First-principles framework for bifacial dye-sensitized solar cells: electronic structure, optical properties and...

Area of Science:

• Materials Science
• Physical Chemistry
• Computational Chemistry

Background:

• Bifacial dye@TiO2 architectures are promising for enhanced light harvesting in dye-sensitized systems.
• Fundamental electronic and optical properties of these systems are underexplored theoretically.
• A comprehensive first-principles understanding of bifacial dye-semiconductor interfaces is lacking.

Purpose of the Study:

• To systematically investigate the electronic and optical properties of monofacial and bifacial dye@TiO2 systems.
• To analyze the impact of bifacial functionalization on electronic structure, excitation pathways, and optical response.
• To provide a theoretical framework for understanding bifacial effects and guiding future dye design.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Linear-response time-dependent Density Functional Theory (LR-TDDFT) investigations.
• Analysis of three representative organic dyes in monofacial and bifacial configurations.

Main Results:

• Bifaciality is not an inherent dye property but depends on molecular orbital distribution.
• The choice of exchange functional significantly influences the observed bifacial effects.
• Detailed analysis of electronic structure, excitation pathways, and directional optical response was performed.

Conclusions:

• This study establishes the first consistent theoretical framework for interpreting bifacial effects in dye-sensitized architectures.
• Bifaciality is a tunable property influenced by molecular design and computational methodology.
• Provides crucial design principles for optimizing future bifacial dye systems for improved performance.