Facile and eco-friendly PVA nanocomposites as a photo-luminescent: Anti-counterfeiting, LED and wettability applications

Abstract

Novel MoO3:Eu3+ nanopowder (NP) were synthesised by the propellant chemical route. Polymer nanocomposites (PNCs) were prepared by embedding NPs effectively into the mixture of Poly vinyl alcohol (PVA) and Chitosan solution through the solution casting technique (SCT). This process was extensively used owing to certain benefits such as uniform dispersion of NPs and easiness of the process. Eu3+ doped MoO3 (2–5 wt %) nanocomposites (NCs) were fabricated. Powder X-ray diffraction analysis indicated single orthorhombic crystal structure of the synthesised NCs and confirmed the integration of the nanophosphor into the polymer blend. Crystallite size was estimated to be ∼17nm using Scherrer's formula. The Fourier transform infrared spectrometer technique was employed to reveal the vibrational bands as well as the intermolecular bonding between the polymer blend and MoO3:Eu3+ NPs. Thermogravemetric analysis showed the enhanced thermal stability of the PNCs with the incorporation of NPs. The nature of electronic transitions was studied by optical bandgap energy from Tauc's relation. The photoluminescence emission spectra were monitored at excitation wavelength of 394 nm and noticed the transitions at wavelengths of 599 nm, 613 nm, 630 nm, 652 nm, and 694 nm belongs to the intense orange-red emissions. The emission colour of the NC films was confirmed by CIE chromaticity diagram. Especially, the NCs complex not only can be uniformly dispersed in the monomer solution and can be acted as both the coordination crosslinking agent and luminophores. Besides, upon the incorporation of Eu3+ into the polymer matrix comprising ammonium group, the adhesive strength as well as the mechanical behaviour of the hydrogel are considerably enhanced. The Eu3+ doped NCs that were developed have a great potential for fabricating efficient optoelectronic devices and luminescent hydrogels. This mechanism was further validated and utilised for application in relief printing and screen printing.