Highly fluorescent ZnS encapsulated flexible nanocellulose grown by two-step hydrothermal route and their optical, structural and morphological characterisation

Highly fluorescent ZnS-encapsulated flexible nanocellulose synthesised by a two-step hydrothermal route has been reported. The structural studies revealed the hexagonal wurtzite (WZ) ZnS encapsulation in the flexible nanocellulose. Bright ring spot pattern in the selected area electron diffraction observed in the nanocomposite. The crystal size of ZnS5, ZnS10 and ZnS20 agrees with the TEM analysis. The positive slope for samples ZnS5 & ZnS20 and the negative slope for ZnS10 imply the presence of tensile strain and compressive strain, respectively, attributed to lattice distortion. Depending on the density of free sites or defects on the surface of the particles and crystallinity, the luminescence is higher for the ZnS10 and reduced for the other nanocomposites. The maximum UV absorption (290-310 nm) corresponds to the quantum confinement effect of semiconductor NPs and is extremely photoactive in the UV region.

Automated summary

A highly fluorescent ZnS-encapsulated flexible nanocellulose was synthesized using a two-step hydrothermal route. Structural studies confirmed the presence of hexagonal wurtzite (WZ) ZnS in the nanocellulose. The nanocomposite exhibited a bright ring spot pattern in selected area electron diffraction. The luminescence intensity was found to be higher in ZnS10 and lower in the other nanocomposites, attributed to the density of free sites or defects on the surface of the particles and crystallinity. The nanocellulose showed maximum UV absorption in the range of 290-310 nm, indicating strong photoactivity in the UV region due to the quantum confinement effect of semiconductor NPs.