Metal-free azo dyes anchored on CdS nanowires: Subtle solar cell exploration through experimental and DFT studies

Herein, as-synthesized azo dye (E)-2-isopropyl-5-methyl-4-((4-(4-nitrophenyl) thiazol-2-yl) diazenyl) phenol (D2) has been anchored on a high surface area one dimensional CdS nanowires (NWs) in thin film form. CdS nanowires have been grown through Cd(OH)2 template formation followed by conversion to CdS by ionexchange route. The light-electricity conversion efficiency of the CdS-Azo dye-based solar cell has shown about 5-fold remarkable surge (0.159%) compared to the bare CdS (0.03%) with I3-/I- redox mediator under standard AM 1.5 illumination (100 mW cm-2). Albeit, the DFT studies revealed a higher band gap for pristine D2, alluringly it has depicted higher light-electricity conversion efficiency among the fabricated thin film solar cells after sensitization. The relative increase in sensitivity after sensitization is attributable to facile dye regeneration. Furthermore, after the co-sensitization of CdS thin film with equimolar cocktails of as-synthesized dyes and a natural dye Betanin (Bn), less efficiency was depicted ascribable to plausible dye aggregation upon blending.