Papers by Keyword: ZnO Nanorods

Abstract: The present work reports an approach of hydrothermal growth of ZnO nanorods, which simplifies the production of low cost films with controlled morphology for H₂S gas sensor application. The prepared ZnO nanorods exhibit a hexagonal wurtzite phase analyzed by the X-ray diffraction analysis. The FTIR spectra provide information that the band located between 465-570 cm^-1 corresponds to the stretching bond of Zn-O, which confirms the creation of ZnO. PL spectroscopic studies showed that the doping of Ag NPs and f-MWCNT in the ZnO matrix leads to the tuning of the bandgap. The SEM analysis showed the morphology of ZnO was the nanorods. The nanocomposites Ag/ZnO and F-MWCNT/ZnO which prepared, separately were tested for H₂S gas at low (2 ppm) and high (50 ppm) concentrations. ZnO nanorods films showed a sensitivity of 14.71% for pure ZnO with a fast response time of 25.2 sec and recovery time of 33.3 sec towards 2 ppm H₂S. For Ag NPs/ZnO and f-MWCNTs/ZnO, sensors showed a significant sensitivity of 27.95 and 42.39 % at ~150 °C with a response time and recovery time less than pure ZnO. The ZnO sensor showed a higher sensitivity at ~150 °C for both Ag NPs and F-MWCNTs at high gas concentration, where it was 35.085 and 58.89% respectively.

Abstract: Composite rGO/ZnO NRs (NRs = nanorods) have been a photoanode material in DSSC solar cells. In this study, ZnO NRs were synthesized using a hydrothermal method with the addition of hexamethyl tetraamine (HMTA). The synthesized ZnO NRs was then composited with graphene oxide (GO) synthesized by the modified hummers method. The performance of rGO/ZnO NR composite material with various compositions of ZnO: GO ratio (w/w) as a photoanode has been investigated. The results show that graphene oxide is capable of decreasing the ZnO band gap energy. The composite of rGO/ZnO NRs shows its performance as a photoanode material in DSSCs. The composite with ZnO:GO (w/w) ratio of 1:2 showed better performance than the other rGO/ZnO NRs composite.

Abstract: One of Indonesia's most significant issues with technological growth is the lack of electrical energy storage devices. Active materials have low electrical conductivity, accessibility, and ion diffusion. Therefore, it is urgently required to study the combination of higher electrical conductivity ZnO and high surface area of AC-Mn2O3. However, ZnO nanorods (ZnONR) can be modified from ZnO nanoparticles (ZnONP). The structure modification may increase energy density due to having a higher surface area than ZnONP. Three different electrodes with AC-Mn₂O₃ addition various spin coated of 1000 rpm (MZnONR1), 2500 rpm (MZnONR2), and 3000 rpm (MZnONR3). The electrodes were then packaged in a sandwich flat symmetric supercapacitor. The characterization was carried out using X-RD, SEM-EDX cross-section, FTIR, and Cyclic Voltammetric. It is obtained that the highest specific capacitance showed by symmetric supercapacitor MZnONR1 with low speed of spin coating. We also found that the greater the deposited ZnNR content, the lowest thickness until 43.76 μm, the crystallinity until 62% and the highest porosity until 79%. This shows that the MZnONR1 sample exhibits the best electrochemical performance, which is supported by its morphological properties. It is shown that the higher the Zn content, the stability performance AC-Mn₂O₃ supercapacitor higher. ZnONR1 sandwich flat symmetric supercapacitor have a specific capacitance 0.0086 Fg^-1 with an 0.00433 Whg^-1 energy density. Furthermore, it was found that the addition of the AC-Mn₂O₃ increased 2800x compared to the ZnONR1, which reached 28.04 Fg^-1 and an 14.09 Whg^-1 of capacitance specific and energy density, respectively.

Abstract: Photoelectrochemical cell (PEC) has the same working principle as solar cell which convert solar energy into electricity. PEC consists of photoanode, electrolyte, and counter electrode, where electrolyte plays an important role in determining PEC performance. Yttria-stabilized zirconia (YSZ) is the most suitable electrolyte used due to its high ionic conductivity and chemically stable. In this study, YSZ was deposited to ZnO Nanorods (NRs) by doctor blade method with thickness variation of 100 μm (PEC10) and 120 μm (PEC12). X-ray diffraction (XRD), scanning electron microscope (SEM), and UV-Vis spectroscopy were used to distinguish the phase, morphology, and band gap of the formed materials, respectively. Moreover, I-V test was also conducted to evaluate the performance of the fabricated PEC with different YSZ thickness. SEM image confirmed the deposition thickness of YSZ layer on NRs which formed rough and irregular interface due to grain boundary fusion of YSZ and NRs. In addition, there is little difference XRD pattern from PEC10 and PEC12 which shows ZnO and YSZ peaks with peak shifting observed. Meanwhile, slightly difference noticed on band gap value where PEC10 has 3.25 eV and PEC12 has 3.58 eV. Even though, the characteristic of PEC10 and PEC12 is similar, the I-V test shown a significant difference of solar efficiency where PEC10 has higher efficiency of about 0.328% than PEC12. This difference is contributed by smaller grain size which has higher specific surface area and porosity. Based on this study, the thickness of electrolyte layer YSZ doesn’t affect the basic characteristic of PEC but affect the efficiency of PEC significantly.

Abstract: Zinc oxide nanorods zinc oxide nanowire has been deposited on quartz employing a hydrothermal method. The ZnO nanoroad as a seed layer were prepared for the growth process using the drop-casting method. The zincoxide nanomaterials produced were characterized by UV–Visible spectrophotometers, x-ray diffraction, Scanning electron microscopy ,. The crystal structure was calculated from the XRD data and it was confirmed the growth of wurtzite crystalline crystal structures of ZnO NRs. The SEM images revealed high-density nanowires were grown via drop cast coated seed layer. The bandgap in the ZnO NRs film was found to be 3.28 eV. This result was confirmed the formation of ZnO nanostructure. The thermal and electrical properties of ZnO NRs were measured also and analyzed. The conductivity of the ZnO NRs film was modified with the addition of gold nanoparticles using the sputtering technique. These modified films were promising and give an optimized temperature sensor performance.

Abstract: In this study, ZnO nanorods are synthesized by the means of chemical bath deposition (CBD). Further objectives, to study the effect of new parameters (oxygen and air flow) on ZnO nanorods on morphology and length of alignment of the nanorods. It was observed that 0.100M for both zinc nitrate hexahydrate and hexamethylenetetramine give a best result. Here, we added an oxygen gas pressure as others idea in chemical bath deposition method and a p-type silicon substrate to investigate the length of ZnO nanorods through their cross-section. It was found that the biggest grain sizes obtain from sample 14, which is 58.87nm produces a high crystal quality, among others. Sample 14 also has a long nanorods (1.434μm-1.451μm) compared to other samples. The hexagonal structure was observed by Field Emission Scanning Electron Microscope, FESEM and well aligned, compact and perpendicular ZnO nanorods grew on the surface of glass substrate. XRD data shows that it has a larger grain size with low lattice strain. The cross-sectional view of the samples demonstrates long nanorods with a range 2.763μm-2.844μm. Finally, the growth of ultra-long ZnO nanorods by using a modified chemical bath setup was successfully observed and recorded.Keywords: ZnO nanorods, CBD, Growth duration, FESEM images, pressure flow.

Abstract: ZnO Nanorods (NRs) is an excellent material for optoelectronic applications. However, ZnO NRs have a wide bandgap. To overcome this problem, ZnO Nanorods has been doped with nickel (0, 3, and 7 at.%) and then coated by a Cu₂O layer. The ZnO nanorods were first prepared using a hydrothermal method where nickel of varying concentration was added as a dopant. The prepared samples were then coated by Cu₂O using a Chemical Bath Deposition (CBD) method. The fabricated composites were characterized by XRD to identify the phase compositions, SEM-EDX to determine the morphology and elemental compositions, UV-Vis spectroscopy to determine the bandgap, and photocurrent response test to study the sample's response to light. The XRD reveals that the pristine ZnO and Ni-doped ZnO have the same diffraction patterns but the peaks shift to the right with increasing dopant concentrations. The SEM images of all samples show ZnO NRs grew perpendicular to the substrate while its EDX spectra confirm the presence of Nickel in the Ni-doped samples. The UV-Vis spectra showed that the calculated bandgap decreases from ~ 3.2 to 2.7 eV by increasing nickel dopant concentration and adding Cu₂O layer. The photocurrent response measurement shows that the ITO/Zn_0.93Ni_0.07O/Cu₂O sample had a good response to light compared to the two other samples.

Abstract: The electrical and optical properties of nanomaterials depend on their structural form. As an effort to develop an advanced nanomaterial, zinc oxide (ZnO) is interesting to synthesis for many applications such as active material for solar cells and biosensors. This paper provides the role of palladium and plasmonic materials in growing ZnO nanostructure, with a focus on its structural analysis. Nanomaterial ZnO was grown by seed-mediated hydrothermal method with layering by plasmonic materials, i.e. gold (Au) and platinum (Ag). X-ray diffraction analysis shows the presence of three dominant peak angles, i.e 34.43^o, 36.32^o, and 47.49^o corresponding to crystal orientation of (002), (101) and (102), respectively. Palladium (Pd) treatment plus layering by plasmonic materials give a higher size of the nanostructure, but their electric band gaps are decreasing slightly. These findings also supported by high absorbance in UV-vis spectra. Gold layering on the nanomaterial gives a more significant role than platinum which indicated by higher size in diameter and higher absorption of UV-Vis spectra. The average size of pristine ZnO, ZnO:Pd, ZnO:Pd:Ag, and ZnO:Pd:Ag are 44.13, 45.99, 45.28, and 44.81 nm, respectively.

Abstract: In this work, we studied the effect of pre-heating temperature on the structural and optical properties of ZnO nanorods grown by free template sol-gel dip-coating technique. The prepared films were pre-heated at different temperatures: 240, 260, 280 and 300 °C, then annealed at 500 °C for one hour. The structural properties of the prepared samples were investigated by X-ray diffraction (XRD) and the surface morphologies were studied by scanning electron microscope (SEM). The optical properties were studied by means of UV-Visible spectrophotometer. The XRD diffraction spectra show that all the prepared samples have a ZnO wurtzite structure with a preferential orientation along (002) axis. SEM micrographs revealed the formation of well-aligned ZnO nanorods for the sample preheated at 280 °C. The prepared ZnO nanorod structured thin films are highly transparent in the visible region with an average transmittance above 85 % in the 400–800 nm wavelength range.

Abstract: In this work, we report rapid hydrothermal growth of ZnO nanorods on a magnetron sputtered thick ZnO seed layer. The ZnO seed layer on the glass substrarte is monocrystalline and formed by 600 °C annealing for 1 hour after magnetic sputtering. The morphology of the ZnO grain in the ZnO seed layer plays a critical role in the growing of the ZnO nanorods, and the slant ZnO grain results in the slant ZnO nanorod and connected ZnO nonrods. It is found that the average growth of the ZnO nanorods is ~75 nm/minute. The rapid grow rate may be owing to the monocrystallie and the pure water solution of the growth solution.