Langmuir-Blodgett单分子膜功能体系的研究——(Ⅰ)膜系间敏化荧光的Förster机制

利用L-B技术制作L-B功能单分子膜。以两种花菁染料作给体和受体,用硬脂酸单分子膜作隔离夹层。在这种体系中的能量转移是Förster机制,有效距离为～100。

INVESTIGATION OF FUNCTIONAL LANGMUIR-BLODGETT MGNOLAYER ASSEMBLIES (Ⅰ) Förster Mechanism of Sensitized Fluorescence in the Case of Insulating Interlayers

This paper reports the study on making functional molecular monolayer assemblies by means of Langmuir-Blodgett technique and discusses energy transfer from the donor to the acceptor monolayers. There appears J-aggregate in the mixed monolayer of the NN’-dioctade-cyloxacyanine and hexadecane with the molar ratio of dye:hexadecane=1:1. The J-aggregate state,in fact,is an exciton state and it is possible that there is exciton transfer. This consideration leads to the conception of a functional unit of different components combining energy transfer processes. The structures of the assembled systems are shown in Fig.4. The mixed monolayer L-B assemblies of NN’-ditadecyloxacyanine as donor and NN’-dioctadecyloxacarbocyanine as acceptor are constructed into the energy transfer systems, (a) L-B monolayer assembly of the oxacyanine(molar ratio of dye:hexadecane=1:1).(b)L-B monolayer of the oxacarbocyanine as acceptor (molar ratio of dye:hexadecane=1:1) covers on the assembly of the oxacyanine as donor. The molecular chromophores of the two layers contact each other. (c) The monolayers of donor and acceptor are separated by two monolayers of stearic acid. The distance between donor and acceptor molecules is about 50Å (d) The donor monolayer and the acceptor monolayer are separated by four stearic acid monolayers in the same way. (e) The stearic acid sandwich assembley is six layers. Thefive systems are irradiated by 366nm ultraviolet ray respectively System (a) gives blue fluorescence of the oxacyanine molecules Systems(b), (c), (d) give green fluorescence of the acceptor with the intensities(b)>(c)>(d). In addi tion, part of the emission of system(d) is the blue fluorescence. System(e) does not show green fluorescence,only the blue fluorescence of the donor is observed. The result of above-mentioned experiments shows that the energy transfer between L-B functional monolayers is with Förster radiationless energy transfer mechanism.