Patterning of pH sensitive fluorescent bipyridazine derivatives

Area of Science:

• Materials Science
• Analytical Chemistry
• Organic Chemistry

Background:

• Development of sensitive and selective pH sensors is crucial for various analytical applications.
• Fluorophore-based sensors offer advantages in sensitivity and real-time monitoring.
• Existing pH sensors may face limitations in stability, sensitivity, or patternability.

Purpose of the Study:

• To explore the potential of a novel piperazine-substituted bipyridazine fluorophore (DPP-BPDZ) as a pH sensor.
• To investigate the sensing performance of DPP-BPDZ in solution and thin film formats.
• To develop a patternable fluorescent film sensor for localized pH detection.

Main Methods:

• Synthesis and characterization of the DPP-BPDZ fluorophore.
• Spectroscopic analysis (fluorescence spectroscopy) to evaluate pH sensitivity in solution.
• Fabrication of thin film sensors using DPP-BPDZ embedded in a PMMA host.
• Development of a patternable sensor by incorporating a photoacid generator (PAG).
• UV-induced patterning of fluorescent patterns on the film sensor.

Main Results:

• DPP-BPDZ exhibits high fluorescence quantum yield (0.63) in solution.
• Fluorescence intensity decreases linearly with increasing acetic acid concentration due to protonation.
• The thin film sensor shows an exponential decrease in fluorescence intensity with decreasing pH.
• Enhanced sensitivity observed below pH 4.5.
• Patternable sensors with 10 µm line width and high contrast were fabricated using UV light and PAG.

Conclusions:

• DPP-BPDZ is a promising pH-sensitive fluorophore for both solution-based and thin-film sensing applications.
• The developed thin film sensor demonstrates effective and sensitive pH detection.
• The integration of PAG enables the creation of patternable fluorescent sensors for advanced applications.