Synthesis And Optoelectronic Properties Of Novel Azulene-based Organic Semiconductors

Organic semiconductor materials have attracted academic great interests for their applications in organic field-effect transistors(OFETs),organic light emitting diodes(OLEDs),sensors,organic photovoltaic cells(OPVs).In particularly,organic semiconductors,as a core part of OFETs,are progressing extremely rapidly due to their advantages such as their potential in constructing solution processed,low cost,and large-area stretchable electronics.However,some key problems have also remained: the high air-stable n-type organic semiconductors are very limited,and we still lack of knowledge of structure-property relationships.In this thesis,we designed and synthesized a series of azulene-contained novel organic semiconductor molecules,and tuned their energy levels by introducing different substitutional groups,so that we can achieve efficiently carrier transfer,and study organic semiconductor structure-property relationships.Firstly,we designed and synthesized azulene-based anthanthrene conjugated compounds,and studied optical and electronic properties.As compared,we synthesized the other two molecules by introducing different groups contained benzothiophene and naphthalene into VAT Orange 3 at 4,10-position.The molecular planarity was partly expanded and bandgap was decreased.The acid response spectrum of these molecules showed that the azulene-based anthanthrene was different from the other two molecules may due to the unique dipole moment of azulene.The charge transport properties of the three compounds were investigated by single crystal field-effect transistors device.The molecules had a better hole carrier mobility contained azulene.We also designed novel azulene-based D-A-D structural molecule with potential n type transporting properity by optimally synthesized routes.Their optical and DFT calculation have been characterized.Theory calculation demonstrated that target molecule have a good planarity.The LUMO energy level was lower owing to the introduction of electron-withdrawing imide groups and electron mainly distributed among the conjugated skeleton in favor of the electron transfer.The study showed that substitutional groups can change the HOMO-LUMO gaps,and also had a remarkable influence on the optical characteristics.