胶束辅助的酞菁给体-碳纳米管受体超分子自组装及光诱导长寿命电荷分离态

Self-assembly of Phthalocyanine-carbon Nanotubes Dispersed in Micelle and Light Induced Long-lived Charge Separation State

利用十二烷基硫酸钠(SDS)阴离子胶束能够稳定分散单壁碳纳米管(SWCNT)和解聚富集四磺酸锌酞菁(ZnPcS4)的能力,组装了ZnPcS4-SWCNT的电子给体-受体对来模拟光合作用的原初电子转移过程.用稳态和时间分辨荧光法研究了相应的给体-受体分子间和分子内的光诱导电子转移速率,用激光闪光光解技术检测了生成的电荷分离态.ZnPcS4-SWCNT的电子给体-受体组装体在707 nm处出现了基态特征吸收峰,但是复合体不产生荧光,这主要归因于有效的分子内光诱导电子转移过程.瞬态吸收光谱检测到相应的离子对,动力学衰减结果表明,电荷分离态的寿命长达42μs.这一长寿命电荷分离态的形成,主要是因为ZnPcS4是良电子给体(低氧化电位),SWCNT是好的电子受体,使得三重态电子转移能够发生,生成三重态电荷分离态.

To mimic the primary process in photosynthesis,tetrasulfonated zinc phthalocyanine（ZnPcS4） and single-walled carbon nanotubes（SWCNT） were assembled to noncovalent electron donor-acceptor（D-A） complex assisted by sodium dodecyl sulfate（SDS） micelle,which disaggregate both SWCNTs and phthalocyanines in aqueous solution.The D-A complex is featured by the new absorption at 707 nm and completely non fluorescence,due to the efficient intra-molecular photo induced electron transfer revealed by both steady state and time resolved fluorescence spectra.The charge separation state（CSS） was observed by laser flash photolysis and showed a long lifetime of 42 μs observable by kinetic analysis.The long-lived CSS is due to the triplet electron transfer which is made possible by the low oxidation potential of the phthalocyanine（good donor） and the low reduction potential of SWCNT（good acceptor）.The result shows that SWCNT may be applied in artificial photosynthesis.