Electrically Pumped White-Light-Emitting Diodes Based on Histidine-Doped MoS₂ Quantum Dots

Area of Science:

• Materials Science
• Optoelectronics
• Nanotechnology

Background:

• Transition metal dichalcogenides, like Molybdenum disulfide (MoS2), are promising for optoelectronic applications.
• Quantum dots (QDs) offer tunable optical properties but often face challenges with efficiency and stability.
• Developing efficient and stable white-light-emitting diodes (WLEDs) is crucial for next-generation lighting and display technologies.

Purpose of the Study:

• To design, fabricate, and demonstrate novel white-light-emitting diodes (QD-WLEDs) utilizing Molybdenum disulfide quantum dots (MoS2 QDs).
• To investigate the impact of histidine doping on the photoluminescence and electroluminescence properties of MoS2 QDs.
• To evaluate the potential of these histidine-doped MoS2 QD-WLEDs as a low-toxicity alternative for optoelectronic devices.

Main Methods:

• Synthesis of highly luminescent, histidine-doped MoS2 QDs via microwave-induced fragmentation of 2D MoS2 nanoflakes.
• Fabrication of quantum dot white-light-emitting diodes (QD-WLEDs) using the synthesized histidine-doped MoS2 QDs.
• Characterization of photoluminescence (PL) and electroluminescence (EL) spectra, including excitation-wavelength dependence and chromaticity coordinates.

Main Results:

• Histidine-doped MoS2 QDs exhibited a sevenfold increase in emission intensity compared to pristine MoS2 QDs, attributed to nitrogen acceptor bound excitons and defect passivation.
• The fabricated QD-WLEDs demonstrated electroluminescence spectra consistent with PL spectra, with a main peak around 500 nm.
• Stable, broadband white-light emission was achieved with Commission Internationale de l'Eclairage chromaticity coordinates of (0.30, 0.36).

Conclusions:

• Histidine doping is an effective strategy to significantly enhance the luminescence efficiency and stability of MoS2 QDs for WLED applications.
• The developed QD-WLEDs, based on a single light-emitting material, offer unprecedented performance and low toxicity.
• These findings position histidine-doped MoS2 QDs as a promising candidate for next-generation optoelectronic devices, particularly in lighting and displays.