【作者】 李卫民；

【导师】 孙秀泉；

【作者基本信息】 华中科技大学 ， 光学工程， 2009， 博士

【摘要】 聚合物太阳能电池，迄今为止以其原料价格低廉、生产工艺相对简单、可以大面积制造等为特点。同时，各种各样日臻成熟的制备聚合物薄膜的方法之出现，亦为电池的制备提供了有力的支撑。这样，使得聚合物太阳能电池成为目前该领域的研究热点之一。本论文针对聚合物太阳能电池的机理及实验进行了较为深入的探索，旨在提高器件光电转换效率。本论文的主要工作，是从聚合物太阳能电池器件结构优化入手，在研究电池光电转换过程以及损耗机理的基础上，利用Matlab软件，模拟分析了有机电池输出特性、光子吸收特性和载流子输运特性：在此基础之上制备了基于P3HT／PCBM和MDMO-PPV／PCBM的两种复合体聚合物太阳能电池，并进行了实验验证。找到了电池材料给体受体合适的混合比例、合适的成膜溶剂；研究了对复合体膜进行热处理，以及增加缓冲层等这些提高聚合物太阳能电池性能的重要途径。首先，建立了有机太阳能电池的等效电路模型，利用Matlab软件生成了有机电池输出特性仿真系统，模拟了有机太阳能电池的输出特性。同时还对有机太阳能电池的串联电阻和分流电阻对输出特性的影响进行了仿真研究。进而，为了验证模型的合理性，制备了基于P3HT／PCBM的复合体结构聚合物有机太阳能电池并实测数据，同时还将仿真结果与其它的实验结果进行对比分析，发现数值模拟和实验结果符合较好，从而证明所建立的电路模型，对描述有机太阳能电池的输出特性可靠。之后，以P3HT／PCBM的复合体结构有机太阳能电池参数为基础，建立了复合体异质结器件光子吸收模型和载流子输运模型，模拟了基于P3HT／PCBM的复合体结构有机太阳能电池光吸收和电荷输运过程，分析和实验结果都表明，对于体异质结有机太阳能电池，都存在最佳参数可以提高光电转换效率。综上所述，本工作对聚合物太阳能电池，从理论和实验两方面，进行了有益的探索。从理论上，利用光学干涉效应、电荷漂移和扩散理论，建立了等效电路模型、光子吸收模型、载流子输运模型和输出特性仿真系统；在实验上，系统研究了电池材料给体受体的混合比例、成膜选择的溶剂，以及对复合体膜进行热处理和增加缓冲层等对有机太阳能电池转换效率的影响，得到了具有实际指导意义和理论参考价值的结果：研究表明，复合体中给体受体材料(D／A)比例不同，会直接影响成膜的表面形貌，改变给体相和受体相的分离状况，从而影响电池的开路电压和短路电流；选择不同溶剂成膜制备的聚合物太阳能电池，得到不同的薄膜表面微相结构状态；对制备的电池进行热处理，可以形成良好的微相分离及导电网络，有利于电荷的传输，增大器件的短路电流，提高填充因子；在有机活性层和ITO基底之间，以及有机活性层和电极之间插入缓冲夹层，同样可提高器件的开路电压和短路电流。更多还原

【Abstract】 Polymer solar cells are by far characterized of low-cost raw material, simple process and being produced in large area. Meanwhile, the advent of various increasing mature methods of making process for polymer film is a beneficial guarantee for the production of polymer solar cells. Therefore, the polymer solar cells become one of the heat pots of present research area.With the purpose of enhancing the transformation efficiency of photovoltaic devices, an intensively exploration has been made on the mechanism and experiment study of polymer solar cell and some new results has been achieved.This paper, starting with the optimization of the mechanism of polymer solar cells, researches the process of optic-electric transformation and loss mechanism, simulates the output properties of organic solar cell, optical absorption, and charge carriers transport by Matlab, then makes the polymer solar cells based on the complex of P3HT/PCBM and MDMO-PPV/PCBM, carries out the experiment, discovers the proper proportion of donor and acceptor and solvent and founds device annealing and spinning interlayer are the important ways to enhance the performance of polymer solar cells.To imitate the influence of organic solar cell, mechanism and equivalent circuit of organic solar cell were analyzed and the computer simulation mode on properties of organic solar cell was established. We prepared bulk heterojunction organic solar cells, and the comparison showed that there was coincidence between the results of simulation and experiment.Based on optical interference and carrier transport principle, we propose models of the organic polymer bulk heterojunction photovoltaic cells. The functional relation of exciton generation rate, carrier densities and short circuit current densities versus the depth of the film has been simulated and analyzed, and the model is validated by experiment. We demonstrate that model can be useful for the organic photovoltaic cells with high power conversion efficiency.Above all, this paper for the first time investigates the polymer solar cells both in theory and in experiments from a new perspective. Theoretically, equivalent circuit of organic solar cell, models of incoherent optical absorption and charge carriers transport, simulation system of output properties of organic solar cells, were established according to the optical principle and diffusion theory; experimentally, the effect on solar cell’s conversion efficiency of proportion of donor and acceptor,solvent select , device annealing and spinning interlayer have been systematically researched. The result is both practical and learned with high value.The research shows that the different proportion of donor and acceptor changed device’s open circuit voltage and short circuit current, improved performance of devices. Solvent select also changed film’s microstructure and improve organic solar cells’ performance. We have studied the effect of thermal annealing on the performance of bulk heterojunction solar cells. We explain the observed trends in device characteristics in terms of differences in the film morphology. Thermal annealing provides interfaces and pathways for charge transfer, and to maximize the photo-induced charge separation, improving power conversion efficiency of polymer solar cells. The effect of spin-casting interface buffer layer on the performance of Donor/Acceptor bulk hetero-junction organic polymer photovoltaic cells was studied in this paper. Comparing the devices with and without buffer layer, the open-circuit voltage and short-circuit current of the device with buffer layer were influenced, and the solar cell’s conversion efficiency was improved as well.更多还原