Enhanced UV detection by transparent graphene oxide/ZnO composite thin films

Abstract

a All solution processed transparent thin films of graphene oxide (GO) and zinc oxide (ZnO) with different compositions prepared by simple two-step chemical synthesis method have been studied for their UV detection properties. The preparation of GO through oxidation of graphite flakes is followed by sol-gel spin coating deposition of the GO-ZnO composite films on glass substrates. The surface morphology, microstructure and composition of the samples have been studied to confirm the formation of composite thin films comprising of wurtzite-ZnO nanocrystallites and GO flakes. Optical study demonstrates that both the transparency and optical band gap of the samples as estimated from wavelength dependent transmittance curves decrease with the increase of GO content in the films, while the charge carrier concentration increases by 5 fold. The in-plane current-voltage (I-V) measurement with two silver electrodes on the GO-ZnO film shows significant enhancement of photosensitivity in comparison to ZnO films when they are exposed to UV light of different intensities. The response time (t90-response) is nearly three times smaller for GO-ZnO composite films as compared to that of pure ZnO. This improvement is attributed to the defect state modulation and carrier density improvement of the thin films with incorporation of GO which is encouraging to propel optical, electrical and hence optoelectronics applicability of ZnO composite based transparent devices.

Microwave‐Assisted Synthesis of ZnO–rGO Core–Shell Nanorod Hybrids with Photo‐ and Electro‐Catalytic Activity

“…The most dominant and sharpest peak observed in the Raman spectrum of ZnO NRs at 440 cm −1 is due to the intrinsic Raman‐active E 2 mode, which is characteristic of the hexagonal wurtzite phase of ZnO . This result is very similar to that noted previously for ZnO‐graphene/GO hybrid systems . The defect concentration in rGO can be estimated from the D/G band intensity ratio, I D / I G ; the higher this ratio is, the higher the resulting defect concentration.…”

The Influence of Deposition Time on the Structural, Morphological, Optical and Electrical Properties of ZnO-rGO Nanocomposite Thin Films Grown in a Single Step by USP

“…This type of hybrid nanocomposite has attracted much interest mainly due to its highly active surfaces, excellent carrier mobilities and its effective charge-transfer process [6]. Due to these properties, it can be used as a component in ultraviolet photodetectors, transparent electrodes, biomedical sensors, white light-emitting diodes (LEDs), photovoltaic devices, photoluminescent material, gas sensors, photocatalysis, supercapacitors and optical switches [3,[6][7][8][9][10][11][12][13][14].…”

Modified Graphene Oxide Based Zinc Composite: an Efficient Catalyst for N‐formylation and Carbamate Formation Reactions Through CO2 Fixation

“…Synthesis of Graphene oxide was carried out by oxidation of graphite flakes (Aldrich) using the following reported method . In this method, a 200 mL mixture of concentrated H 3 PO 4 and H 2 SO 4 (20 : 180 v/v) was taken in a 500 mL round bottom flask.…”