In silico evaluation of chromene-based D-π-A dyes for high-performance dye-sensitised solar cells

Area of Science:

• Materials Science
• Computational Chemistry
• Renewable Energy

Background:

• Dye-sensitized solar cells (DSSCs) are a promising renewable energy technology.
• Developing efficient, metal-free, and low-cost sensitizers is crucial for DSSC advancement.
• Chromene-based dyes offer a versatile scaffold for sensitizer design.

Purpose of the Study:

• To computationally investigate six novel chromene-based dyes for DSSC applications.
• To examine the impact of customized donor and π-bridge structures on dye properties.
• To provide design guidelines for efficient metal-free DSSC sensitizers.

Main Methods:

• Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) were employed for electronic structure calculations.
• Calculations included energy levels, optical absorption, electronic properties, and reorganization energies.
• The CPCM model was used to incorporate solvent effects (dichloromethane).

Main Results:

• All six dyes exhibited favorable energy levels for efficient electron injection and dye regeneration in DSSCs.
• Dyes M2 and M5 showed the narrowest HOMO-LUMO gaps, indicating enhanced intramolecular charge transfer and bathochromic shifts.
• Dye M5 demonstrated the lowest total reorganization energy, suggesting efficient charge redistribution.

Conclusions:

• Rational modification of donor and π-linker units effectively tunes the optoelectronic behavior of chromene-based dyes.
• The studied dyes show potential as efficient, metal-free sensitizers for DSSCs.
• This work provides valuable insights for designing next-generation DSSC materials.