【作者】 王勇；

【导师】 何志群；

【作者基本信息】 北京交通大学 ， 光学工程， 2011， 硕士

【摘要】 有机／聚合物太阳能电池具有低成本、良好的机械性和柔韧性、化学结构可操作性等优点,在光伏领域具有良好的发展前景。当前基于P3HT:PCBM的光伏器件能量转换效率已经超过8%,但仍未达到商业化的标准。目前,有机光伏的研究的热点集中于材料的选择和器件结构的优化两方面。本文选择P3HT:PCBM为材料,从优化器件结构着手,研究了不同活性层厚度和热处理温度对器件性能的影响。1、本文首先研究了活性层厚度与旋涂机转速的关系,通过调节转速制备了9种不同活性层厚度的太阳能电池,结构为ITO/PEDOT:PSS/P3HT:PCBM (Xnm)/Al。测试了各对比器件的I-V曲线和吸收光谱,并计算了器件的串并联电阻。激子扩散长度与膜厚有关,电极收集电荷的效率受激子扩散长度影响。研究得出：当器件的活性层厚度为110nm时,激子扩散长度与激子分离界面-电极间的距离的差值最大,电极收集电荷最有效。器件的主要参数为Voc=0.64V、JSC=9.22 mA/cm2、FF=0.42、PCE=4.49%.,而活性层厚度为65nm时,器件的吸收最好,但给受体间接触面较小,导致激子分离效率较低；热处理可使P3HT的HUMO能级发生变化,但变化程度随器件活性层厚度的变化而变化。2、我们制备了8组结构完全相同的聚合物光伏器件,采用不同退火温度对8组器件进行热处理30分钟,然后测试个器件的I-V曲线、吸收光谱和外量子效率,并计算了各器件的串并联电阻。对所有参数进行归一化的整合后进行对比,发现当器件退火温度为145℃时,器件的性能最好,能量转换效率为4.09%,开路电压0.64V,短路电流密度9.23 mA/cm2,填充因子38%,串联电阻21.9ohm,并联电阻197.30hm。。热处理可使P3HT发生结构性变化,并且使复合膜内部排列更加规整,减少串联电阻,增加光吸收。本实验结果也表明,在退火时间为30分钟的前提下,P3HT发生结构性变化的温度在115℃-120℃之间。更多还原

【Abstract】 Organic solar cells have shown great promising potential because it is mechanical flexible and durable, and the chemical structure can be easily manipulated. Recently, the power conversion efficiency of organic solar cells worked on P3HT:PCBM has already broken through 8%.Recent researches are concentrating on new materials and structure optimization, so we select P3HT:PCBM to research the effect by thin film thickness and anneal temperature.First, we researched the relationship between the rotation speed and film thickness of P3HT:PCBM, then we fabricated 9 devices with different thickness and the structure of ITO/PEDOT:PSS/P3HT:PCBM(X nm)/Al. And their I-V curves and absorbance spectrum were compared. We also calculate the series resistance and grid resistance. Exciton diffusion length is affected by the film thickness. Through the discussion, we know the power conversion efficiency is the highest while the film thickness is 110nm, exciton diffusion length minus the distance between the interface of exciton dissociation and electrodes is very big. The absorbance spectrum is best while the thickness is 65nm, but the contact area between the D and A is very small. HUMO of P3HT can be changed by annealing, but the variation is decided by the thickness.Second, the structure with ITO/PEDOT:PSS/P3HT:PCBM(110nm)/Al were fabricated. We used different temperatures to anneal the device for 30min, then we compared their I-V curves absorbance spectrum and EQE. Then calculate the series resistance and grid resistance, and compared their parameters including open circuit voltage, density of short-circuit current, series resistance, power conversion efficiency and fill factor. We found while the anneal temperature is 145℃, the device performance best. The power conversion efficiency can be enhanced by post-annealing which improve the morphology of P3HT:P3BM active layer.Besides, there is a lower series resistance and the solar cells based on P3HT:PCBM has a better morphology through a post-annealing at 145℃for 30min.We also found the temperature with structural changing of P3HT is between 115℃and 125℃更多还原