Novel D-π-A phenothiazine and dibenzofuran organic dyes with simple structures for efficient dye-sensitized solar cells

Abstract

Synthesis of organic molecules is imperative for users to gain a low-cost sensitizer for the purpose of dye-sensitized solar cells (DSSCs). Phenothiazine and Dibenzofuran based organic dyes ((5-(10H-phenothiazin-2-yl) thiophene-2-carbaldehyde and (Z)-2-cyano-N'-((5-(dibenzo[b,d]furan-4-yl)thiophen-2-yl)methylene) acetohydrazide)) are synthesized and optimized as sensitizers for DSSC applications. The synthetic dye compounds are characterized by Mass, FT-IR, NMR and absorption spectra. The molecular energy levels of the PTCH and BFCH were determined using cyclic voltammetry to assess the driving forces for electron injection, redox behavior and regeneration of the dye. The experimental spectral frequencies of the dye molecules are compared to the calculated results. Furthermore, its electronic and photovoltaic properties have been evaluated using Time Dependent-Density Functional Theory (TD-DFT) method. Effects of the acceptor unit (cyanoacetohydrazide), π-conjugation bridges, phenothiazine and dibenzofuran (Donor) were studied. Quantum chemical parameters have also been analyzed using density functional theory. In addition, an important analysis of the reorganization energy, molecular electrostatic potential and the natural bond orbital had also been studied for the title molecules.