Tailoring benzo[α]phenoxazine moiety for efficient photosensitizers in dye sensitized solar cells via the DFT/TD-DFT method†
Abstract
Three benzo[α]phenoxazine-based dyes were designed by tailoring donor (D) and anchoring (A) moiety to benzo[α]phenoxazine template via DFT and TD-DFT method for dye-sensitized solar cell (DSSC) applications. The transformation of basic benzo[α]phenoxazine by incorporating triphenylamine as a donor (D) plus cyanoacrylic/cyanoacetic acid as the anchoring group (A) at selective and reactive sites to produce a typical D–π–A architecture was accomplished by a molecular engineering approach. The benzo[α]phenoxazine scaffold was used as a precursor or π-linker despite the highly explored phenoxazine scaffold to harness more solar radiation and impede the aggregation issues. The designed dyes are endowed with a planar shape, tuneable light-harvesting capacity, efficient intra-molecular charge transfer (ICT), suitable HOMO and LUMO position, and high dipole moment. Among the three modified dyes, M-3 possesses the highest absorbance, up to 892 nm, while M-2 has high light-harvesting efficiency due to the reduced HOMO–LUMO energy gap, high dipole moment, effective adsorption, and compatible non-covalent interactions. Moreover, dye regeneration, injection efficiency, and effective intramolecular charge transportation provided a significant driving force for the operation of DSSC devices. Thus, incorporating D and A groups successfully manipulates π–π stacking and hydrogen bonding interactions in benzo[α]phenoxazine moiety. The positional impact of the D and A groups on the photosensitizer's architecture is fine-tuned with various structural, optoelectrical, chemical, and electrochemical characterizations. Hence, re-functionalizing less explored organic scaffolds to produce efficient DSSC dye by tailoring D and A groups is a new protocol for dye designing before laboratory execution.