Theoretical study of high-efficiency organic dyes with the introduction of different auxiliary heterocyclic acceptors based on IQ1 toward dye-sensitized solar cells.

Dye-sensitized solar cells (DSSCs) are currently the most widely developed low-cost photovoltaic devices. A series of D-A-π-A metal-free organic dyes based on IQ1 were designed and theoretically characterized by introducing different auxiliary acceptors. The results show that the introduction of auxiliary heterocyclic acceptors could effectively tune the photoelectronic properties. In addition, all designed dyes exhibit better optoelectronic properties than IQ1. In particular, dye PIAQ not only has excellent light harvesting capability over the entire visible region and a portion of the near-infrared region, wider light harvesting efficiency (LHE) curve and larger maximum short-circuit current density (J), but also has narrower energy gap (HOMO-LUMO), larger shift of the conduction band energy level (ΔE) and lower injection and regeneration driving force. Therefore, the designed sensitizers might have outstanding properties and could be promising candidates for improving DSSCs performance.