Ultraweak light-modulated heterostructure with bidirectional photoresponse for static and dynamic image perception

Area of Science:

• Optoelectronics
• Neuromorphic Engineering
• Materials Science

Background:

• Human visual system adaptability inspires optoelectronic neuromorphic devices.
• Bidirectional photoresponse is crucial but often requires high voltages/intensities.
• Existing devices face limitations in low-light and low-voltage operation.

Purpose of the Study:

• To develop a bidirectional ZnO/CsPbBr3 heterostructure neuromorphic image sensor array.
• To achieve ultraweak light stimulation and mimic synaptic functions.
• To enable low-voltage, real-time image processing.

Main Methods:

• Fabrication of a 10x10 pixel ZnO/CsPbBr3 heterostructure array.
• Utilizing ionization/deionization of oxygen vacancies for positive/negative photoconductivity.
• Testing synaptic weight updates under varying green and UV light intensities (45 nW/cm² to 15.69 mW/cm²).

Main Results:

• Demonstrated bidirectional photoresponse at a low bias voltage of 2.0 V.
• Successfully mimicked synaptic functions and visual adaptation.
• Achieved high accuracy in image pre-processing tasks: 92% in pattern recognition and 100% in motion clustering.

Conclusions:

• The proposed heterostructure enables efficient neuromorphic image sensing under ultraweak light.
• The strategy is extendable to other ZnO/perovskite and IGZO/perovskite systems.
• Highlights potential for intelligent visual systems in low-voltage, dark conditions.