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

Abstract Oxygen (O 2 )-sensitive probes encapsulated in a polymeric matrix have gas sensitivity improved by adding different metal oxide semiconductors (MOSs) to the composition. In this research, O 2 -sensitive tris(2,2′-bipyridyl) ruthenium(II) chloride ([Ru(bpy) 3 ]Cl 2 ) was chosen as a fluorophore, and SnO 2 and Ni:SnO 2 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% [O 2 ]. 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:SnO 2 -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 O 2 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 O 2 -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.