Electrical and optical properties, and functionality of conducting polymer - fullerene composite

在本研究中，我们制备了导电聚合物和富勒烯的复合材料，研究了它们的电学和光学性质，并利用该复合材料实现了新型的功能器件。当富勒烯与π共轭聚合物（如聚3-烷基噻吩）掺杂时，复合膜的光致发光强度随富勒烯浓度的增加而猝灭，但复合膜的光导电性随富勒烯浓度的增加而显著增强。这些现象可以用导电聚合物和富勒烯之间的光诱导电荷转移来解释，因为富勒烯在复合薄膜中作为电子受体与导电聚合物分离聚合物主链上的激子。由于电子的去除，主链上保留的正极化子有助于增强光电流。在导电聚合物-富勒烯复合材料中化学掺杂钾，观察到低场微波吸收和独特的电子自旋共振，表明在钾-富勒烯-导电聚合物复合材料中形成了超导相。在ESR测量中，如果将激发光额外照射到复合材料上，可以观察到稳定的ESR信号，该信号与复合材料中的极化子相一致。将有机给体材料注入复合材料中，可以观察到复合材料独特的铁磁性能。这种导电聚合物-富勒烯复合材料具有良好的光学、电学和磁学特性，是传感器、太阳能电池、超导器件、磁性器件等领域的理想材料。

In this study, we have fabricated composites of conducting polymer and fullerene, investigated their electrical and optical properties, and realized the novel functional devices by using the composites.In the case of doping fullerene with pi -conjugated polymer, such as poly(3-alkylthiophene), photoluminescence intensity of the composite film was quenched with increasing fullerene concentration, but the photoconductivity of the composite film was enhanced markedly depending on the fullerene concentration. These phenomena was explained by the photo-induced charge transfer between the conducting polymer and fullerene, because the fullerene plays an important role in the composite films as electron acceptors against the conducting polymers to dissociate the excitons on the polymer mainchains. Remained positive polarons on the mainchains due to the electron removal should contribute to the enhanced photocurrent.Chemical doping of potassium into the conducting polymer-fullerene composites could be available and the low-field microwave absorption as well as the unique electron spin resonance was observed, that indicates the formation of superconducting phase in the composite of potassium-fullerene-conducting polymer. In the ESR measurement, if the excitation light is irradiated onto the composites additionally, the stable ESR signal could be observed, that coincides with that of polarons in the composites. When the organic donor materials are clqed into the composites, the unique ferromagnetic properties could be observed.Such conducting polymer-fullerene composites, have much attractive optical, electrical, and magnetical characteristics, therefore, we emphasized that the composites should be candidates as the materials for sensors, solar cells, and superconducting devices, magnetic devices, and so on.