【作者】 刘一婷；

【导师】 刘爱民；

【作者基本信息】 大连理工大学 ， 微电子学与固体电子学， 2011， 博士

【摘要】 随着经济的快速发展,能源问题已经成为世界各国经济发展遇到的首要问题。占地球总能量99%以上的太阳能,由于具有安全、无污染；取之不尽、用之不竭的优点而受到科学家们的青睐。近年来,太阳能电池作为太阳能资源利用的重要途径之一,已经引起了学术界的极大关注,并且取得了很大的发展。一直以来,太阳能电池的研究工作主要集中在提高电池的光电转换效率和降低成本方面。有机小分子材料酞菁铜作为一种典型的P型材料,对600～700 nm的可见光具有较强的吸收,且其载流子的迁移率较高,因此常常被用作有机太阳能电池中的给体材料。目前,基于CuPc的有机太阳能电池的实验室效率最高可达5.58%,但依旧无法与无机硅太阳能电池相比。通过改进器件结构、加深对器件传输机制以及界面的理解,都将有助于电池效率的提高。本论文是针对具体基于酞菁铜的太阳能电池的研究,主要在以下三个方面进行了有益地探索：1.采用CuPc掺杂的MEH-PPV作为电子给体,PCBM作为电子受体,制备了三种不同CuPc掺杂比例的体异质结太阳能电池,研究了CuPc掺杂对MEH-PPV:PCBM混合薄膜光电特性的影响。结果表明,CuPc掺杂使MEH-PPV:PCBM混合薄膜的紫外—可见吸收光谱在可见光区域得到了一定的拓展,从而使电池活性层对入射光子的吸收能力得到了进一步地增强。混合薄膜的荧光光谱分析也显示了光生激子的拆分得到了有效地提高。进一步对电池的电流—电压特性进行了测试,验证了CuPc可以作为电子给体对MEH-PPV进行掺杂来改善电池的性能,并分析得出最佳光电性能时的质量比。2.采用有机小分子材料CuPc作为电子给体,与绒面n型Si一起组建有机/无机复合太阳能电池,并且讨论了硅表面织构处理对太阳能电池光伏性能提高的重要作用。此外,还应用电化学阻抗谱技术研究了该电池的阻抗特性,建立了一个可以完整地描述电池结构的等效电路,并且与阻抗的理论模型相结合,对电池的阻抗谱图进行了分析,从而确定了电池中载流子的传输机制为e指数陷阱分布的空间电荷限制电流。3.采用化学湿法沉积,在导电ITO基底上制备了ZnO纳米棒阵列薄膜,利用Kelvin探针测试系统定量测量了ZnO纳米棒阵列的表面光伏响应与弛豫过程,并通过对其弛豫过程的分析获得了ZnO纳米棒阵列薄膜能级结构的特性。此外,还利用Kelvin探针技术测试了CuPc薄膜的光电行为以及它对ZnO纳米棒阵列薄膜光电行为的影响。并结合基于锁相放大器的光伏测试技术,讨论了外来还原性分子乙醇对CuPc/ZnO纳米棒阵列复合体系光电响应的影响,得到了一些有价值的结果和经验,为今后制备CuPc/ZnO纳米棒阵列复合太阳能电池提供了直接的借鉴。更多还原

【Abstract】 With high-speed development of economy, energy problems have become the most vital obstacle to development all over the world. Solar energy that is over 99% of total energy on the earth, have gained a great deal of attention by scientists due to its many merits, such as safety, disbefouling environment, and extremely excessive amount, et al. In recent years, solar cells have attracted considerable interest because they are one of the most important ways to utilize sloar energy, and the research of sloar cells has made great progress. At present, research of solar cells mainly focus on improving the power conversion efficiency and reducing the costs.Copper phthalocyanine (CuPc) has been used extensively as electron donor in organic solar cells due to its marked photovoltaic effect and photoconductivity characteristics. So far, the power conversion efficiency of organic solar cell based on CuPc have been achieved 5.58% in laboratory. However, low power conversion efficiency is still a major obstacle to the device application. Therefore, efforts to improve the photovoltaic properties of solar cell based on CuPc is still needed to made.In this thesis, we aimed at research of solar cells based on copper phthalocyanine, and carried out beneficial exploration in the following three aspects mainly:1. Three different bulk heterojunction solar cells have been fabricated using the poly (2-methoxy-5-(2’-ethyl-hexyloxy)-1,4-phenylene vinylene) (MEH-PPV) and copper phthalocyanine (CuPc) as electron donors, and with 1-(3-methoxycarbonyl)-propyl-1-1-phenyl-(6,6) C61 (PCBM) as electron acceptor. Dramatically increased absorption spectra coverage was achieved by doping the CuPc to the blended films of MEH-PPV and PCBM, which improved the ability of absorbing the photons. The incorporation of CuPc showed further PL intensity quenching due to the separation of the photo-generated charges. Further, the current-voltage characteristics showed that the performance of cells achieved the best one when the CuPc approaches to 50% in weight compared with that of the MEH-PPV.2. Hybrid solar cell based on CuPc and n-Si with textured structure has been fabricated. Effects of texturization on the performance of CuPc/n-Si hybrid solar cell was discussed. Moreover, Electrochemical Impedance Spectroscopy (EIS) has been used to analyze charge carrier transport mechanism of solar cell. The equivalent circuit model consisting of a parallel resistor and capacitor in series with a resistor gives a good fit to the experimental data, which is applicable to cell’s structure. The conduction mechanism was suggested to be a space-charge limited current with exponential trap distribution.3. Well-aligned ZnO nanorod array, synthesized by wet chemical bath deposition (CBD) method on conductive indium-tin-oxide (ITO) substrate. Surface photovoltage (SPV) technique based on a scanning Kelvin Probe system was employed to investigate the optoelectronic behavior of ZnO nanorod array. The surface photovoltage and its time-resolved evolution process are used to determine the energy level structure of the ZnO nanorod array. Kelvin Probe technique also was used to study the photovoltaic properties of the copper-phthalocyanine (CuPc), and CuPc/ ZnO nanorod array system. Moreover, Surface photovoltage (SPV) technique based on a lock-in amplifier was employed to study the photovoltaic properties of the copper-phthalocyanine (CuPc) and ZnO nanorod array system affected by ethanol. Several useful results and experience were obtained, which will benefit practical photoelectric applications based on ZnO nanorods and CuPc.更多还原