Selenium-Substituted Nonfused Ring Acceptors: Theoretical Insights into Optoelectronic Properties via Noncovalent...

Area of Science:

• Materials Science
• Organic Electronics
• Computational Chemistry

Background:

• Selenium substitution is a key strategy to tune electronic structures and optoelectronic properties of materials.
• Nonfused ring electron acceptors (NFREAs) are crucial components in organic solar cells.
• Understanding structure-property relationships in NFREAs is vital for device optimization.

Purpose of the Study:

• To systematically investigate the impact of sulfur-to-selenium substitution on the performance of a high-performance NFREA (2BTh-2F).
• To design and characterize novel selenium-containing NFREAs using computational methods.
• To identify promising NFREA candidates for efficient organic solar cells.

Main Methods:

• Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations were employed.
• Nine novel NFREAs with varying selenium substitutions were designed and analyzed.
• Atoms in Molecules (AIM) and Reduced Density Gradient (RDG) analyses were used to study noncovalent interactions.

Main Results:

• Selenium substitution optimized electrostatic potential, frontier molecular orbital levels, and excited-state properties.
• Enhanced Se···O noncovalent interactions were observed, although planarity was maintained by side chains.
• The symmetrical Se-substituted derivative Z5 exhibited the minimum band gap and energy loss, with maximum open-circuit voltage and fill factor.

Conclusions:

• Rational selenium substitution strategies can effectively enhance NFREA performance.
• The designed NFREAs, particularly Z5, offer promising avenues for developing high-performance organic solar cells.
• This study provides critical guidelines for the rational design of next-generation NFREAs.