Enhanced Exciton Delocalization in Organic Near-Infrared Photodetectors via Solid Additive-Mediated J-Aggregation

Area of Science:

• Optoelectronics and Organic Electronics
• Materials Science for Photodetection

Background:

• Near-infrared organic photodetectors (NIR-OPDs) are crucial for health monitoring and night vision.
• Developing self-powered NIR-OPDs requires controlling dark currents, enhancing NIR sensitivity, and optimizing material properties.

Purpose of the Study:

• To introduce a solid additive (DIB) to improve J-aggregation and exciton delocalization in acceptor molecules.
• To broaden the spectral response and enhance detection capabilities of NIR-OPDs.
• To address compatibility challenges in self-powered NIR-OPD development.

Main Methods:

• Utilized a solid additive (DIB) to influence the morphology and intermolecular interactions of acceptor molecules.
• Investigated the electrostatic affinity between the additive and acceptors, controlling π-π stacking.
• Analyzed the impact on exciton delocalization, charge separation, and device performance.

Main Results:

• The solid additive induced orderly face-to-face stacking of acceptors, enhancing intermolecular interactions.
• Achieved delocalization of electron-hole pairs, reduced exciton recombination, and increased charge separation efficiency.
• Modified devices demonstrated specific detectivity exceeding 10^14 Jones from 695-860 nm.

Conclusions:

• The solid additive approach successfully improved NIR-OPD performance by controlling molecular aggregation and electronic properties.
• Established a new benchmark for NIR response in organic photodetection.
• Expanded the potential applications of self-powered NIR-OPDs in various fields.