Design, Synthesis And Study Of Ambipolar Triphenodioxazine Derivatives

Organic semiconductors have long become the research hotpot with the characteristic of a great variety, easy to be film, obtained by the large number of chemical reactions and so on. Studying the molecule structure, designing innovative, high-mobility materials and optimizing of device performance has gradually become the important challenges of this industry. Compared to conventional double hetero-junction, formed by the electron donor and electron acceptor interspersed network-"bulk hetero-junction"-provides a larger surface for the exciton separation. However, due to the dominant influence of the overall morphology of the composite, multi-component systems such as BHJs are particularly challenging. In this paper, we design three ambipolar triphenodioxazine derivatives, test their spectrum, electrochemistry, thermal stability and make them into bulk hetero-junction solar cell devices to study their performance.First, with carbazole as starting material, through connecting the alkyl chain, nitration, reduction, coupled with chloranil, and closed-loop, the triphenodioxazine derivative A6is synthesized. Next, with dibromobiphenyl as starting material, through nitration, closed-loop, connecting the alkyl chain, nitration, methoxylated, demethylation, reduction with stannous chloride, coupled closed-loop, the dibromo-derivative B8is synthesized. Finally, the same as above basic steps, with catalytic hydrogenation reduction, the not halogen-substituted derivative C2is synthesized. To compensate the triphenodioxazine derivatives’poor solubility, we choose the branched alkyl group of20carbons as the solubilizing group, so that the target compounds can be solvent processing.By spectrum test, the maximum absorption wavelength of the three compounds ais respectively610nm,578nm,581nm with a wide range about500-650nm of strong absorb of light. The effect of the solid film is superior to the solution, and especially compound B8is redshifted22nm, far more than the other two compounds. By cyclic voltammetery curves, the three compounds are ambipolar organic semiconductors, that they can transfer electron, and also can transfer hole. They have two reversible reduction peaks, a reversible oxidation peak and one or two irreversible oxidation peaks. And with good thermal stability, high temperature can’t decompose them. Made into bulk-heterojunction solar cells with PCBM, further study of the relationship between molecule structure and device performance is proceeded by changing ratio, thickness of active layer, annealing temperature and so on.