Robust Imaging through Light-Scattering Barriers via Energetically Modulated Multispectral Organic Photodetectors

Area of Science:

• Organic electronics
• Photodetector technology
• Materials science

Background:

• Emerging technologies require low-noise near-infrared (NIR) photodetectors.
• Organic photodetectors (OPDs) offer integration advantages but suffer from high noise.
• Commercialization of OPDs is limited by noise constraints.

Purpose of the Study:

• To demonstrate a bulk heterojunction (BHJ) NIR OPD with ultralow noise.
• To introduce a novel electron-blocking layer (EBL) for noise reduction.
• To explore EBL design principles for enhanced OPD performance.

Main Methods:

• Synthesis of a new electron-blocking layer (EBL): ((2,7-dicyano-9H-fluorene-9,9-diyl)bis(propane-3,1-diyl))bis(phosphonic acid) (3PAFCN).
• Energetic modulative design strategies to optimize interfacial properties and morphology.
• Characterization of OPD noise current and specific detectivity.

Main Results:

• Achieved an ultralow noise current of 2.18 fA in the BHJ NIR OPD.
• Attained a specific detectivity of 2.50 × 10¹⁴ cm Hz^0.5 W^-1 at 808 nm.
• Demonstrated exceptional imaging clarity in low-light and foggy conditions.

Conclusions:

• The novel 3PAFCN EBL significantly reduces noise in NIR OPDs.
• The developed OPDs show great potential for advanced imaging applications.
• EBL design principles are broadly applicable to various photoactive materials.