Conversion of Photoluminescence Blinking Types in Single Colloidal Quantum Dots
Changgang Yang1, Yang Li2,3, Xiaoqi Hou4
1State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, 030006, China.
Small (Weinheim an Der Bergstrasse, Germany)
|December 27, 2023
Summary
Researchers investigated colloidal quantum dot (QD) photoluminescence blinking. They discovered that blinking behavior in alloyed CdSe/ZnS and perovskite QDs depends on size, shell thickness, and excitation, offering insights for high-quality QD development.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Colloidal quantum dots (QDs) are crucial for luminescence applications but suffer from photoluminescence (PL) blinking.
- Understanding QD blinking mechanisms is key to developing high-quality QDs.
Purpose of the Study:
- To investigate the blinking behavior of various colloidal QDs.
- To elucidate the mechanisms responsible for different blinking types.
Main Methods:
- Studied blinking in colloidal QDs with varying surface ligands, particle sizes, shell thicknesses, and compositions.
- Analyzed single alloyed CdSe/ZnS and perovskite QDs under different excitation conditions.
Main Results:
- Alloyed CdSe/ZnS QDs showed irreversible conversion from Auger-blinking to band-edge carrier (BC-blinking) with shell thickness up to 2 nm.
- Perovskite QDs exhibited reversible conversion between BC-blinking and Auger-blinking, dependent on particle size relative to Bohr diameter.
- Blinking type conversion is attributed to changes in effective trapping sites and altered wavefunction overlap.
Conclusions:
- QD blinking behavior is influenced by surface ligands, particle size, shell thickness, and composition.
- This study clarifies discrepancies in previous QD blinking reports and deepens the understanding of blinking mechanisms.
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