【作者】 卓祖亮；

【导师】 张福俊；

【作者基本信息】 北京交通大学 ， 光学工程， 2011， 硕士

【摘要】 1986年,C.W. Tang提出了双层有机太阳能电池的结构；1995年,Heeger提出了体异质结太阳能电池的概念；二十一世纪,聚合物太阳能电池能量转换效率超过7%。经过二十多年的发展,聚合物太阳能电池取得了一个又一个的突破。本论文以P3HT:PCBM体系聚合物太阳能电池为主体,研究退火和碘掺杂前后器件性能的变化,分析了退火和碘掺杂对该体系太阳能电池性能的影响。得到以下两个结论：i)基于P3HT:PCBM的聚合物太阳能电池经过120℃、10min退火处理后,能量转换效率提高,从0.26%到2.00%；ii)有源层P3HT:PCBM中掺杂了质量比为5%的碘,短路电流密度从4 mA/cm2上升到8.7 mA/cm2,能量转换效率提高了38.5%。对比这两组实验,发现退火和碘掺杂都有效地提高了聚合物太阳能电池的性能。具体实验结果如下：利用旋涂方法制备了以P3HT:PCBM为有源层的聚合物太阳能电池。器件结构为ITO/PEDOT:PSS/P3HT:PCBM/Al,研究了退火温度对聚合物太阳能电池性能的影响。实验发现：聚合物薄膜经过120℃、10min退火处理后,开路电压达到0.64V,短路电流密度为10.25 mA/cm2,填充因子38.1%,光电转换效率达到2.00%。为了讨论其内在机制,对不同退火条件下聚合物薄膜进行了各种表征。从紫外-可见吸收光谱中发现,退火处理使P3HT:PCBM混合薄膜在可见光范围内吸收加强且吸收峰展宽,特别是在560和610 nm处的吸收强度明显增大；X射线衍射(XRD)结果表明,12℃退火后P3HT在(100)晶面上的衍射强度是未退火薄膜的2.8倍,有利于光生载流子的输运；原子力显微镜(AFM)研究结果表明,退火增大了P3HT:PCBM薄膜的相分离程度,提高了激子解离的几率；傅里叶变换红外(FTIR)光谱验证了退火并没有引起聚合物材料物性的变化。通过对有源层P3HT:PCBM进行不同比例的碘掺杂,制备了体异质结太阳能电池。当掺杂质量比为5%时得到最佳的性能,短路电流密度从4 mA/cm2上升到8.7mA/cm2,伴随着开路电压的略微减小,从0.63 V下降到0.52 V。最佳的能量转换效率达到1.51%。主要归因于可见光吸收的加强(吸收光谱红移、展宽),以及更好的载流子传输和收集。利用AFM测试了不同碘掺杂浓度有源层薄膜的相分离和表面形貌。掺杂了碘以后薄膜表面的相分离程度和表面粗糙度增大,有利于激子的解离,提高了P3HT:PCBM聚合物太阳能电池的性能。更多还原

【Abstract】 In 1986,C.W. Tang put forward the structure of the double layers organic solar cells. In 1995, Heeger proposed the concept of bulk-heterojunction solar cells. The 21st century, the power conversion efficiency of polymer solar cells increased to more than 7%. After twenty years of development, polymer solar cells (PSCs) have achieved breakthroughs in one after another. The thesis based on P3HT:PCBM bulk-heterojunction solar cells focus on the effect of annealing and doping treatments on the performance of PSCs. Get the following two conclusions:i) these devices were treated at 120℃for 10 min in an ambient atmosphere and the best power conversion efficiency (PCE) of 2.00% was obtained; ii) the distinguished enhancement of short circuit current density (Jsc) and the PCE of PSCs with 5% concentration iodine doping were obtained. Comparing annealing and iodine doping, both of them improve the performance of PSCs. Specific results are as follows:Several PSCs consisting of ITO/PEDOT:PSS/P3HT:PCBM/Al were fabricated by spin coating. The influence of annealing temperature on the performance of the polymer solar cells was studied using absorption spectra, photoluminescence spectra, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and atomic force microscopy (AFM). These devices were treated at 120℃for 10 min in an ambient atmosphere and the best power conversion efficiency (PCE) of 2.00% was obtained at an open circuit voltage (Voc) of 0.64 V, Jsc of 10.25 mA/cm2, and a fill factor (FF) of 38.1%. The intensities of the absorption peaks at 560 and 610 nm increased after annealing treatment. XRD spectra showed that the intensity of the diffraction peaks at (100) for P3HT increased 1.8 times by comparison with that of the cells that did not undergo annealing treatment. The P3HT:PCBM phase separation increased markedly after annealing treatment, which is valuable for exciton dissociation. FTIR results also showed that the polymer materials did not deteriorate during the annealing treatment process.A series of poly(3-hexylthiophene) (P3HT)/(6,6)-phenyl C60 butyric acid methyl ester (PCBM) bulk hetero-junction polymer solar cells were fabricated with different iodine (I2) doping concentrations. The Jsc was increased to 8.7 mA/cm2 from 4 mA/cm2, meanwhile Voc was decreased to 0.52V from 0.63V when the iodine doping concentration is 5%. The optimized PCE of PSCs with iodine doping is about 1.51%, which should be attributed to the better charge carrier transport and collection, and the more photon harvesting due to the red shift of absorption peaks and the widened absorption range to the longer wavelength. The morphology and phase separation of polymer thin films were measured by AFM. The phase separation of P3HT and PCBM has been distinctly increased, which is beneficial to the exciton dissociation. Improve the performance of P3HT:PCBM PSCs.更多还原