Conjugated hole-transport molecules based on triphenylamine and aminoflourene: Synthesis, structural, solvatochromic and electrochemical properties

Azomethine based substances containing triphenylamine and aminoflourene core, (E)-N-(4-(diphenylamino)benzylidene)-9H-fluorene-2-amine ((C18H14N)CH=N(C13H9)) (C1), (E)-N-(4,4'-9H-fluorene-2-amine)phenyl)-N-phenylbenzeneamine ((C13H9)N=CH(C18H13N)CH=N(C13H9)) (C2) have been synthesized for the application in solar cells as hole transport materials. The structure of the compounds C1 and C2 has been confirmed by using FTIR, Mass, H-1 NMR, C-13 NMR spectroscopy and elemental analysis. The optical properties of the compounds have been investigated by using UV-Visible and fluorescence spectroscopy. Bathochromic shift in the emission spectrum of the compounds as a function of solvent polarity was studied in terms of Lippert-Mataga approximation and correlated with theoretical studies. The experimentally observed HOMO and LUMO levels of both compounds were corroborated with the theoretically calculated values which were found to be comparable with the values of existing hole transport materials. (C) 2018 Elsevier B.V. All rights reserved.