Effect of synthesis temperature on the UV sensing properties of ZnO-cellulose nanocomposite powder

Zinc oxide-cellulose nanocomposite powder was synthesized by a simple, low cost and two step chemical method. In this work, ZnO nanorods were grown on the cellulose fibers (powder) surfaces at three different temperatures by aqueous chemical method for the fabrication of UV sensor. A very high UV sensitivity was observed for a typical ZnO-cellulose nanocomposite. The morphology, structure and optical properties of the powder were studied by scanning electron microscopy, X-rays diffraction and diffused reflectance spectroscopy, respectively. The percentage compositions of ZnO and cellulose were estimated using thermogravimetric analysis. The Brunauer-Emmett-Teller (BET) surface areas of the ZnO-cellulose nanocomposites were estimated by nitrogen adsorption desorption process. Ultraviolet sensitivity of the ZnO-cellulose nanocomposite were studied by current-voltage measurement followed by time resolved photocurrent study. Due to illumination with ultraviolet light, the photocurrent for a typical ZnO-cellulose nanocomposite pellet increased from 2.728 × 10−8 A to 7.788 × 10−6 A in 15 s. Such a significant enhancement in the conductivity due to UV illumination shows that our ZnO-cellulose can be used for fabrication of UV sensors having ultra-high ON to OFF ratio (IUV/IDark was 285.4).