Carbazole Based (D–π–A) Sensitizer: Synthesis, Characterization and its DSSC Application

Görgün K., Yandimoglu M.

European Journal of Science and Technology, vol.41, pp.92-99, 2022 (Peer-Reviewed Journal)


In this work, a new organic carbazole-based donor–π–acceptor (D–π–A) sensitizer, C3, comprising carbazole core as an electron donor, phenyl units as a π-conjugated bridge, and fluoro groups as an electron acceptor, has been synthesized and used for dye at ZnO based dye-sensitized solar cells (DSSCs). 3,6-di(2,4-difluorophenyl)-N-octyl carbazole (C3) was synthesized with halogenation and alkylation reaction and Suzuki-Miyaura cross-coupling reaction with good yields. Synthesized C3 sensitizer was characterized by FT-IR, 1H NMR, and 13C NMR. In addition, the optical (UV-Vis and fluorescence) and thermogravimetric properties of this compound were investigated. The hydrothermally synthesized ZnO nanopowder crystal structure was scrutinized by X-ray diffraction spectroscopy (XRD) and determined to belong to a hexagonal wurtzite structure. Scanning electron microscopy (SEM) images have shown that ZnO nanopowder has a highly dense and uniform leafy-like morphology. ZnO-based DSSC devices were fabricated using C3 and N719. The power conversion efficiencies (PCE) and open circuit photovoltage (Voc) of metal-free organic dye (C3), ruthenium dye (N719) and mixture dye (C3-N719) was measured 0.006% - 0.28 V, 0.461% - 0.44 V and 0.893% - 0.53 V respectively. Because of the increasing efficiency of N719-based DSSCs with C3, it was determined that C3 reduced dye aggregation so it could be used as a co-sensitizer.