Dual State Emissive AIE Active Carbon Dots with Matrix-Free Room Temperature Phosphorescence

Area of Science:

• Materials Science
• Organic Chemistry
• Optoelectronics

Background:

• Long-lived triplet excitons are crucial for high-efficiency organic light-emitting diodes (OLEDs).
• Achieving matrix-free solid-state emissive room temperature phosphorescence (RTP) from carbon dots (CDs) remains a significant challenge.
• Carbon dots (CDs) offer tunable optical properties but often require matrices for solid-state emission.

Purpose of the Study:

• To synthesize novel carbon dots (CDs) capable of matrix-free solid-state emission and room temperature phosphorescence (RTP).
• To leverage the unique structural properties of (R)-1,1-Bi-2-naphthol (R-Binol) for enhanced photoluminescence.
• To demonstrate the potential of these CDs in optoelectronic applications, such as phosphor-converted light-emitting diodes (pc-LEDs).

Main Methods:

• Synthesis of R-Binol-derived CDs via a facile one-pot solvothermal method.
• In-depth structural characterization using advanced analytical techniques.
• Investigation of photophysical properties, including aggregation-induced emission and RTP in solid state.

Main Results:

• The synthesized CDs exhibit dual emission due to a twisted naphthalene moiety that prevents π-π stacking.
• CD aggregates show a 32-fold enhancement in emission intensity in a THF-water mixture.
• For the first time, matrix-free CDs harvested triplet excitons, achieving a 23% photoluminescence quantum yield (PLQY).
• A functional phosphor-converted light-emitting diode (pc-LED) was successfully fabricated using these CDs.

Conclusions:

• The R-Binol-derived CDs represent a breakthrough in achieving matrix-free solid-state RTP from carbon dots.
• The unique structure of these CDs enables efficient harvesting of triplet excitons for enhanced luminescence.
• These findings pave the way for advanced optoelectronic devices with improved performance and simplified fabrication.