Tailoring the Interfacial Composition of Heterostructure InP Quantum Dots for Efficient Electroluminescent Devices

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Core-shell quantum dots (QDs) with type-I band alignment are crucial for light-emitting applications due to exciton confinement.
• The atomic composition at the core-shell interface critically impacts QD optical and electrical properties.
• For InP cores, limited II-VI shell materials cause interfacial misfit and charge imbalance.

Purpose of the Study:

• Investigate the effect of interfacial stoichiometry on the optical and electrical properties of InP core-shell QDs.
• Develop a method to mitigate interfacial misfit and charge imbalance in InP/ZnSe QDs.
• Enhance the performance of quantum dot light-emitting devices.

Main Methods:

• Employed a direct selenium (Se) injection strategy during InP core synthesis.
• Regulated interfacial chemical composition to form an InZnSe alloy layer.
• Synthesized InP/InZnSe/ZnSe core-shell quantum dots.

Main Results:

• Achieved a high photoluminescence quantum yield (PLQY) of 95% with a narrow emission bandwidth of 34 nm.
• The InZnSe interlayer reduced misfit and mitigated charge imbalance at the core-shell heterojunction.
• Demonstrated a green-emitting electroluminescence (EL) device with high luminance (26370 cd m⁻²) and current efficiency (31.5 cd A⁻¹).

Conclusions:

• Interfacial engineering with an InZnSe alloy layer significantly improves the optical and electrical properties of InP/ZnSe core-shell QDs.
• The developed strategy enhances charge injection efficiency and reduces charge imbalance in EL devices.
• This approach offers a promising pathway for high-performance quantum dot-based optoelectronic applications.