Fine Control of Electron Trapping via Insulating Property Modulation for Enhanced Photomultiplication in Organic Photodetectors
발표자
김서진 (고려대학교)
연구책임자
우한영 (고려대학교)
초록
내용
Photomultiplication-type organic photodetectors (PM-OPDs) achieve EQE >100% via efficient electron trapping. Here, we introduce a strategy to fine-tune trapping by increasing the insulating character of nonfullerene acceptors (NFAs), rather than tuning energy levels. A series of BTP-based NFAs with varied alkyl chains and asymmetry were designed to modulate the insulation/conjugation ratio. Greater insulation led to longer trap lifetimes (up to 581 ms) and higher trap densities (~1.3×10¹⁸ cm⁻³), enhancing band bending, reducing depletion width (~8 nm), and lowering Schottky barrier height (to 0.23 eV). As a result, A-BTP-DT showed a high EQE of 7520% and detectivity of 2.7×10¹³ Jones at –10 V. This work offers a new approach for enhancing PM-OPD performance by structural control of electron trapping without altering LUMO levels.