Investigation of Structure, Optical Properties and Chemical Stability of the Pyridinium Luminophore with High Quantum Yield

Abstract

This study reports on the synthesis and characterization of a new pyridinium luminophore (KL1421). The main properties of the KL1421 have been modeled by quantum chemistry calculations using the B3LYP method. The structure, electronic, and optical properties of the KL1421 have been investigated by 1H NMR, FT-IR, XRPD, diffuse reflectance, and photoluminescence spectroscopy. The stability of the optical signal and application of the KL1421 as a gas sensor for the detection of water, ammonia, and acetic acid vapors were evaluated. Analysis of theoretical and experimental results showed a significant difference in the KL1421 response to the tested vapors. No response to ammonia and water has been observed whereas interaction with acetic acid resulted in the decrease of the photoluminescence intensity. The proposed interaction model reveals that acetic acid was physically adsorbed on the surface of the KL1421 and had no impact on the structure changes of the KL1421. Our findings show that the developed material KL1421 has strong chemical stability, high quantum yield, and low noise-to-signal ratio of the photoluminescence signal. The developed luminophores didn’t show good sensitivity towards the selected target molecules. They can be applied as photoluminescence markers in emerging applications in the atmosphere with a wide range of pH variation.

Keywords: Organic luminophore, photoluminescence, optical sensor, chemical stability, adsorption