Promising red emission from functionalized multi walled carbon nanotubes embedded co-doped Bi3++Eu3+: PVA polymer nanocomposites for photonic applications

A bright novel sensitized red emission has been obtained from functionalized multiwalled carbon nanotubes (f-MWCNTs) embedded Bi3++Eu3+: PVA polymer nanocomposites under UV excitation. We have successfully synthesized Eu3+: PVA, Bi3++Eu3+: PVA and Bi3++Eu3++ functionalized MWCNTs: PVA polymer films by traditional solution casting method. The structural and ion-polymer interaction studies have been analysed from XRD and FTIR spectral profiles. Eu3+ doped at different concentrations in PVA polymer films has displayed a red emission at 619 nm (5D0→7F2) under 396 nm (7F0→5L6) of excitation. Upon co-doping with Bi3+ ions in different concentrations to the Eu3+: PVA polymer film, it exhibits enriched red emission than single Eu3+: PVA under the same excitation due to energy migration from Bi3+ to Eu3+. Successful emission photons of Bi3+ ions are collectively absorbed by the Eu3+ ions which lead the improvement of red emission. In the same fashion, enriched red emission is observed from f-MWCNTs impregnated co-doped Bi3++Eu3+: PVA polymer composites. The red emission of Eu3+ is significantly enhanced in two ways through an efficient energy migration process from Bi3+ to Eu3+ and f-MWCNTs to Eu3+. Possible energy transfer mechanism is clearly demonstrated by several fluorescent methods. From these results, these f-MWCNTs embedded Bi3++Eu3+: PVA polymer films might be recommended as promising candidates for red luminescent materials for photonic devices.