Luminescent cellulose sheet fabricated by facile self-assembly of cadmium selenide nanoparticles on cellulose nanofibres

Abstract

A hierarchical luminescent cellulose sheet was fabricated viaself-assembly of cadmium selenide (CdSe) nanoparticles capped with trioctylphosphine oxide (TOPO) and 1-hexadecylamine (HDA) onto ultrathin titania film pre-coated cellulose nanofibres of bulk natural cellulose substance (common commercial filter paper). Each cellulose nanofibre of the filter paper was firstly coated with nanometre-thick titania film by means of the surface sol–gel process, followed by alternative deposition of self-assembled layers of stearic acid (SA) and TOPO/HDA capped CdSe nanoparticles, giving a filter paper/titania/SA/(CdSe/SA) composite luminescent sheet possessing stable and well-defined green fluorescence. SEM and TEM observations showed that the resulting luminescent sheet retained the hierarchical structures and morphologies of the initial cellulose substance; meanwhile, the CdSe nanoparticles were anchored on the nanofibre surfaces within SA thin layers through the hydrophobic interaction between the alkyl chains of the surface ligands of CdSe nanoparticles and SA molecules. UV-vis and photoluminescence spectra indicated that the resulting luminescent sheet showed similar characteristic absorption and emission properties as those of the original CdSe nanoparticles. The current approach provides a facile shortcut to fabricate bulk luminescent materials that inherit the mechanical behaviour of cellulose substances and simultaneously possess designed luminescent properties.