Study On The Micro-region Structures And Properties Of Azobenzene Langmuir-blodgett Films

Azobenzene dyes, due to its unique nature aroused great interest in optoelectronics. The electronicstructure, electron transfer, and other physical and chemical properties of micro-region structure research isan important topic for the development of molecular electronics. It is also the precondition for applicationto position assembly precisely and property investigation. In this paper, the azobenzene dye ofEthyl4-((4-(4-bromobutoxy)phenyl)diazenyl)benzoate(AZO-1),4-((4-hexadecylphenyl)diazenyl)aniline(AZO-2),3-hydroxy-N-(4-methoxyphenyl)-4-(phenyldiazenyl)-2-naphthamide (AS-RL),2-Naphthalenecarboxamide,3-hydroxy-N-(4-nitrophenyl)-4-(2-phenyldiazenyl)（AS-BS）and their hybridLB films with arachidic acid (AA), behenic acid (BA) and octadecylamine (ODA) were assembled byLangmuir-Blodgett (LB) technique. UV-vis absorption spectroscopy, fluorescence spectroscopy andscanning probe microscope were used to study their structure and properties. The results revealed thatstable, well-defined, and well-organized LB films were formed in pure water. AA, BA and ODA canmodulate and control the structure of the dye aggregates. We study on the micro-region electrical propertiesand macro-region optical (electrical) properties of these assemblies. This article involves the work of threeparts as followed:1. Study on the micro-region structure and optical properties of azobenzene dyes with–COO and–NH2groups LB filmsA monolayer of new azobenzene dye of AZO-1and AZO-2has been transferred onto solid substratesby the Langmuir-Blodgett technique. As auxiliary film-forming materials, some additives such as BA andODA were introduced to modulate and control the structure of the dye aggregates. And the micro-regionstructure and optical properties of the mixed LB films were studied. The results show that the Langmuirfilms of AZO-1and AZO-2formed network structure.2. Study on the micro-region structure of azobenzene with–CH3O and-NO2groups LB filmsA monolayer of new azobenzene dye of AS-RL and AS-BS has been transferred onto different solidsubstrates and at different surface pressure by the Langmuir-Blodgett technique. Some additives such as AA and ODA were introduced, the proportion of which was adjusted to assemble the mixed LB films andthe micro-region structure of the mixed LB films was studied. The results showed that the Langmuir filmsof AS-RL and AS-BS separately formed lined and rod-like structures.3. Study on the optical and electrical properties of azobenzene with-NO2LB filmsThe azobenzene dye of AS-BS and its hybrid LB films with AA, ODA were assembled byLangmuir-Blodgett (LB) technique. The micro-region structure of the mixed LB films was studied byatomic force microscopy. The results showed that the Langmuir films of AS-BS and their hybrid filmsformed H aggregates. Optical properties were tested by UV-vis and fluorescence spectrophotometer. Themicro-region electrical properties were tested by Semiconductor Characteristic Measurement System. Theresults show that the Langmuir films of AS-BS have a good response to assemblies of mercury lamp light.The current can be increased by three orders of magnitude. The physical mechanism of photocurrentLangmuir films of AS-BS produced was also discussed.