Influence of perfluorinated ionomer in PEDOT:PSS on the rectification and degradation of organic photovoltaic cells
Influence of perfluorinated ionomer in PEDOT:PSS on the rectification and degradation of organic photovoltaic cells
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DOI：
10.1039/c8ta04098b
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发表时间：
2018-09-07
影响因子：
11.9
通讯作者：
Andre, Pascal
中科院分区：
文献类型：
--
作者：
Howells, Calvyn T.;Saylan, Sueda;Andre, Pascal
聚（3，4-乙撑二氧噻吩）：聚（苯乙烯磺酸盐）（PEDOT：PSS）被广泛用于构建光电器件。然而，作为一种吸湿的水基酸性材料，它带来了稳定性和降解的主要问题，导致在有机光伏（OPV）器件中取代它的努力。在这项工作中，我们专注于全氟离聚物（PFI）聚合物添加剂PEDOT：PSS。我们证明，它可以降低OPV器件老化的相对幅度，并找到两个不同的制度的影响。在低浓度下，对润湿和功函数有微妙的影响，例如，对器件特性有不利影响，并且在阈值以上，它会改变电子和器件特性。PFI浓度大于或等于PSS浓度时，导电聚合物中出现突变阈值，并通过监测透射率、形貌、功函数、润湿性和OPV器件特性的变化来揭示。低于该PFI浓度阈值，基于聚（3-己基噻吩-2，5-二基）：[6，6]-苯基-C-61-丁酸甲酯（P3 HT：PCBM）的OPV的功率转换效率（PCE）在很大程度上受到由于差的电荷提取引起的低填充因子的损害。在PFI浓度阈值以上，我们在PCE被改善超过原始的基于PEDOT：PSS层的OPV器件之前恢复PCE。作为性能增强的补充，PFI提高了OPV器件的稳定性和寿命。我们的降解研究得出的结论是，PFI防止水扩散到吸湿性PEDOT：PSS层和从吸湿性PEDOT：PSS层扩散，这减缓了PEDOT：PSS层和铝电极的劣化。这些发现揭示了在开发抑制OPV降解的成分时应考虑的机制和机会。
Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is widely used to build optoelectronic devices. However, as a hygroscopic water-based acidic material, it brings major concerns for stability and degradation, resulting in an intense effort to replace it in organic photovoltaic (OPV) devices. In this work, we focus on the perfluorinated ionomer (PFI) polymeric additive to PEDOT:PSS. We demonstrate that it can reduce the relative amplitude of OPV device burn-in, and find two distinct regimes of influence. At low concentrations there is a subtle effect on wetting and work function, for instance, with a detrimental impact on the device characteristics, and above a threshold it changes the electronic and device properties. The abrupt threshold in the conducting polymer occurs for PFI concentrations greater than or equal to the PSS concentration and was revealed by monitoring variations in transmission, topography, work-function, wettability and OPV device characteristics. Below this PFI concentration threshold, the power conversion efficiency (PCE) of OPVs based on poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C-61-butyric acid methyl ester (P3HT:PCBM) are impaired largely by low fill-factors due to poor charge extraction. Above the PFI concentration threshold, we recover the PCE before it is improved beyond the pristine PEDOT:PSS layer based OPV devices. Supplementary to the performance enhancement, PFI improves OPV device stability and lifetime. Our degradation study leads to the conclusion that PFI prevents water from diffusing to and from the hygroscopic PEDOT:PSS layer, which slows down the deterioration of the PEDOT:PSS layer and the aluminum electrode. These findings reveal mechanisms and opportunities that should be taken into consideration when developing components to inhibit OPV degradation.