Synthesizing luminescent carbon from condensed tobacco smoke: bio-waste for possible bioimaging

Used cigarette filters, a waste material and a major source of land pollution, were used as raw material to study the nature of condensed tobacco smoke (tar) using microscopy, optical, IR, photoluminescence, and Raman spectroscopy, as well as X-ray diffraction and electron and fluorescence microscopy. The tar present in the cigarette filter bud was used to synthesize luminescent low dimensional carbon using a simple methanol extraction technique. The collected material shows light blue emission under UV excitation with emission peak energy depending strongly on the excitation wavelength. Such excitation energy dependent emission is observed from the extract solution and the dried film. Careful analysis was carried out to understand its origin, which revealed the presence of a giant red-edge effect in the samples. A correlation between room temperature photoluminescence spectroscopy and fluorescence microscopy was carried out. The presence of amorphous phase carbon was established using Raman spectroscopy, and a quantum yield of more than 9% was estimated, which was moderately high in comparison with the one shown by carbon dots prepared by using other sources and can be used for bioimaging applications.