Retina-inspired organic neuromorphic vision sensor with polarity modulation for decoding light information.

Area of Science:

• Materials Science
• Electronics
• Optoelectronics

Background:

• Neuromorphic vision sensors (NeuVS) based on organic field-effect transistors (OFETs) utilize polar functional groups (PFGs) in polymer dielectrics to control charge carriers.
• The precise mechanism by which PFGs modulate charge transport in these devices remains unclear.

Purpose of the Study:

• To investigate the mechanism of charge transport modulation using PFGs in OFET-based NeuVS.
• To enhance the performance of NeuVS devices through the strategic incorporation of specific functional groups into polymer dielectrics.

Main Methods:

• Introduction of carboxyl groups into polymer dielectrics for OFET-based NeuVS fabrication.
• Characterization of charge carrier transport properties and device mobility.
• Evaluation of optical figures of merit and image sensing capabilities, including grayscale signal detection and memory functions.

Main Results:

• Carboxyl groups induce charge transfer at semiconductor/dielectric interfaces, enabling effective carrier transport.
• Achieved device mobility up to 20 cm² V⁻¹ s⁻¹ at a low operating voltage of -1 V.
• Polarity modulation by carboxyl groups increased optical figures of merit by over an order of magnitude compared to carboxyl group-free dielectrics.
• Demonstrated improved image sensing with 52 grayscale signals and memory capabilities at a low power consumption of 1.25 fJ/spike.

Conclusions:

• The study elucidates the role of carboxyl groups in enhancing charge transport and performance in OFET-based NeuVS.
• Findings provide insights for designing high-performance polymer dielectrics for advanced neuromorphic vision applications.
• The developed NeuVS exhibits excellent potential for low-power, high-fidelity image sensing and information decoding.