Dual-Phase Regulation via a Volatile Morphology Director Enables Trap-Suppressed Organic Solar Cells with 20.6%...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) face efficiency limitations due to trap densities from donor and acceptor phase issues.
• Current strategies primarily address acceptor regulation, neglecting synergistic donor-acceptor co-modulation for trap suppression.

Purpose of the Study:

• To introduce 1,3-dibromo-5-iodobenzene (DBI) as a volatile solid additive for simultaneous donor and acceptor phase optimization in OSCs.
• To investigate the mechanism of DBI in mitigating trap densities and enhancing device performance.

Main Methods:

• Coarse-grained molecular dynamic simulations to model phase behavior.
• In-situ synchronic spectroscopy and transient optoelectronic characterizations.
• Fabrication and testing of organic solar cell devices with and without DBI.

Main Results:

• DBI selectively binds to PM6, strengthening interchain interactions and promoting pre-aggregation.
• This PM6 matrix optimization sterically hinders Y6 aggregation, leading to well-defined phase separation.
• DBI treatment improved PCEs from 17.0% to 18.4% in PM6:Y6 devices and achieved 20.6% in a ternary system.

Conclusions:

• DBI effectively suppresses energetic disorder and trap density through synergistic donor-acceptor phase co-modulation.
• The strategy demonstrates significant potential for boosting OSC performance and operational stability.