Synthesis of MD‐1‐2 co‐sensitizers for 10.35% efficient acid–base pairing with N3 in DSSCs

This work presents a comprehensive investigation of novel organic dyes MD‐1‐2 as active acid and base co‐sensitizers in dye‐sensitized solar cells (DSSCs), using well‐known Ru(II)‐based N3 dyes. These co‐sensitizers contain a triphenylamine ring as a donor scaffold linked with an electron‐withdrawing cyanopyridyl and cyano benzoic acid acceptor for MD‐1‐2. In this study, we demonstrated the significant impact of base dyes with pyridine anchoring units on the photovoltaic parameters of N3‐sensitized devices. This methodology takes advantage of the ability of carboxyl and pyridyl moieties to interact with the Brønsted acid and Lewis acid sites on TiO2 surfaces, respectively. By reducing competition between dyes for surface binding, dye packing density on the TiO2 is enhanced while electron recombination is minimized, leading to higher photovoltage. Furthermore, the influence of varying sensitizer/co‐sensitizer ratios was comprehensively studied. Outcomes showed devices made using co‐sensitizer MD‐1‐2 with sensitizer N3 at all relative concentrations surpassed those with only N3. Importantly, the co‐sensitized devices that were made utilizing 0.3 mM acid–base MD‐1 and N3 sensitizer had the greatest solar energy capacity. It had a power conversion efficiency of 10.35%, a short‐circuit current density of 20.01 mA·cm−2, and an open‐circuit voltage of 752 mV. The results provide fresh insight into optimizing devices to create DSSCs with improved efficiency by choosing acceptable co‐sensitizers at suitable concentrations. Novel acid–base co‐sensitizers MD‐1‐2 were synthesized and combined with N3 dye in DSSCs. Co‐sensitization enhanced light harvesting and suppressed charge recombination. Acid–base pairing of N3 and MD‐1 gave highest power conversion efficiency of 10.35%. Molar ratio of co‐sensitizers significantly impacted photovoltaic performance. DFT calculations provided insights on geometry, electronic properties, and charge transfer.