Role of carbon quantum dots and film thickness on enhanced UV shielding capability of flexible polymer film containing carbon quantum dots/N-doped ZnO nanoparticles

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>We report a simple method for preparing flexible polymer film containing carbon quantum dots/N-doped ZnO (CQD/N-ZnO) nanoparticles, as UV shielding material. The polymer film showed an enhanced UV shielding capability with increasing of CQD/N-ZnO nanoparticles. The maximum of 47% of UV shielding capability was achieved with 1 wt.% of CQD/N-ZnO nanoparticles and two-order enhancement was achieved by controlling film thickness to 250 μm. It was found that CQDs plays important role to promote compatibility of hydrophilic ZnO into hydrophobic polymer matrix without disturbing the transparency of the film. An excellent UV shielding capability of 85% and 92% was witnessed in 250 μm thick polymer film under a UV lamp and direct daylight, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Free-standing and flexible polymer films were prepared with CQD/N-ZnO nanoparticles. </LI> <LI> Owing to the surface modification by the CQDs, CQD/N-ZnO nanoparticles were able to disperse readily in the polymer matrix. </LI> <LI> High transparency polymer films were obtained due to better dispersion of CQD/N-ZnO nanoparticles. </LI> <LI> The CQDs assist to improve the dispersion N-ZnO in polymer matrix. </LI> <LI> An excellent UV-shielding property, irrespective to different light sources. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>A free-standing and flexible polymer film containing CQD/N-ZnO nanoparticles can be explored as potential candidate as UV light filter. The maximum of ∼92% of UV light was shielded by the 250 μm thick polymer film containing just 1.0% of CQD/N-ZnO nanocomposites, under the direct daylight and the results are consistent with UV lamp source.</P> <P>[DISPLAY OMISSION]</P>