Tailored Environment-Friendly Reverse Type-I Colloidal Quantum Dots for a Near-Infrared Optical Synapse and...

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Colloidal quantum dots (QDs) offer tunable bandgaps and solution processability for optoelectronic devices.
• Existing near-infrared (NIR) photodetectors (PDs) often use heavy metals like lead (Pb) and mercury (Hg), posing environmental and health risks.

Purpose of the Study:

• To develop eco-friendly, heavy-metal-free QDs for NIR photodetectors and artificial optoelectronic synapses.
• To enhance the photoresponse range and performance of QDs through copper (Cu) doping.

Main Methods:

• Synthesized eco-friendly reverse type-I ZnSe/InP quantum dots (QDs) doped with copper (Cu).
• Utilized transient absorption spectroscopy to analyze the role of Cu dopant states.
• Fabricated and characterized photodetectors (PDs) and optoelectronic synapses using the synthesized QDs.

Main Results:

• Cu-doped ZnSe/InP QDs exhibited extended photoresponse from visible to NIR regions.
• Cu-doped QD PDs showed significantly enhanced responsivity (70.5 A W⁻¹) and detectivity (2.8 × 10¹¹ Jones) compared to undoped counterparts.
• Demonstrated synapse-like behaviors (STP, LTP, learning-forging-relearning) under NIR illumination.

Conclusions:

• Copper doping effectively enhances the performance of ZnSe/InP QDs for broadband photodetection.
• The developed QDs are suitable for creating eco-friendly optoelectronic devices, including artificial synapses.
• These QD-based devices show promise for simulating artificial visual systems in optical neuromorphic applications.