Novel phenothiazine-based organic dyes with a heteroleptic dual-electron-acceptor for dye-sensitized solar cells

We designed a novel organic dye with a heteroleptic dual-electron acceptor (cyanocrylic acid and rhodanine-acetic acid) on each side of a phenothiazine-based organic dye as a photosensitizer for dye-sensitized solar cells (DSSCs). Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations were used to estimate the photovoltaic properties of the dyes, with the findings showing that the organic dyes when used in the heteroleptic dual-electron-acceptor type resulted in higher performance than their single electron-acceptor and homoleptic dual-electron-acceptor counterparts due to the higher molar extinction coefficients and the orientation of the adsorbed dye. It was attributed to relatively broad and intense absorption spectra in the visible region with the rhodanine-acetic acid moiety and abundant electronic coupling with TiO2 of the cyanoacrylic acid anchoring group.