Charge-Driven Fluorescence Blinking in Carbon Nanodots.

Area of Science:

• Nanotechnology
• Materials Science
• Photophysics

Background:

• Carbon nanodots (CNDs) are promising nanomaterials for various applications.
• Understanding their photoluminescence properties, particularly fluorescence blinking, is crucial for their development.
• The blinking mechanism of CNDs remains less understood compared to semiconductor quantum dots.

Purpose of the Study:

• To elucidate the underlying mechanism of fluorescence blinking in single carbon nanodots.
• To compare the blinking behavior of CNDs with that of semiconductor quantum dots.
• To identify the key processes governing the on and off states of CND emission.

Main Methods:

• Single-particle fluorescence spectroscopy was employed.
• Experiments were conducted at both room and cryogenic temperatures.
• Analysis of temporal fluorescence intensity fluctuations was performed.

Main Results:

• Carbon nanodot blinking exhibits significant similarities to semiconductor quantum dots.
• The temporal blinking behavior of CNDs follows a power law at different temperatures.
• Static quenching via Dexter-type electron transfer is implicated in the transition to off/gray states.
• Electron tunneling from the nanoparticle core governs the transition back to the on state.

Conclusions:

• The study reveals a detailed mechanism for carbon nanodot fluorescence blinking.
• Findings suggest a dual mechanism involving surface group interactions and core electron tunneling.
• This enhanced understanding is vital for optimizing CNDs in fluorescence imaging and other applications.