Synthesis Of Chromophores With Azobenzene As Conjugated Bridge

With the rapid development of optical communications, optoelectronics and optical information processing and other practical fields, NLO materials have become one of the central issues in the field of high technology. Organic NLO materials have attracted much more attention due to their better performance than that of inorganic materials.In this thesis, the recent progress of organic NLO materials was reviewed, and the design theories of organic NLO molecular were systematically introduced, based on which 8 novel chromophores with one-dimensional and two-dimensional structure containing benzene or azobenzene as conjugating bridges were designed and synthesized. The synthesized chromophores and intermediates were characterized by FT-IR spectra, 1H-NMR and elementary analysis. And thermal and optical properties of these chromophores were studied via thermal gravimetric analysis and UV-visible spectrum.TGA indicate that the chromophore with two-dimensional structure containing single benzene as conjugated bridge had better thermal stability. The chromophores with azobenzenes conjugated bridge, compared to one-dimensional structure, thermal stability of two-dimensional structure of the chromophore decreased slightly. But the 8 chromophores all exhibited good thermal stability, of which 5% weight loss temperature was 227 to 294℃. These meet the processing and working temperature requirements of the device.UV-Vis results showed that the introduction of azobenzene to conjugated bridge would make the maximum absorption wavelength(λmax) of chromophores generally red-shift, while the two-dimensional structure made the λmax varying degrees of blue-shift. Especially λmax of chromophore bis-MFC had a blue-shift large as 100 nm when compared to chromophore MFC. In DMSO, the synthesized 8 novel chromophores showed good light transmission, of which the maximum λmax was just reach 545 nm.The NLO properties of the chromophores were measured by solvatochromism method at the wavelength of 1064 nm. The relationship between the nonlinear optical properties and molecular structure of chromophores was studied. The 7 chromophores exhibited good nonlinear optical properties, in which the chromophores containing azobenzene as conjugated bridge with two-dimensional structure possess high μgβ(1064) value. The μgβ(1064) of chromophore bis-MFNC is 259770×10-48 esu, which is an order of magnitude larger than the one-dimension chromophore MFNC.