The Fast and One-Step Growth of ZnO Nanorods on Cellulose Nanofibers for Highly Sensitive Photosensors

Abstract

Cellulose is the most abundant organic material on our planet which has a key role in our daily life (e.g., paper, packaging). In recent years, the need for replacing fossil-based materials has expanded the application of cellulose and cellulose derivatives including into electronics and sensing. The combination of nanostructures with cellulose nanofibers (CNFs) is expected to create new opportunities for the development of innovative electronic devices. In this paper, we report on a single-step process for the low temperature (<100 °C), environmentally friendly, and fully scalable CNF-templated highly dense growth of zinc oxide (ZnO) nanorods (NRs). More specifically, the effect of the degree of substitution of the CNF (enzymatic CNFs and carboxymethylated CNFs with two different substitution levels) on the ZnO growth and the application of the developed ZnO NRs/CNF nanocomposites in the development of UV sensors is reported herein. The results of this investigation show that the growth and nature of ZnO NRs are strongly dependent on the charge of the CNFs; high charge promotes nanorod growth whereas with low charge, ZnO isotropic microstructures are created that are not attached to the CNFs. Devices manufactured via screen printing/drop-casting of the ZnO NRs/CNF nanocomposites demonstrate a good photo-sensing response with a very stable UV-induced photocurrent of 25.84 µA. This also exhibits excellent long-term stability with fast ON/OFF switching performance under the irradiance of a UV lamp (15 W).

Optimization of Electrospray Deposition Conditions of ZnO Thin Films for Ammonia Sensing

“…Due to its unique properties [ 2 ], like transparency in the VIS and NIR spectral ranges, low resistivity, good thermal stability and biocompatibility, ZnO is traditional but increasingly relevant material with applications in different fields such as optoelectronics, pharmacy, and bio- and gas sensing. ZnO nanostructures have been widely used in light emitters, field-effect transistors, lasers, sensors and solar cells [ 3 , 4 , 5 , 6 , 7 ]; for color sensing [ 8 ]; and as transparent conductive oxide [ 9 ]. The morphology-controlled synthesis of ZnO nanostructures has been extensively explored; various nanostructures like nanotubes, nanorods, nanoneedles, nanohelixes and nanodisks have been synthesized by adjusting preparation methods and conditions [ 3 , 10 , 11 , 12 , 13 , 14 , 15 ].…”