Synthesis, computational study and characterization of a 3-{[2,3-diphenylquinoxalin-6-yl]diazenyl}-4-hydroxy-2H-chromen-2-one azo dye for dye-sensitized solar cell applications

A solution-processable 3-{[2,3-diphenylquinoxalin-6-yl]diazenyl}-4-hydroxy-2H-chromen-2-one azo dye was synthesized. Analysis of measured UV-visible absorption spectrum and frontier orbitals computed using simplified time dependent density functional theory (sTDDFT) revealed its suitability for optoelectronic applications. A dye-sensitized solar cell (DSSC) was fabricated using this metal-free organic dye as a sensitizer. The photovoltaic parameters of the cell were studied under simulated AM 1.5 illumination (100 mWcm(-2)). Comparing the photovoltaic data with a DSSC using a different member of the azo family of dyes, open circuit voltage and fill factor of the device studied in this work were found higher by 33 and 104%, respectively. The performance was also compared with the DSSCs fabricated using 49 commercial mordant dyes and open circuit photovoltage of the device studied in this work was found higher. To gain insight into its charge transport, impedance spectroscopy was performed. Impedance spectra were observed both voltage and frequency dependent.