Chuang Ming-Kai, Chen Fang-Chung
Department of Photonics, National Chiao Tung University, Hsinchu 30010, Taiwan.
ACS Appl Mater Interfaces. 2015 Apr 8;7(13):7397-405. doi: 10.1021/acsami.5b01161. Epub 2015 Mar 25.
Metal nanostructures that trigger plasmonic near-field effects are often incorporated in organic photovoltaic devices (OPVs) to improve their light-harvesting ability. These nanostructures usually can be positioned in two different locations in a device: (i) within the photon absorption layers and (ii) at the interfaces between the active layer and the metal electrodes. In this study, we developed amphiphilic gold nanoparticles (Au NPs) for use in dual plasmonic nanostructures within OPVs. We employed graphene oxide as the template to anchor the Au NPs, thereby avoiding their aggregation. Furthermore, we added poly(ethylene glycol) (PEG) bis(amine) to the synthesis medium to improve the solubility of the nanocomposites, such that they could be dispersed well in water and in several organic solvents. Accordingly, we could incorporate the PEGylated Au NP/graphene oxides readily into both the buffer layer and photoactive layer of OPVs, which, as a result, exhibited obvious enhancements in their photocurrents and overall device efficiencies. Moreover, we observed different spectral enhancement regions when we positioned the nanocomposites at different locations, reflecting the different dielectric environments surrounding the NPs; this unexpected behavior should assist in enhancing the broadband absorption of solar irradiation.
触发等离子体近场效应的金属纳米结构常被用于有机光伏器件（OPV）中，以提高其光捕获能力。这些纳米结构通常可位于器件中的两个不同位置：（i）光子吸收层内；（ii）活性层与金属电极之间的界面处。在本研究中，我们开发了用于OPV中双等离子体纳米结构的两亲性金纳米颗粒（Au NPs）。我们采用氧化石墨烯作为模板来锚定Au NPs，从而避免其聚集。此外，我们向合成介质中添加聚乙二醇（PEG）双胺以提高纳米复合材料的溶解度，使其能够很好地分散在水和几种有机溶剂中。因此，我们可以将聚乙二醇化的Au NP/氧化石墨烯轻松地掺入OPV的缓冲层和光活性层中，结果，这些层的光电流和整体器件效率都有明显提高。此外，当我们将纳米复合材料置于不同位置时，观察到了不同的光谱增强区域，这反映了NP周围不同的介电环境；这种意外行为应有助于增强太阳辐射的宽带吸收。
