Nanorod Thin Films Research Articles

Properties enhancement of TiO2 nanorod thin film using hydrochloric acid etching treatment method

Properties enhancement of TiO2 nanorod thin film using hydrochloric acid etching treatment method

Investigation of omnidirectional transmittance related to ITO nanorods orientation for optical applications

Indium-doped tin oxide (ITO) nanorods thin films were fabricated on silicon (100) wafer and commercial thin film coated glass (ITO-G) substrates via ion-assisted electron-beam evaporation system with inclinable and rotatable substrate setup. The thickness was controlled in the range of 100–400 nm through the QCM monitoring. With the fixed substrate's tilted angle at 85°, the film's structures were respectively observed as the slant and vertical nanorods corresponding to the substrate's rotation speed of 0 and 30 rpm by the field-emission scanning electron microscope (FE-SEM). The grazing-incident X-ray diffraction (GIXRD) and photoelectron spectroscopy (PES) were used to analyze the crystallinity and atomic composition of the ITO nanorods films. It was observed that the films were amorphous and non-significant of composition variation relative to the change of the film's-controlled thickness and structure. The optical transmittance in omnidirectional (omni-T) of p- and s-polarized light was determined through the variable-angle UV-VIS-NIR spectrophotometer. We found the different profiles of the omni-T with the change of film's structure and thickness which could be explained through the generated birefringence of the films. In addition, the different results of the p- and s-polarized were also discussed.

Highly orientated one-dimensional Cu2O/TiO2 heterostructure thin film for photoelectrochemical photoanode and photocatalytic degradation applications

A highly orientated one-dimensional TiO2 nanorod (NR) and TiO2 NR coupled with Cu2O growth on a fluorine doped tin oxide (FTO) substrate were fabricated by the hydrothermal method. A p-n Cu2O/TiO2 heterostructure photoanode was applied for photoelectrochemical water splitting and photocatalytic organic dye degradation application. The purpose of using Cu2O is to extend the visible light absorption capacity and improve the charge transport and charge carrier lifetime of the TiO2 based photoanode. The materials were characterized by various methods. Scanning electron microscopy image revealed that the Cu2O/TiO2 was well aligned perpendicular to the FTO substrate. Energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy confirmed that Cu2O was coated on the TiO2 surface. The absorption spectra showed the energy bandgap of pristine TiO2 decreased after the Cu2O enhancement. Electrochemical impedance spectroscopy revealed that the charge carrier and charge transport of the Cu2O/TiO2 material were improved. Overall photocurrent density generated by the Cu2O/TiO2 photoanodes were higher than the pristine TiO2 photoanode when they were applied as the photoanode in the photoelectrochemical cell. For the thin film Rhodamine B degradation, the Cu2O/TiO2 photocatalyst showed a better performance than the pure TiO2 NR thin film by ∼60%.

Optical and structural properties of WO3 nanostructure films prepared by oblique angle deposition

Tungsten oxide (WO3) nanostructure thin film has been grown on a silicon wafer and glass slide substrate by reactive magnetron sputtering at a different oblique angle from 56°, 70° and 86°. The effect of static and dynamic substrate tilt rotation during the film deposition on microstructure and the optical property was investigated. The results showed that all of the prepared WO3 nanostructure films were amorphous. The film thickness of the prepared films decreased with increasing deposition angles. Field emission scanning electron microscopy (FE-SEM) revealed that the sample prepared at 70° and 86° with substrate tilt rotation was nanocolumnar structure due to the self-shadowing effect. In addition, the optical transmittance with the omnidirectional property was studied by spectrophotometer. The optical transmittance was about to 86% with a good WO3 nanorod thin films as static OAD at 86°. The energy bandgap can be estimated at about 3.11–3.28 eV.

Template-free chemical deposition of highly crystalline ZnO nanorod thin films

Deposition of ZnO nanorod films using a simple solvothermal method with a narrow fluorescence emission due to defects is exemplified. The synthesized ZnO nanorod thin films show excellent potential for UV detection. Their optical properties reflect their semiconducting nature as expected.

Ionization Radiation Shielding Effectiveness of Lead Acetate, Lead Nitrate, and Bismuth Nitrate-Doped Zinc Oxide Nanorods Thin Films: A Comparative Evaluation.

The fabrication of Nano-based shielding materials is an advancing research area in material sciences and nanotechnology. Although bulky lead-based products remain the primary choice for radiation protection, environmental disadvantages and high toxicity limit their potentials, necessitating less costly, compatible, eco-friendly, and light-weight alternatives. The theme of the presented investigation is to compare the ionization radiation shielding potentialities of the lead acetate (LA), lead nitrate (LN), and bismuth nitrate (BN)-doped zinc oxide nanorods-based thin films (ZONRs-TFs) produced via the chemical bath deposition (CBD) technique. The impact of the selected materials’ doping content on morphological and structural properties of ZONRs-TF was investigated. The X-ray diffractometer (XRD) analyses of both undoped and doped TFs revealed the existence of hexagonal quartzite crystal structures. The composition analysis by energy dispersive (EDX) detected the corrected elemental compositions of the deposited films. Field emission scanning electronic microscope (FESEM) images of the TFs showed highly porous and irregular surface morphologies of the randomly aligned NRs with cracks and voids. The undoped and 2 wt.% BN-doped TFs showed the smallest and largest grain size of 10.44 nm and 38.98 nm, respectively. The linear attenuation coefficient (µ) values of all the optimally doped ZONRs-TFs measured against the X-ray photon irradiation disclosed their excrement shielding potency. The measured µ values of the ZONRs-TFs displayed the trend of 1 wt.% LA-doped TF > 1 wt.% LN-doped TF > 3 wt.% BN-doped TF > undoped TFs). The values of μ of the ZONRs-TFs can be customized by adjusting the doping contents, which in turn controls the thickness and morphology of the TFs. In short, the proposed new types of the LA-, LN- and BN-doped ZONRs-TFs may contribute towards the development of the prospective ionization radiation shielding materials.

Hydrothermally fabricated TiO2 heterostructure boosts efficiency of MAPbI3 perovskite solar cells

The electron transport layer (ETL) plays an important role in high-efficiency perovskite solar cells (PSCs). TiO2 nanorod (TNR) thin film with outstanding photovoltaic properties is considered as an excellent ETL in the structure of PSCs. To enhance the efficiency of PSCs, ETL heterostructures with anatase TiO2 nanoparticles (TNPs) and rutile TNRs are fabricated and optimized by two-step hydrothermal process. The maximum efficiency of PSCs based on the ETLs of TiO2 heterostructures in this study is 14.143%, which is much higher than that of PSC cell with the ETL of pure TNRs (9.361%). HypothesisThis study aims to prepare TiO2 heterostructures with two different polymorphic TiO2 (anatase TNPs and rutile TNRs) for high-performance PSCs. ExperimentsTiO2 heterostructures are prepared on conductive FTO substrate by two-step hydrothermal process. Commercial TNPs (P25) are used in different heterostructures for comparison. The structural, morphological characteristics and the current–voltage properties of these ETLs are carefully investigated. FindingsThe enhanced performance of TiO2 heterostructures-based PSCs is believed to be attributed to the excellent capability of carrier extraction, large surface area, light scattering effect and defect passivation at the ETL/perovskite interface.

Highly efficient mode-locked and Q-switched Er3+-doped fiber lasers using a gold nanorod saturable absorber

Mode-locked and Q-switched pulsed fiber laser sources with wavelengths of 1.55 μm are widely used in various fields. Gold nanorods (GNRs) have been applied in biomedicine and optics owing to their biocompatibility, easy fabrication, and unique optical properties. This paper presents the analysis of a saturable absorber based on a colloidal gold nanorod (GNR) thin film for dual-function passively mode-locked and Q-switched 1.55-μm fiber lasers. The colloidal GNR thin film possesses superior properties such as a wide operating wavelength range, large nonlinear absorption coefficient, and a picosecond-order recovery time. Its modulation depth and saturation intensity at 1.55 μm are 7.8% and 6.55 MW/cm2, respectively. Passive mode-locked or Q-switched laser operation is achieved by changing the number of GNR thin-film layers. The advantages of these high-quality GNRs in mode-locked and Q-switched fiber lasers with record-high slope efficiency are verified by conducting comprehensive material and laser dynamic analyses. The self-starting mode-locked fiber laser with an efficiency as high as 24.91% and passively Q-switched fiber laser with the maximum energy of 0.403 μJ are successfully demonstrated. This paper presents the novel demonstration of reconfigurable mode-locked and Q-switched all-fiber lasers by incorporating colloidal GNR thin films.

Growth of zinc oxide nanowires by equimolar solution technique on conducting substrates used for optical applications

Zinc oxide nanorods were successfully fabricated on various substrates coated with metal oxide such as platinum and gold by aqueous solution method. The current research shows the influence of conducting substrates on surface morphology and its use for optical properties zinc oxide nanostructures. Samples were analyzed by energy dispersive (EDX), X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and UV-Visible spectroscopy (UV-vis). The fabricated zinc oxide nanorods exhibit excellent crystalline quality and hexagonal wurzite structure. The Zinc oxide nano-walls and nanorods have crystalline size from 30 to 35 nm. FE-SEM images shows that nanowires and nano-walls grown on metal oxide coated substrates have good hexagonal structure. The zinc oxide nanorods fabricated on Pt coated thin film were highly dense as compared to other substrates coated with metal oxide. The Pt lattice parameter is nearby to Zinc oxide as compared to gold. The value of optical band gap energy (Eg) of zinc oxide nanorods grown on metal oxide was approximated to 3.35 eV that have the nearest value to bulk 3.37 eV. This confirms that Zinc oxide nanorods synthesized by aqueous solution technique have characteristics similar to other conventional techniques either bulk size or thin film nanorods.

Structural characteristics and application of Cu oblique nano-rod thin films for surface-enhanced Raman spectroscopy (SERS)

Structural characteristics and application of Cu oblique nano-rod thin films for surface-enhanced Raman spectroscopy (SERS)

Fabrication of porous 1D WO3 NRs and WO3/BiVO4 hetero junction photoanode for efficient photoelectrochemical water splitting

Porous columnar nanostructured photoelectrodes may significantly affect the photoelectrochemical (PEC) water splitting efficiency. The glancing angle deposition (GLAD) technique is the most popular method to fabricate columnar nanostructured thin films. Here, we have fabricated vertically aligned porous 1D tungsten oxide nano-rod (1D WO3 NRs) thin films by DC magnetron sputtering method using glancing angle deposition with a constant rotation speed of 5 rpm. The depositions carried out at various deposition angles of α = 0°, 60°, 70°, 75°, 80°, and 85°. The deposited 1D WO3 NRs adopted a monoclinic structure oriented in the (002) crystalline plane perpendicular to the FTO substrate. Using systematic deposition conditions, the porous columnar 1D WO3 NRs were engineered to find the effect on the photoelectrochemical water splitting. Photocurrent density of the 1D WO3 NRs photoanodes was tested in near-neutral pH (0.5 M Na2SO4) electrolyte solutions. Under the optimum conditions, the 1D WO3NRs photoanode led to the premier photocurrent density of 1.04 mA/cm2 (1 V vs. Ag/AgCl) due to the optimum surface porosity in the 1D WO3 NRs. The individual layer of BiVO4 photoanode exhibited a photocurrent density of 1.24 mA/cm2 (1V vs. Ag/AgCl). Highest photocurrent density of 2.24 mA/cm2 with high photo-stability was observed in optimized heterostructure of 1D WO3 NRs/BiVO4 photoanode.

Impact of precursor concentrations and substrate type on properties of electrodeposited CdO nanorod thin films for optoelectronic applications

We present here the fabrication of CdO nanorod thin films employing electrochemical deposition technique as low temperature and economical method. Effect of cadmium ions precursor and substrate type were deeply studied to examine structural, morphology, and optical properties of deposited thin films utilizing XRD, SEM, UV–Vis, and PL spectroscopy techniques, respectively. The results designate the formation of a pure phase of face-centered cubic for CdO thin films for different ion concentrations and both substrates. Grown samples have surface morphology of nanorods that changed to nanosheets with increasing Cd+2 ions concentration on ITO substrates while for FTO substrates, it has the same shape with a small decrease in grain sizes. Band gap energy was estimated from the Tauc equation that has average values from 2.5 to 2.2 eV and from 2.5 to 2.3 eV for ITO and FTO, respectively with increasing of molarity from 0.2 to 0.8 M. The growth rate and the conductivity of substrates are the main factors for obtaining different structure, morphology, and different optical band gaps for the fabricated CdO samples as confirmed by current-time curves of electrodeposition process. Photoresponse of the fabricated CdO thin films was evaluated under dark and light conditions. Therefore, our results indicate that the electrodeposited CdO nanorods and nanosheets shapes with different bandgap energy is a promising candidate for the fabrication of optoelectronic devices.

Study the Effect of Annealing Process on Nanorods and Nanonails ZnO Thin Films Prepared by Hydrothermal Technique

Wurtzite hexagonal Zinc oxide (ZnO) nanoorods and nanonails arrays have been successfully fabricated and deposited on glass substrates pre-coated with ZnO seed layer using a simple hydrothermal method. The influence of annealing temperatures of on the morphological, structural and optical properties was studied. The size and shape of the nanostructures and the band gap energy depend on the deposition temperature of ZnO thin films have been studied. The optical energy band gaps of ZnO were calculated to be 3.25 eV and 3.26 eV for the samples annealed at 300°C and 350°C respectively. The XRD results show the formation of wurtzite hexagonal ZnO structures for nanonails and nanorods arrays with prominent (002) orientation. The c/a ratio of 1.6033 is close to the ideal value for hexagonal cell around 1.633. The transmittance of the films is about 80% in the visible range. The (EDX) analysis identified the pure ZnO phase with a ratio of Z:O = 1:1.

Structural characteristics and application of Mn oblique nano-rod thin films as electrodes in gas ionization and field emission sensor

In this work, the performance of a face-to-face gas sensor based on Mn nano-rod thin films with different heights as both electrodes is reported. Paschen’s law and departure from Paschen’s law are studied. The electrodes were fabricated on Ti/Si(400) substrates. The dynamic performance of the sensor was studied at 0.1–1000 mbar gas pressures for gap sizes between 3 and 200 µm for N2, air and CO gases. It was observed that the Paschen’s law is satisfied when the gap size is greater than 10 µm, but at less than this gap size deviation from the Paschen’s law occurs. Results showed that the aspect ratio of the nano-rod directly influences the breakdown voltage. A pronounced resolution for selectivity of the sensor under different conditions of the measurements was obtained, which improved with gas pressure. Comparison of the results with the published works showed higher sensitivity (except those of Chahshouri et al. (Chahshouri et al. in JMM. 30:075001, 2020) for 20 and 100 μm gaps distances) for the three gases studied.

Experimental study of thin film Fe2O3/TiO2 for photocatalytic Rhodamine B degradation

In this work, TiO2 nanorod (NR) and Fe2O3/TiO2 NR thin films for removing organic contaminant in wastewater by employing photocatalytic process were studied. The films were fabricated by hydrothermal method and were characterized by various methods. Structural and surface morphology of samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Chemical bonding and chemical species were analyzed by energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Moreover, the electrochemical impedance spectroscopy (EIS), chopped-light voltammetry (CLV) and photoluminescence (PL) were also investigated. The photocatalytic performance of thin films were tested by Rhodamine B (RhB) degradation under UV light irradiation. Under testing area of 4 cm2, RhB suspended in water was degraded by 30% and 63% by TiO2 and Fe2O3/TiO2 thin film, respectively. The performance increase is due to the Fe2O3/TiO2 heterostructure had faster response to the UV light and had longer charge carrier lifetimes than the pristine TiO2. In addition, the stability of film was also studied. After 3 cycles of uses, the efficiency of RhB degradation was decreased by 28% when compared to the first usage.

Photocatalytic activity and photoelectrochemical properties of Ag/ZnO core/shell nanorods under low-intensity white light irradiation

Zinc oxide (ZnO) nanorod thin films were prepared by CBD onto glass and FTO/glass substrates. Silver (Ag) nanoparticles were synthesized on the surface of the prepared ZnO nanorod thin films using electrochemical methods. The scanning electron microscopy images of the Ag/ZnO/glass core/shell nanostructure confirmed that the average particles size is 20 nm while it was 41 nm for Ag NPs that synthesized onto ZnO/FTO NRs. The photocatalytic activity of the prepared Ag/ZnO core/shell nanostructure was studied by analyzing the degradation of methylene blue (MB) dye under visible light. Various pH values (6 and 10) and exposure time (30–240) min were controlled to investigate the photocatalytic activity of as-prepared Ag/ZnO core/shell nanostructure and that annealed at 200 °C and 300 °C for 1 h. It was observed that when the pH was 6, the degradation rate increased with the annealing temperature and irradiation time reaching 51% at the annealing temperature of 300 °C and exposure time of 240 min. In other hands, when the pH was 10, and the sample was annealed at 200 °C, it showed a good degradation rate of 100% at the irradiation time of 90 min. By contrast, the sample annealed at 300 °C required 180 min to degrade the MB dye completely. The photoelectrochemical cell measurement based on photocurrent density revealed a slight response to light. Cycle voltammetry (CV) measurement was conducted, and the CV curves of the Ag/ZnO core/shell electrodes indicated nonfaradaic and pseudocapacitance behavior. The electrodes showed nearly rectangular CV curves, which indicated the dominance of the nonfaradaic capacitance behavior. The specific capacitance of the electrodes remained at approximately 99%. Mott–Schottky analysis revealed that the semiconductor was an n-type with dependence on flat band potential V FB deviation in the negative direction.

ICMMS-2: Zinc Oxide nano-rods: Challenges for Glucose Biosensors

Zinc oxide nano-rod thin films (ZNR) will be deposited on silicon substrate (ZNRS) and borosilicate glass capillary tube tip (0.5 and 0.7 µm as inner and outer diameters, respectively) (ZNRT) using both Sol-Gel (SG) and aqueous chemical growth (ACG) techniques for glucose biosensor fabrication. It will be functionalized with membranes or enzymes to produce selective glucose biosensor for glucose concentration measurements in extracellular solutions. The prepared thin film samples provided a favourable environment for the glucose oxidase (GOD) immobilization and introduced a shuttling way for electronic communication between electrodes and GOD. The prepared ZNRS and ZNRT structures and morphologies will be characterized by X-ray diffraction (XRD) and Field emission high resolution scanning electron microscopy (FESEM).

C-axis oriented ZnO nanorods based quantum dot solar cells

In this work, for the growth of ZnO (Zinc Oxide) nanorod thin films, the seed layer is prepared by sol-gel dip coating and spin coating methods. We studied the effect of seed layer on structural and optical properties of the ZnO nanorods. FESEM image revealed the difference between the growth of ZnO nanorods on spin and sol-gel dip coated seed layers. It has been observed that ZnO nanorods with uniform size and highly oriented along the c-axis have been grown on spin coated seed layer. HRTEM and Transmission electron microscopy study shows that the ZnO nanorods have an average length of 300 nm and the average diameter is 50 nm, the interplanner spacing is found to be d = 2.63 Å. The X-ray diffraction pattern revealed that the ZnO nanorods are of hexagonal structure. Absorption spectra showed that the ZnO nanorods exhibit UV absorption with absorption peak at 365 nm and the optical band gap has been found to be 3.23 eV. PL spectra indicated the presence of UV and visible emission lying in the range of 380–550 nm. ZnO nanorods based solar cells have been constructed using CdSe quantum dots.

Structural and Optical Properties of ZnO Nanorods Thin Films Prepared by Hydrothermal Method and Effect of growth time

This paper describes, Synthesis of zinc oxide nanorods (ZnO NRs) using hydrothermal technique at different growth time. The structural and morphological properties were characterized by X-ray diffraction (XRD), Energy Dispersive X-Ray (EDX) and Field Emission Scanning Electron Microscope (FE-SEM). The ZnO NRs were obvious hexangular wurtzite structure and preferentially oriented along the c-axis (002) and growth vertically to the substrates. The optical properties were studied. From UV-Visible spectrophotometer and Photoluminescence (PL), the optical band gap energy of all ZnO NRs samples (S1, S2 and S3) were calculated to be (3.425 eV, 3.4 eV, 3.425 eV) respectively. Also, the effect of growth time on ZnO nanorods was studied.

Synthesis of CaFe2O4 Nanorod Thin Film Using Molten Salt Method and Analysis of Its Photoelectrochemical Properties

In this study, calcium ferrite (CaFe2O4) nanorod thin films are synthesized using the molten salt method and applied to photocathodes. SEM observation showed nanorod structure was constructed on Pt...