Molecular Engineering of Indoline-Based D–A−π–A Organic Sensitizers toward High Efficiency Performance from First-Principles Calculations

Abstract

A series of new D–A−π–A indoline-based metal-free dyes, which are derived from the reported dye WS-9, have been designed and characterized theoretically for application in future dye-sensitized solar cells (DSSCs). The absorption, light harvesting efficiency, kinetics of charge injection, and recombination for all chromophores have been systematically investigated via first-principles calculations. We find that featuring the quinoxaline auxiliary acceptor instead of benzothiadiazole and modification on the −A acceptor (2-cyanoacrylic acid) with the −A1 acceptor (2,3-dicyanoacrylic acid) could result in a positive influence in dye CDQ-A1 with respect to WS-9, which induces a remarkable enhancement of the parameters in close connection with the short-circuit current density (Jsc) as well as the open-circuit photovoltage (Voc). In comparison to another CDQ dye, CDQ-A4, which differs from CDQ-A1 by only the acceptor group, CDQ-A1 displays outstanding performance due to its key parameters (i.e., absorption wavelength, light harvesting efficiency, dipole moment, less electron recombination) to achieve a balance between competing factors.