Enhancing the O2 sensitivity of [Ru(bpy)3]2+ dye by incorporating SnO2 and Ni:SnO2

Abstract

Oxygen (O2)-sensitive probes encapsulated in a polymeric matrix have gas sensitivity improved by adding different metal oxide semiconductors (MOSs) to the composition. In this research, O2-sensitive tris(2,2′-bipyridyl) ruthenium(II) chloride ([Ru(bpy)3]Cl2) was chosen as a fluorophore, and SnO2 and Ni:SnO2 additives were used to enhance the oxygen sensitivity of the dye. While preparing sensing agents as a form of thin film and nanofiber, dye and MOSs powders were immobilized into the polymethylmethacrylate (PMMA) matrix in close proximity to each other. The oxygen-induced intensity measurements, decay time kinetics, and kinetic response were investigated for each of the sensing slides in the concentration range of 0–100% [O2]. Signal decreases in the emission-based intensity values of all MOSs-doped [Ru(bpy)3]2+-based complexes were monitored. Compared with free form, Ni:SnO2-doped [Ru(bpy)3]2+-based nanofiber agents exhibited a 4.03-fold increase in signal change (I0/I) ratio. The nanofiber structure, which allows the sensor slide to have a higher surface/volume ratio, allows O2 gas to penetrate more effectively. This can lead to greater interaction of the gas within the sensor matrix, resulting in more sensitive detection. Higher Stern Volmer (Ksv) values, greater O2 -induced sensing capabilities, more linear spectral measurements over larger concentration ranges, and faster response and recovery times show that MOSs-doped [Ru(bpy)3]2+-based sensing agents make promising candidates as oxygen probes.