Photoinduced processes of the supramolecularly functionalized semi-conductive SWCNTs with porphyrins via ion-pairing interactions
Photoinduced processes of the supramolecularly functionalized semi-conductive SWCNTs with porphyrins via ion-pairing interactions
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DOI：
10.1039/c0ee00308e
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发表时间：
2011-03-01
影响因子：
32.5
通讯作者：
Ito, Osamu
中科院分区：
文献类型：
--
作者：
Das, Sushanta K.;Subbaiyan, Navaneetha K.;Ito, Osamu
离子对卟啉- swcnts纳米杂化物自组装的光诱导电子转移已被报道。为了实现这一目标，利用了两种不同直径的半导体SWCNTs，以及携带周围正电荷或负电荷的游离基或锌卟啉作为光吸收活性材料。供体-受体杂化物是通过离子配对的方式保持的，离子配对的方式是利用附着在SWCNTs侧壁上的带相反电荷的芘衍生物。带隙较窄的厚壁碳纳米管（7,6）比带隙较宽的薄壁碳纳米管（6,5）具有更高的电荷分离效率。使用这些供体-受体纳米杂交体修饰的FTO/SnO2电极进行的光电化学研究一致证明了这些纳米杂交体将光能转化为电能的能力。重要的是，光电流的产生遵循了电荷分离的趋势，即使用SWCNT的光电池的入射光子到电流的转换效率最高可达8%(7,6)，而由SWCNT衍生的光电池的转换效率则较小（6,5）。这些结果表明，通过选择带隙合适的SWCNTs或结合适当的卟啉，可以实现更高的光能转换效率。
Photoinduced electron transfer in self-assembled via ion-pairing porphyrin-SWCNT nanohybrids has been reported. To accomplish this, two kinds of semiconducting SWCNTs of different diameters, and free-base or zinc porphyrin bearing peripheral positive or negative charges serving as light absorbing photo-active materials are utilized. The donor-acceptor hybrids are held by ion-pairing with the help of oppositely charged pyrene derivatives adhered to the side walls of SWCNTs. Higher charge-separation efficiency is established for thick SWCNT(7,6) with narrower band gap compared with the thin SWCNT(6,5) with wider band gap. Photoelectrochemical studies using FTO/SnO2 electrodes modified with these donor-acceptor nanohybrids unanimously demonstrated the ability of these nanohybrids to harvest light energy into electricity. Importantly, the photocurrent generation followed the trend observed for charge-separation, that is, incident-photon-to-current conversion efficiency of a maximum of 8% is achieved for photocells with SWCNT(7,6), while such conversion efficiencies are smaller for the cells derived from SWCNT(6,5). These results indicate that higher light energy conversion efficiencies are possible to achieve by the selection of the appropriate SWCNTs with right band gap on combination of appropriate porphyrins.