Formation and photoinduced properties of zinc porphyrin-SWCNT and zinc phthalocyanine-SWCNT nanohybrids using diameter sorted nanotubes assembled via metal-ligand coordination and π-π stacking
Formation and photoinduced properties of zinc porphyrin-SWCNT and zinc phthalocyanine-SWCNT nanohybrids using diameter sorted nanotubes assembled via metal-ligand coordination and π-π stacking
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DOI：
10.1142/s1088424611003951
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发表时间：
2011-09-01
影响因子：
1.5
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
研究了自组装锌卟啉（ZnP）和酞菁锌（ZnPc）与半导体（7，6）和（6，5）富集的单壁碳纳米管（SWCNTs）的光诱导电子转移过程。为了将光敏剂结合到SWCNT，首先，用SWCNT处理用苯基咪唑（Im-Pyr）实体共价官能化的芘。剥离的单壁碳纳米管发生由于芘与纳米管壁的π-π堆叠，留下咪唑实体，随后用于协调邻二氯苯（DCB）中的ZnP或ZnPc。通过TEM成像、稳态紫外-可见-近红外吸收光谱和荧光光谱对所形成的给体-受体纳米杂化物进行了表征。自由能计算表明，在纳米杂化物中，电子可能从光激发的ZnP或ZnPc转移到Im-Pyr/SWCNT（n，m）。因此，稳态和时间分辨荧光研究显示ZnP或ZnPc的单重激发态的有效猝灭，电荷分离速率常数（k（CS））在（3-6）x 10（9）s（-1）的范围内。纳秒瞬态吸收技术证实了电子转移产物ZnP中心点+
Photoinduced electron transfer processes in self-assembled zinc porphyrin (ZnP) or zinc phthalocyanine (ZnPc) with semiconducting (7,6)- and (6,5)-enriched SWCNTs were investigated. To bind photosensitizers to SWCNTs, first, pyrene covalently functionalized with a phenylimidazole (Im-Pyr) entity was treated with SWCNTs. Exfoliation of SWCNTs occurred due to pi-pi stacking of pyrene with nanotubes walls leaving the imidazole entity that was subsequently used to coordinate ZnP or ZnPc in o-dichlorobenzene (DCB). The donor-acceptor nanohybrids thus formed were characterized by TEM imaging, steady-state UV-visible-near IR absorption and fluorescence spectra. Free-energy calculations suggested possibility of electron transfer from the photoexcited ZnP or ZnPc to Im-Pyr/SWCNT(n,m) in the nanohybrids. Consequently, steady-state and time-resolved fluorescence studies revealed efficient quenching of the singlet excited state of ZnP or ZnPc with the rate constants of charge separation (k(CS)) in the range of (3-6) x 10(9) s(-1). Nanosecond transient absorption technique confirmed the electron transfer products, ZnP center dot+