Near Infrared Light-Emitting Diodes Based on Colloidal InAs/ZnSe Core/Thick-Shell Quantum Dots

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Heavy-metal-free III-V colloidal quantum dots (QDs) are promising for optoelectronics.
• Indium Arsenide (InAs) QDs offer excellent near-infrared absorption and emission.
• Recent advancements achieved 70% photoluminescence quantum yield in InAs QDs with a ZnSe shell.

Purpose of the Study:

• To fabricate and characterize light-emitting diodes (LEDs) using InAs/ZnSe QDs.
• To evaluate the optoelectronic performance and emission properties of these novel LEDs.
• To demonstrate a sustainable and efficient synthesis route for InAs QDs.

Main Methods:

• Fabrication of InAs/ZnSe quantum dot light-emitting diodes (LEDs).
• Characterization of LED performance, including external quantum efficiency (EQE), turn-on voltage, and radiance.
• Analysis of emission intensity versus current density to assess dynamic range and passivation effects.
• Synthesis of InAs QDs using a non-pyrophoric precursor, tris(dimethylamino)-arsine.

Main Results:

• Fabricated InAs/ZnSe QD LEDs achieved 13.3% EQE, a 1.5V turn-on voltage, and 12 Wsr^-1m^-2 maximum radiance.
• LEDs demonstrated an extensive emission dynamic range with a linear correlation between intensity and current density.
• Performance is comparable to state-of-the-art lead sulfide (PbS) QD LEDs.
• The thick ZnSe shell provided efficient passivation, contributing to the observed performance.

Conclusions:

• Heavy-metal-free InAs/ZnSe QD LEDs offer competitive optoelectronic performance in the near-infrared spectrum.
• The developed synthesis route is cost-effective, safe, and environmentally compliant (RoHS).
• These findings position InAs/ZnSe QDs as a viable alternative for next-generation optoelectronic devices.