K. Naveen Kumar

Bright green emission from f-MWCNT embedded co-doped Bi3+ + Tb3+:polyvinyl alcohol polymer nanocomposites for photonic applications

A bright, dazzling green emission has been obtained from functionalized multi walled carbon nanotube (f-MWCNTs)-embedded Bi3+ + Tb3+:PVA polymer nanocomposites under UV excitation. We successfully synthesized Tb3+:PVA, Bi3+ + Tb3+:PVA and Bi3+ + Tb3+ + f-MWCNTs:PVA polymer films by a solution casting method. For these polymer films, their XRD and FTIR spectral profiles were analyzed for structural details and ion–polymer interaction mechanism. Tb3+ doped at different concentrations in PVA polymer films displayed a green emission at 546 nm (5D4 → 7F5) under 370 nm (7F6 → 5L10) excitation. Upon co-doping with Bi3+ in the Tb3+:PVA polymer film, the film exhibits enriched green emission compared to single Tb3+:PVA under 320 nm excitation due to the energy transfer from Bi3+ to Tb3+. Surprisingly, a common excitation band was found at 320 nm for Tb3+, Bi3+ and f-MWCNTs. After dispersion of the f-MWCNTs in the co-doped Bi3++Tb3+:PVA polymer films, the photoluminescence properties were remarkably enhanced, and a prominent green emission was observed at 546 nm. The green emission of Tb3+ is significantly enhanced though an efficient energy transfer process from Bi3+ to Tb3+ and f-MWCNTs to Tb3+. The possible energy transfer mechanism was clearly demonstrated via several fluorescent methods. The energy transfer mechanism was substantiated with fluorescence lifetime decay dynamics. From these results, these f-MWCNTs-embedded Bi3++Tb3+:PVA polymer films could be suggested as promising candidates for green luminescent materials for photonic devices.

Dazzling green emission from graphene oxide nanosheet-embedded co-doped Ce3+ and Tb3+:PVA polymer nanocomposites for photonic applications

Novel dazzling green emission has been obtained from graphene oxide nanosheet-embedded Ce3+ and Tb3+:PVA polymer nanocomposites under UV excitation. We have successfully synthesized Tb3+:PVA, Ce3+ + Tb3+:PVA and Ce3+ + Tb3+ + graphene oxide nanosheet (GO NS):PVA polymer films by the solution casting method. For these polymer films, their XRD and FTIR spectral profiles have been analyzed for structure details and ion–polymer interaction mechanism. Tb3+ doped at different concentrations in the PVA polymer films displayed a green emission at 546 nm (5D4 → 7F5) and under 370 nm (7F6 → 5L10) excitation. Upon co-doping with Ce3+ to the Tb3+:PVA polymer film, it exhibits enriched green emission compared to the single Tb3+:PVA under the same excitation due to energy transfer from Ce3+ to Tb3+. Surprisingly a common excitation band has been found at 370 nm for Tb3+, Ce3+ and the GO NS. After good dispersion of the GO NS in the co-doped Ce3+ + Tb3+:PVA polymer films, the photoluminescence properties are remarkably enhanced and a prominent green emission is observed at 370 nm. The green emission of Tb3+ is significantly enhanced though an efficient energy transfer process from Ce3+ to Tb3+ and the GO NS to Tb3+. A possible energy transfer mechanism is clearly demonstrated by several fluorescence methods and lifetime decay dynamics. From these results, these GO NS-embedded Ce3+ + Tb3+:PVA polymer films could be suggested as promising candidates for green luminescent materials for photonic devices.