Risø National Laboratory for Sustainable Energy, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde, Denmark.
J Am Chem Soc. 2010 Dec 1;132(47):16883-92. doi: 10.1021/ja106299g. Epub 2010 Nov 5.
The spatial distribution of reaction products in multilayer polymer solar cells induced by water and oxygen atmospheres was mapped and used to elucidate the degradation patterns and failure mechanisms in an inverted polymer solar cell. The active material comprised a bulk heterojunction formed by poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) sandwiched between a layer of zinc oxide and a layer of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) that acted as, respectively, electron and hole transporting layers between the active material and the two electrodes indium-tin-oxide (ITO) and printed silver. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) in conjunction with isotopic labeling using H(2)(18)O and (18)O(2) enabled detailed information on where and to what extent uptake took place. A comparison was made between the use of a humid (oxygen-free) atmosphere and a dry oxygen atmosphere during testing of devices that were kept in the dark and devices that were subjected to illumination under simulated sunlight. It was found that the reactions taking place at the interface between the active layer and the PEDOT:PSS were the major cause of device failure in the case of these inverted devices, which are compatible with full roll-to-roll (R2R) coating and industrial manufacture. The PEDOT:PSS was found to phase separate, with the PEDOT-rich phase being responsible for most of the interface degradation in oxygen atmospheres. In water atmospheres, little chemically induced degradation was observed, whereas a large partially reversible dependence of the open circuit voltage on the relative humidity was observed. In addition, temporal aspects are discussed in regard to degradation mechanisms. Finally, analytical aspects in regard to storing devices are discussed.
水和氧气气氛下多层聚合物太阳能电池中反应产物的空间分布被绘制出来，并用于阐明倒置聚合物太阳能电池中的降解模式和失效机制。活性材料由聚（3-己基噻吩）（P3HT）和[6,6]-苯基-C61-丁酸甲酯（PCBM）形成的体异质结组成，夹在氧化锌层和聚（3,4-亚乙基二氧噻吩）聚（苯乙烯磺酸盐）（PEDOT：PSS）层之间，分别作为活性材料和两个电极铟锡氧化物（ITO）和印刷银之间的电子和空穴传输层。结合使用 H(2)(18)O 和 (18)O(2)的同位素标记的 X 射线光电子能谱（XPS）和飞行时间二次离子质谱（TOF-SIMS），可以详细了解吸收的位置和程度。在黑暗中保持和在模拟阳光下照射的情况下，对使用潮湿（无氧）气氛和干燥氧气气氛测试的器件进行了比较。结果发现，在这些倒置器件中，活性层和 PEDOT：PSS 之间界面发生的反应是器件失效的主要原因，这些器件与全卷对卷（R2R）涂层和工业制造兼容。发现 PEDOT：PSS 发生相分离，富 PEDOT 相是氧气气氛中大多数界面降解的原因。在水气氛中，观察到的化学诱导降解很少，而开路电压对相对湿度的部分可逆依赖性很大。此外，还讨论了降解机制的时间方面。最后，讨论了关于存储器件的分析方面。
