| Organic photorefractive (PR) materials have been paid much attention due to easily-adjusted performance of organic PR materials and easy preparation of organic PR devices. The PR performance depends mainly on the photon-generated efficiency and diffusibility of carriers. Therefore, the modification of band gap of photoconductors in PR devices will benefit to the photon-generation of carriers, the formation of internal built-in electric field, and then the improvement of PR performance. Therefore, a series of novel photoconductive materials are prepared as organic photoconductors in PR devices through one donor-alternating-acceptor approach.1、The derivatives of benzothiadiazole and benzotriazole are synthesized as acceptor units with strong electron-withdrawing ability. The derivatives of phenothiazine, carbazole and triphenylamine are also prepared as donor units with great electron-donating ability. Then, novel near-infrared photoconductive micromolecules are synthesized through D-A-D strategy to improve the mismatching of energy levels inside PR devices.2、The UV-vis spectra show that the target compounds with strong electron-withdrawing and electron-donating units have the tunable band gap from2.398eV to2.183eV.3、Target compounds bear good solubility and low Tg with the introduction of appropriate alkyl chains, which will improve their processabilities. The PR performance will potentially be improved owing to the photo-induced orientation-enhanced effect.4、he results of1H-NMR,13C-NMR and IR indicate the chemical structure of synthesized compounds is in accord with the target compounds. The TG and DSC measurements show all the compounds have the decomposition temperature higher than350℃, indicating good thermostability.5.The preliminary research on hyperbranched photoconducting polymers is ongoing in our laboratory with the aim of the further optimization of photoconduction, film-forming, light&heat stability of organic PR devices. |
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