Study On The Liquid Crystalline Properties And Aggregation Of The Charge Transfer Complex Based On Triphenylene Derivative

These compounds 3,6-dicarbethoxy-2,4,10,11-tetrapentyloxy-triphenylen(36TPE), 2,4,7-trinitro-9-fluorenone(TNF), 3,4,9,10-tetra-(5-alkoxycarbonyl)perylenes(C1) 3,4,9,10-tetra-(6-alkoxy-carbonyl)-perylenes(C2) 3,4,9,10-tetra-(7-alkoxycarbonyl)perylenes(C3) and 3,4,9,10-tetra-(8-alkoxycarbonyl)perylenes(C4) were designed and synthesized. 1H-NMR were used to determine the chemical structures. 36 TPE was mixed with donor molecules TNF, 7,7,8,8-Tetracyanoquinodimethane(TCNQ),C1,C2,C3,C4 respectively to form charge transfer complex according to the mole ratio 1:1. The spectroscopic characteristics of these compounds were studied by FT-IR, UV-vis, and Fluorescence spectra. The thermal properties were studied by differential scanning calorimetry(DSC). Polarized light microscopy and one-dimensional wide-angle X-ray diffraction analysis(1D WAXD) were used to examine the phase structures. The ionization potential of these compounds were studied by photoelectron yield spectroscopy(PYS). Time-of-flight(TOF) method was used to investigate the charge carrier mobilities. Results displayed that the color of complex 36TPE/TNF and 36TPE/TCNQ became darker, the phenomenon of fluorescence vanished, and the remarkable CT-band appeared in the UV absorption spectrum, which indicating that the formation of charge-transfer complexes. The UV-vis and FT-IR of 36TPE/C1,36TPE/C2,36TPE/C3 and 36TPE/C4 were only superimposed of each components, indicated that the charge-transfer complexes were not formed. Combined with DSC and POM, the liquid crystalline range of 36 TPE was start from room temperature to the clear point and the crystalline and liquid crystalline phase existed in these compounds C1, C2, C3 and C4. Melting points were elevated after mixing, the liquid crystalline range became narrow, the characteristic focal conic textures appeared after doping. Combined with the result of electron spectrum, UV-Vis spectra, XRD and change carrier mobilities, the columnar stacking was formed in these complex which indicated that the formation of bipolar transmission of electron and hole at room temperature, and the sandwiched model was formed to hinder the transmission of the charge carriers at high temperature. The HOMO value of complex was between the value of donor and acceptor, and that of LUMO was below the value of donor and acceptor. If charge transfer complex was formed, the value of LUMO was lower than the value of donor and acceptor. While if charge transfer complex was not formed, the value LUMO was between the value of donor and acceptor.