Cavendish Laboratory, Cambridge University, J.J. Thomson Avenue, Cambridge, CB3 0HE, United Kingdom.
Nano Lett. 2010 Mar 10;10(3):1063-9. doi: 10.1021/nl100080r.
In this letter, we examine the effect of charge trapping on geminate recombination and organic photovoltaic performance using a Monte Carlo model. We alter the degree of charge trapping by considering energetic disorder to be spatially uncorrelated or correlated. On correlating energetic disorder, and so reducing the degree of trapping, it is found that power conversion efficiency of blend and bilayer devices improves by factors of 3.1 and 2.6, respectively. These results are related to the experimental data and quantum chemical calculations for poly[9,9-dioctylfluorene-co-bis-N,N'-(4-butylphenyl)-bis-N,N'-phenyl-1,4-phenylenediamine] (PFB)/poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT) as well as poly(3-hexylthiophene) (P3HT)/(6,6)-phenyl-C(61)-butyric acid methyl ester (PCBM) solar cell systems. The minimization of traps at the heterojunction between electron- and hole-accepting materials, perhaps by molecular design, appears to be a promising strategy to achieve large gains in PV performance. It is also shown that macroscopically measurable quantities such as mobility and energetic disorder are not necessarily good predictors of nanoscale geminate recombination process.
在这封信中，我们使用蒙特卡罗模型研究了电荷俘获对孪生复合和有机光伏性能的影响。我们通过考虑能量无序是空间上不相关还是相关来改变电荷俘获的程度。在相关的能量无序下，以及减少俘获的程度，发现共混和双层器件的功率转换效率分别提高了 3.1 倍和 2.6 倍。这些结果与聚9,9-二辛基芴-co-双-N,N'-(4-丁基苯基)-双-N,N'-苯基-1,4-苯二胺/聚(9,9-二辛基芴-co-苯并噻二唑)(F8BT)以及聚(3-己基噻吩)(P3HT)/(6,6)-苯基-C(61)-丁酸甲酯(PCBM)太阳能电池系统的实验数据和量子化学计算有关。通过分子设计，在电子和空穴受体材料之间的异质结处最小化陷阱，似乎是实现光伏性能大幅提高的有前途的策略。研究还表明，宏观上可测量的量，如迁移率和能量无序，不一定是纳米级孪生复合过程的良好预测指标。
