Photoluminescence enhancement after thermal treatment of cellulose from different sources

The use of organic materials in optics/photonics is highly attractive due to its promising applications in bioimaging, optoelectronic devices, photonic pigments, etc. However, the absence of π units in polysaccharides like cellulose or chitosan represents a disadvantage as these aromatic rings or double bonds are crucial to reduce non-radiative transitions in organic materials. To our knowledge, the mechanism to achieve photoluminescence (PL) in carbohydrate polymers without π units yet to be studied. Herein, we studied the effect of the drying of cellulose samples on PL, analyzing the effect of a thermal treatment by FTIR and UV-Vis. On one hand, the dominant wavelength of all PL spectra is at 520 nm, all samples show an increment in maximum intensity of PL between 29 and 49