Low-Bandgap Acceptor Design with π-Bridge Insertion for High-Responsivity NIR Organic Photodiodes
발표자
이맹강 (충남대학교)
연구책임자
이재원 (충남대학교)
초록
내용
We developed π-bridge engineered nonfullerene acceptors (NFAs) for high-specific-detectivity organic photodiodes (OPDs) working beyond 1200 nm in the near-infrared (NIR) range. Prior studies rarely explored how π-bridge design affects NFA-based OPDs. We systematically studied how π-bridge substitution impacts intramolecular charge transfer (ICT), energy levels, and aggregation. Three NFAs were synthesized, tuning the bandgap from 1.12 eV to 1.05 eV and broadening NIR absorption. Suppressing aggregation improved exciton dissociation and reduced nonradiative recombination. The optimized OPD shows a detectivity of 3.43 × 10¹¹ Jones and a –3 dB cutoff frequency of 58.6 kHz at 1050 nm under –2 V. Finally, the device was applied in photoplethysmography (PPG) and optical wireless communication, showing strong potential for biosignal monitoring and transmission.