Heteroatom Engineering of Nonfused Ring Electron Acceptors: Design Strategy for Optoelectronic Enhancement

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Nonfused ring electron acceptors (NFREAs) are crucial for high-efficiency organic solar cells (OSCs).
• Current NFREA development faces limitations in performance and understanding structure-property relationships.
• Existing NFREAs achieve up to 19% power conversion efficiency (PCE).

Purpose of the Study:

• To systematically design and model novel NFREAs based on a state-of-the-art structure.
• To investigate the impact of heteroatom substitutions on NFREA optoelectronic properties.
• To provide insights into structure-property relationships for designing high-performance NFREAs.

Main Methods:

• Density Functional Theory (DFT) and Time-Dependent DFT (TDDFT) calculations were employed.
• Six novel NFREA derivatives were designed via heteroatom substitutions.
• Ground- and excited-state properties were systematically investigated.

Main Results:

• Modified NFREAs showed improved molecular planarity, optical gap, and exciton binding energy (Eb) compared to the parent compound.
• Oxygen substitution in the core unit led to reduced Eb, upshifted LUMO energy, and a narrowed HOMO-LUMO gap.
• Calculations indicated enhanced average electrostatic potential in oxygen-substituted derivatives.

Conclusions:

• The designed NFREAs exhibit promising optoelectronic properties for OSC applications.
• Heteroatom substitution, particularly oxygen, offers a viable strategy for NFREA performance enhancement.
• Findings provide crucial guidelines for the rational design of next-generation NFREAs.