Oxygen sensing nanofibers doped with red-emitting Eu(III) complex: Synthesis, characterization, mechanism, and sensing performance

In this paper, we synthesize a novel diamine ligand of PIP and its corresponding Eu(III) complex of Eu(DBM)3PIP, where PIP = 2-phenyl-1H-imidazo[4,5-f][1,10]phenanthroline, and DBM = 1,3-diphenyl-propane-1,3-dione. The UV–Vis absorption spectra, low temperature phosphorescence spectra, energy transfer mechanism, excited state lifetime of Eu(DBM)3PIP, as well as its photoluminescence spectra, are investigated in detail. Data suggest that the emission of Eu(DBM)3PIP is quenchable by molecular oxygen due to the back-energy transfer process. By doping Eu(DBM)3PIP into a polymer matrix of poly(vinylpyrrolidone) (PVP), the oxygen sensing performance of the resulted nanofibrous membrane is investigated. Finally, the 0.6 wt% doped sample exhibits a linear response towards molecular oxygen, with a sensitivity of 3.5 and response/recovery time of 15 s/24 s.