Adsorption Promoted Aggregation-Induced Emission Showing Strong Dye Lateral Interactions

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Aggregation-induced emission (AIE) is crucial for fluorescence applications.
• Traditional AIE induction methods include solvent changes, pH, and self-assembly.
• The AIE luminogen 4,4'-(hydrazine-1,2-diylidene bis(methanylylidene)) bis(3-hydroxybenzoic acid) (HDBB) exhibits AIE at low pH but not neutral pH.

Purpose of the Study:

• To explore adsorption-induced aggregation as a novel method for AIE.
• To investigate the use of Y2O3 nanoparticles for inducing AIE in HDBB at neutral pH.
• To understand the interactions governing HDBB adsorption on nanomaterials.

Main Methods:

• Utilized Y2O3 nanoparticles as a non-quenching nanomaterial.
• Investigated HDBB adsorption and fluorescence changes at pH 7.0.
• Employed fluorescence lifetime measurements to confirm HDBB aggregation.
• Compared HDBB adsorption with other dyes (porphyrin, fluorescein, calcein, rhodamine B) and nanomaterials (graphene oxide, CeO2, cationic liposome).

Main Results:

• HDBB showed a sevenfold fluorescence increase upon adsorption onto Y2O3 nanoparticles at pH 7.0.
• Fluorescence lifetime confirmed HDBB aggregation in the presence of Y2O3.
• Adsorption interactions were strong, not following Langmuir isotherms, and sensitive to salt and phosphate.
• Other tested dyes showed quenching or no adsorption, and other nanomaterials had varied effects.

Conclusions:

• Adsorption onto Y2O3 nanoparticles effectively induces AIE in HDBB at neutral pH.
• Electrostatic and metal-binding interactions are critical for HDBB adsorption.
• This study presents a facile approach for AIE dye aggregation and enhanced adsorption.