Stable Red-Emission Mixed Halide CsPb(Br/I)₃ Perovskite Quantum Dots for LEDs

Area of Science:

• Materials Science
• Quantum Dot Technology
• Photonic Devices

Background:

• Red-emission mixed-halide CsPb(Br/I)3 perovskite quantum dots (PeQDs) offer tunable optical properties and high color purity for light-emitting diodes (LEDs).
• Surface defects and environmental sensitivity cause nonradiative recombination, leading to low photoluminescence quantum yield (PLQY) and poor stability, hindering practical applications.

Purpose of the Study:

• To address the limitations of CsPb(Br/I)3 PeQDs by improving PLQY and environmental stability.
• To investigate the efficacy of bromotrimethylsilane (TMSBr) as a passivation agent for post-treatment.

Main Methods:

• Post-treatment of CsPb(Br/I)3 PeQDs using bromotrimethylsilane (TMSBr).
• Photoluminescence quantum yield (PLQY) measurements.
• Environmental stability testing (air, UV, thermal stress).
• Density functional theory (DFT) calculations to elucidate passivation mechanisms.

Main Results:

• TMSBr treatment significantly enhanced PLQY from 26.6% to 98.1% by suppressing nonradiative recombination.
• Improved environmental stability of PeQDs against air, UV radiation, and thermal stress due to hydrophobic TMS groups.
• DFT calculations confirmed Br- ions passivate iodide vacancies and TMS groups stabilize undercoordinated I- ions.

Conclusions:

• TMSBr is an effective passivation agent for enhancing the performance and stability of CsPb(Br/I)3 PeQDs.
• The developed passivation strategy offers a simple and efficient route for high-performance, stable PeQD-based devices.
• Fabricated white LEDs demonstrated excellent performance with a high color rendering index (91.6) and luminous efficacy (70.6 lm/W).