基于Al_2O_3/MoO_3复合阳极缓冲层的倒置聚合物太阳能电池的研究

Enhanced performance of inverted polymer solar cell based on Al_2O_3/MoO_3 as composite anode buffer layer

采用旋涂Al_2O_3前驱体溶液和低温退火的方法在活性层上形成Al_2O_3薄膜,并与MoO_3结合形成Al_2O_3/MoO_3复合阳极缓冲层,制备了以聚3-己基噻吩:[6.6]-苯基-C_(61)-丁酸甲酯(P3HT:PC_(61)BM)为活性层的倒置聚合物太阳能电池,并通过改变Al_2O_3前驱体溶液的浓度来分析复合阳极缓冲层对器件性能的影响.结果发现,Al_2O_3/MoO_3复合阳极缓冲层能有效调控倒置聚合物太阳能电池的光电性能及其稳定性.当Al_2O_3前驱体溶液的浓度为0.15%时,器件光伏性能达到最优值,与MoO_3单缓冲层的器件相比,光电转换效率(PCE)由3.85%提高到4.64%;经过80天老化测试后,具有复合阳极缓冲层的器件PCE保留为初始值的76%,而单缓冲层的器件PCE已经下降到50%以下.器件性能得到改善的原因是Al_2O_3/MoO_3复合阳极缓冲层增强了倒置太阳能电池器件阳极对空穴的收集能力,同时钝化了器件活性层,从而提升了太阳能电池器件的光伏性能及其稳定性.

Inverted polymer solar cell with P3HT：PC61BM as an active layer is fabricated based on Al2O3/MoO3 composite anode buffer layer. Effects of Al2O3/MoO3 composite anode buffer layers with the Al2O3 precursor solutions of different concentrations on the device performance are investigated. It can be found that the Al2O3/MoO3 composite anode buffer layer can effectively enhance the photovoltaic performance and device stability of inverted polymer solar cell. The open- circuit voltage （Voc）, short-circuit current （Jsc）, filling factor （FF）, and photoelectric conversion efficiency （PCE） are 0.64 V, 8.62 mA/cm2, 63.86%, and 3.85% respectively for the control device with MoO3 single buffer layer. In addition, with the increase of the concentration of A12O3 precursor solution, the photovoltaic performance of the inverted polymer solar cell with Al2O3/MoO3 composite anode buffer layer is gradually improved. For the Al2O3 precursor solution of 0.15%, the photovoltaic performance of the device reaches an optimal value, and the corresponding Voc, Jsc, FF, and PCE are 0.65 V, 11.04 mA/cm^2, 64.46%, and 4.64%, respectively. The Jsc and PCE significantly increase by 28% and 20%, respectively, compared with those of the control device with MoO3 single buffer layer. Moreover, after 80 days of measuring the device lifetime, the PCE of the device with the composite anode buffer layer remains at 76% of the original value while the PCE with the single buffer layer is reduced below 50%. The improvement of the device performance should be attributed to the PC61BM receptor near the anode dissolved and washed by isopropyl alcohol solvent from the Al2O3 precursor solution. At the same time, a large number of pits on the surface of the active layer are filled with Al2O3 to make it more smoothly contact the composite anode buffer layer. Therefore, the contact resistance between the active layer and the anode decreases, which enhances hole collection performance of the anode. Simultaneously, the Al2O3 layer can passivate the active layer of the device, thus improving the photovoltaic performance and device stability of inverted polymer solar cell.