基于聚多巴胺/氧化锌复合阴极缓冲层的倒置聚合物太阳能电池的研究

Mechanism of inverted polymer solar cells based on poly(dopamine)/ZnO as composite cathode buffer layer

利用多巴胺氧化自聚合形成聚多巴胺(PDA)与ZnO结合形成PDA/ZnO复合阴极缓冲层,制备了以P3HT:PC_(61)BM为活性层的倒置结构聚合物太阳能电池,通过改变PDA的自聚合时间来分析复合阴极缓冲层对器件性能的影响.实验发现,随着PDA的自聚合时间的增加,聚合物太阳能电池的光电转换效率先增大后减小,当自聚合时间为10 min时,相应器件光伏性能达到最优值,其开路电压V_(OC)为0.66 V,短路电流密度J_(SC)为9.70 mA/cm^2,填充因子FF为68.06%,光电转换效率PCE为4.35%.器件性能改善的原因是由于PDA/ZnO复合阴极缓冲层减小了ZnO与ITO之间的接触电阻,同时PDA中存在大量的氨基有利于倒置太阳能电池阴极对电子的收集.

Inverted polymer solar cells with P3HT：PCBM as active layer are fabricated based on poly（dopamine）/ZnO（PDA/ZnO） as composite cathode buffer layer. Effects of PDA/ZnO composite cathode buffer layer with the different self-polymerization times on the device performance are investigated. According to the results, the short circuit current and photoelectric conversion efficiency of polymer solar cells first increase then decrease with the increase of the self-polymerization time of PDA. For 10-min PDA self-polymerization, the photovoltaic performance of the device achieves the optimal values： open circuit voltage 0.66 V, short circuit curent density 9.70 mA/cm^2, fill factor 68.06%,and power conversion efficiency 4.35% under irratiation of light with a strength of 100 mW/cm^2. We conclude that the improvement of device performance is due to the PDA/ZnO composite cathode buffer layer reduced the contact resistance between the ZnO and ITO, at the same time, the presence of a large number of nitrogen groups in PDA is advantageous for the electronic collection of the inverted polymer solar cells. Meanwhile, polymer solar cell with PDA/ZnO as composite cathode buffer layer also exhibits excelent stability. In addition, PDA has a strong adhesive force that makes the ZnO interface layer on its surface not easy to fall off. This provides a new way of fabricating the flexible polymer solar cell devices.