Reversible Acid-Base Long Persistent Luminescence Switch Based on Amino-Functionalized Metal-Organic Frameworks

Area of Science:

• Materials Science
• Chemistry
• Nanotechnology

Background:

• Long persistent luminescence (LPL) materials offer distinct advantages over short-lived fluorescent materials for applications requiring sustained light emission.
• Metal-organic frameworks (MOFs) are increasingly explored for their tunable properties and potential in luminescence-based technologies.
• Functional LPL MOF materials as probes remain relatively underexplored, highlighting a gap in current research.

Purpose of the Study:

• To synthesize and characterize novel amino-functional LPL MOFs.
• To investigate the photoluminescent properties, including adjustable fluorescence and phosphorescence, of the synthesized MOFs.
• To explore the potential of these MOFs as visual sensors for acids and ammonia, leveraging their LPL switching behavior.

Main Methods:

• Synthesis of two amino-functional LPL MOFs: VB4-2D and VB4-1D.
• Characterization of photoluminescence, including adjustable fluorescence and phosphorescence emission.
• Investigation of acid and ammonia sensitivity through monitoring luminescence intensity changes.
• Evaluation of LPL switching behavior for visual sensing applications.

Main Results:

• Successful synthesis of VB4-2D and VB4-1D MOFs with tunable blue-to-green and cyan-to-green luminescence.
• Observation of bright and adjustable LPL emission upon removal of radiation sources.
• Demonstration of acid and ammonia sensitivity, with reversible luminescence intensity changes.
• Visual discernment of LPL intensity switching, enabling naked-eye detection of volatiles.

Conclusions:

• The synthesized amino-functional LPL MOFs exhibit promising adjustable photoluminescence and LPL switching capabilities.
• These MOFs can serve as visual sensors for acids and ammonia, with reversible and cyclable responses.
• The unique combination of photoluminescence and visual LPL switching offers a novel platform for stimulus-responsive materials, anticounterfeiting, and encryption.