Luminescence properties of silk cocoon derived carbonaceous fluorescent nanoparticles/PVA hybrid film

Carbonaceous fluorescent nanoparticles (CFNs) with broad particle distribution were synthesized by thermal-treatment using carbonation of silk cocoon as raw materials. The experimental results showed tunable emission wavelength of the nanoparticles. The quantum yield of the CFNs was calculated to be 23%. A CFNs/PVA hybrid thin film was prepared from a blend of the CFNs with polyvinyl alcohol (PVA) showing interesting green afterglow which could be observed by naked eyes. The afterglow spectrum revealed that the CFNs/PVA thin film had a broad afterglow emission peak located at 520 nm. The afterglow intensity decay curve of the film showed visually recognizable period longer than 140 s. The PVA-PVA hydrogen bonding in the PVA matrix may play a key role for the afterglow. (C) 2014 Elsevier B.V.. All rights reserved.