(D - π - A)3 Type metal-free organic dye for dye-sensitized solar cells application

Three novel (D - pi -A)(3) type metal-free organic dyes (PTZTC1 - 3) along with a reference dye (RD - SC) bearing a mono D - pi - A unit, comprising 4-positon substituted phenyl coupled with phenothiazine as a donor, thiophene as a pi-conjugated linker and cyanoacrylic acid as an acceptor, were synthesized. The UV-Vis absorption spectra in solution and on TiO2 film, electrochemical redox potentials, and the photovoltaic parameters including incident monochromatic photon-to-current conversion efficiency (IPCE), short-circuit current (J(sc)), open-circuit voltage (V-oc), maximum power conversion efficiency (eta), and electrochemical impedance spectroscopy (EIS) of the corresponding dye-sensitized solar cells (DSSCs) were further explored. Among the DSSCs fabricated with these dyes, the PTZTC3 sensitized cell showed a eta of 6.09% under standard global AM 1.5 solar condition (100 mW cm(-2)) owing to its relatively higher IPCE, higher J(sc) higher V-oc and longer electron lifetime (tau(r)).