Non-Fullerene Acceptor-Based Solar Cells: From Structural Design to Interface Charge Separation and Charge Transport.

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Fullerene derivatives face limitations in organic solar cells, including poor light absorption and stability.
• Non-fullerene acceptors (NFAs) offer a promising alternative to overcome these challenges.
• Developing efficient NFAs is key to advancing organic photovoltaic technology.

Purpose of the Study:

• To investigate the electronic and optical properties of two NFAs (IDIC, IDTBR) and five donor polymers.
• To analyze ten donor/acceptor (D/A) interfaces for bulk-heterojunction solar cell applications.
• To compare the performance of IDIC-based versus IDTBR-based interfaces.

Main Methods:

• Quantum-chemical (QM) calculations for electronic and optical properties.
• Construction and investigation of D/A interfaces using QM.
• Application of the Marcus semi-classical model for charge transfer analysis.

Main Results:

• IDTBR exhibits better electron transport and optical absorption than IDIC as single molecules.
• D/A interfaces show enhanced and broadened sunlight absorption spectra compared to individual components.
• IDIC-based interfaces demonstrate superior electron injection, optical properties, and charge separation over IDTBR-based interfaces.

Conclusions:

• IDIC-based interfaces exhibit favorable charge separation rates and low recombination rates, indicating potential for high power conversion efficiencies.
• Polymer/IDIC interfaces are predicted to outperform polymer/IDTBR interfaces in bulk-heterojunction solar cells.
• The study highlights the importance of interface engineering for optimizing NFA-based organic solar cell performance.