New pyran dyes for dye-sensitized solar cells

Although ruthenium-based dyes have been extensively used in dye-sensitized solar cells (DSSCs) as photosensitizers, they have several shortcomings such as high costs and potential environmental toxicities. This has stimulated the development of highly efficient organic dyes as photosensitizers. We report the synthesis and photophysical, electrochemical and theoretical properties of novel pyran-based organic dyes (D1, D2, and D3) as well as their applications in DSSCs for the first time. The designed dyes possess a cyanoacrylic acid group as an acceptor and arylamine group as a donor group in a D-π-A configuration. The introduction of varying donor groups resulted in correspondingly different photophysical and electrochemical properties. The DSSCs fabricated using dye D1 showed the highest photovoltaic performance: a maximum incident photon-to-current conversion efficiency (IPCE) of 42%, a short-circuit current density (Jsc) of 4.76 mA cm−2, an open circuit voltage (Voc) of 0.68 V, and a fill factor (FF) of 0.67, corresponding to an overall conversion efficiency of 2.17% under 100 mW cm−2 irradiation. The synthesized dyes with a pyran chromophore and arylamine donor groups showed potentials for applications in DSSCs.