Enhanced light harvesting in dye-sensitized solar cells via Triazole π-bridged organic dyes: insights into co-sensitization and efficiency optimization

The optimization of light absorption in dye-sensitized solar cells (DSSCs) represents a significant challenge that is addressed through molecular design strategies, such as the incorporation of strong electron-donating groups and the extension of π-conjugated spacers in donor-spacer-acceptor dye architectures. This research endeavor focused on the synthesis and evaluation of two innovative triazole π-bridged organic dyes, designated as MSA-1 and MSA-2, for their application in DSSCs. The co-sensitization of these dyes with the benchmark dye N719 achieved power conversion efficiencies of 7.65% and 7.53%, respectively. Notably, the MSA-1 dye demonstrated superior short-circuit current density (Jsc of 16.93 mA/cm2 compared to 15.93 mA/cm2 for MSA-2, attributed to its broader light absorption spectrum and enhanced molar extinction coefficient facilitated by the triphenylamine donor. To further boost electron injection efficiency, a novel hole-conductor-acidified co-adsorbent (HC-Acid) was introduced, significantly enhancing the performance of MSA-1 + N719-based DSSCs. The addition of HC-Acid improved Jsc from 16.93 mA/cm2 to 17.98 mA/cm2, culminating in a remarkable power conversion efficiency of 9.50%. In contrast, the integration of HC-Acid with MSA-2 + N719 resulted in a more modest efficiency increase, from 7.53% to 8.96%. These findings highlight the potential of triazole-based organic dyes, particularly when combined with advanced co-sensitization and co-adsorption strategies, for achieving high-performance DSSCs.