sensitized ZnO nanorods solar cells with ZnS:Mn2+ nanoparticles as compact layer were fabricated. The ZnS:Mn2+ nanoparticles were deposited on the surface of ZnO nanorods by spin coating. The results indicated that with the increase of Mn2+ doping concentration, the energy level of conduction band of ZnS:Mn2+ nanoparticles turned lower, which is beneficial for the charge transfer from the conduction band of CdS, resulting in an enhancement of conversion efficiency of solar cells. 4. The ZnO/ZnS core–shell hierarchical structure prepared by SILAR method as photoanode was used in the QDSSCs with N719/QDs cosensitizing. The QDSSC based on ZnO/ZnS/CdS(12)architecture exhibited a maximum power conversion efficiency of 1.16% due to the better light harvesting. Depositing a thin layer of N719 dye onto the ZnO/ZnS/CdS(12) structure can further improve the photovoltaic performance of the solar cells. When ZnO/ZnS/CdS(12) electrode is sensitized with N719 for 17 h, the device shows a 37% enhancement in energy conversion efficiency compared with the device only sensitized with CdS QDs.
语种	中文
文献类型	学位论文
条目标识符	http://ir.ciomp.ac.cn/handle/181722/41470
专题	中科院长春光机所知识产出
推荐引用方式 GB/T 7714	孙云飞. CdS量子点敏化ZnO/ZnS纳米结构太阳能电池的研究[D]. 中国科学院大学,2014.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
孙云飞.pdf（4286KB）			开放获取	CC BY-NC-SA	请求全文