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

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 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% [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: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 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.