Thermally Stable Quantum Rods, Covering Full Visible Range for Display and Lighting Application

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Quantum rods (QRs) show promise for displays and lighting due to high light out-coupling and polarized emission.
• Synthesizing high-quality green and blue QRs remains challenging, often involving toxic cadmium.
• Regulatory restrictions (RoHS) limit cadmium content in consumer electronics.

Purpose of the Study:

• To develop low-cadmium core-shell quantum rods (QRs) with tunable luminescence across the visible spectrum.
• To evaluate the performance of these QRs in on-chip LED applications.
• To address the challenges of synthesizing green/blue QRs and reduce cadmium toxicity.

Main Methods:

• A one-pot, post-synthetic method was employed to create core-shell QRs.
• Cadmium (Cd) was replaced with zinc (Zn) to reduce toxicity.
• The photoluminescence properties and thermal stability of the synthesized QRs were investigated.

Main Results:

• Low-cadmium QRs with narrow-band luminescence tunable across the visible spectrum were successfully synthesized.
• The QRs exhibited good thermal stability of photoluminescence.
• On-chip LEDs fabricated with these QRs achieved high brightness (120000 nits), wide color gamut (122% NTSC), and high luminous efficiency (115 lm W⁻¹).

Conclusions:

• The developed low-Cd QRs are viable alternatives for display backlighting and general lighting applications.
• This work overcomes synthesis challenges for green/blue QRs and reduces reliance on toxic cadmium.
• The high performance of the QRs demonstrates their potential for next-generation optoelectronic devices.