scholarly journals Hybrid ZnO Flowers-Rods Nanostructure for Improved Photodetection Compared to Standalone Flowers and Rods

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1464
Author(s):  
Abdullah M. Al-Enizi ◽  
Shoyebmohamad F. Shaikh ◽  
Asiya M. Tamboli ◽  
Afifa Marium ◽  
Muhammad Fazal Ijaz ◽  
...  
Keyword(s):  
Uv Light ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Zno Nanorods ◽  
Current Response ◽  
The Novel ◽  
X Ray Diffraction ◽  
Sensor Performance ◽  
Current Voltage ◽  
Response Current

Different Zinc Oxide (ZnO) morphologies have been used to improve photodetector efficiencies for optoelectronic applications. Herein, we present the very novel hybrid ZnO flower-rod (HZFR) morphology, to improve photodetector response and efficiency when compared to the prevalently used ZnO nanorods (NRs) and ZnO nanoflowers (NFs). The HZFR was fabricated via sol-gel microwave-assisted hydrothermal methods. HZFR achieves the benefits of both NFs, by trapping a greater amount of UV light for the generation of e-h pairs, and NRs, by effectively transporting the generated e-h pairs to the channel. The fabricated photosensors were characterized with scanning electron microscopy, X-ray diffraction, photoluminescence, and a Keithley 4200A-SCS parameter analyzer for their morphology, structural characteristics, optical performance, and electrical characteristics, respectively. The transient current response, current-voltage characteristics, and responsivity measurements were set as a benchmark of success to compare the sensor response of the three different morphologies. It was found that the novel HZFR showed the best UV sensor performance with the fastest response time (~7 s), the highest on-off ratio (52), and the best responsivity (126 A/W) when compared to the NRs and NFs. Hence, it was inferred that the HZFR morphology would be a great addition to the ZnO family for photodetector applications.

scholarly journals Area-Selective ZnO Thin Film Deposition on Variable Microgap Electrodes and Their Impact on UV Sensing

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Q. Humayun ◽  
M. Kashif ◽  
U. Hashim
Keyword(s):  
Thin Films ◽  
Uv Light ◽  
Sol Gel ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Dynamic Responses ◽  
X Ray Diffraction ◽  
Current Voltage ◽  
Conventional Photolithography ◽  
Photolithography Process

ZnO thin films were deposited on patterned gold electrodes using the sol-gel spin coating technique. Conventional photolithography process was used to obtain the variable microgaps of 30 and 43 μm in butterfly topology by using zero-gap chrome mask. The structural, morphological, and electrical properties of the deposited thin films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and Keithley SourceMeter, respectively. The current-voltage (I-V) characterization was performed to investigate the effect of UV light on the fabricated devices. The ZnO fabricated sensors showed a photo to dark current (Iph/Id) ratios of 6.26 for 30 μm and 5.28 for 43 μm gap electrodes spacing, respectively. Dynamic responses of both fabricated sensors were observed till 1V with good reproducibility. At the applied voltage of 1 V, the response time was observed to be 4.817 s and 3.704 s while the recovery time was observed to be 0.3738 s and 0.2891 s for 30 and 43 μm gaps, respectively. The signal detection at low operating voltages suggested that the fabricated sensors could be used for miniaturized devices with low power consumption.

Nanostructured TiO2-Based Composites for Light Absorption

2014 ◽  
Vol 975 ◽  
pp. 207-212
Author(s):  
Dayse I. dos Santos ◽  
Olayr Modesto Jr. ◽  
Luis Vicente A. Scalvi ◽  
Americo S. Tabata
Keyword(s):  
Metal Oxide ◽  
Light Absorption ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Second Phase ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Oxide Powders

Metal oxide nanocomposites were prepared by two different routes: polyol and sol-gel. Characterization by X ray diffraction showed that the first process produces directly a two-phase material, while the sol-gel powder never showed second phase below 600°C. Light spectroscopy of the treated powders indicated similarities for the processed materials. Although the overall material compositions are about the same, different structural characteristics are found for each processing. With the exception of Ti-Zn materials, all the double metal oxide powders showed higher absorbance than either TiO2 powder.

Photocatalytically Active Cotton Fabrics Produced with Anatase Synthesized Using a Low-Temperature Sol-Gel Process

2018 ◽  
Vol 762 ◽  
pp. 408-412
Author(s):  
Raivis Eglītis ◽  
Gundars Mežinskis
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
Anatase Nanoparticles ◽  
Pre Treatment

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.

Resistive Switching Behaviour of Dip Coated ZnO Films with the Changing with Drawal Speed

2020 ◽  
Vol 978 ◽  
pp. 384-389
Author(s):  
Sritama Roy ◽  
Saswati Soumya Dash ◽  
Prasanna Kumar Sahu ◽  
Smita Mishra ◽  
Jyoti Prakash Kar
Keyword(s):  
Thin Films ◽  
Resistive Switching ◽  
Sol Gel ◽  
Dip Coating ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Thin Film Thickness ◽  
Withdrawal Speed ◽  
Current Voltage ◽  
P Type

Zinc Oxide (ZnO) thin films were produced by the sol gel dip coating process on the p-type silicon substrate with various withdrawal speeds changing from 1 to 4 cm/min, respectively. The films were annealed at a temperature of 500 °C for an hour in air ambient. The thin film thickness was found to be raised with the rise in withdrawal speed. The uniform distribution of the grains was appeared for all the films. The evolution of c-axis oriented (002) peak was revealed from X-ray diffraction (XRD) studies. The microstructural and optical properties of ZnO films were investigated by Raman, FTIR and photoluminescence spectroscopy (PL). The resistive switching properties of ZnO based memristors were studied by performing the current-voltage (I-V) measurements, where the thin films coated with lower withdrawal speed, have shown better switching property with rapid rise and fall of current during SET and RESET process, respectively.

The Effect of Stabiliser’s Molarity to the Growth of ZnO Nanorods

2011 ◽  
Vol 312-315 ◽  
pp. 99-103 ◽  
Author(s):  
Zuraida Khusaimi ◽  
Mohamad Hafiz Mamat ◽  
Mohd Zainizan Sahdan ◽  
Norbani Abdullah ◽  
Mohamad Rusop
Keyword(s):  
Sol Gel ◽  
Zno Nanorods ◽  
Structural Features ◽  
Zinc Nitrate ◽  
Molar Ratio ◽  
Nitrate Hexahydrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wet Chemical ◽  
Gel Preparation

A wet chemical approach, originating from sol-gel preparation, was adopted with the intention to develop a low-temperature benign method of preparation. ZnO nanorods are successfully grown in an aqueous medium. The precursor, zinc nitrate hexahydrate (Zn(NO3)2.6H2O), is stabilized by hexamethylene tetraamine (HMTA). The effect of changing the molarity of HMTA to the structural orientation of ZnO nanorods is investigated. X-ray diffraction of the synthesized ZnO shows hexagonal zincite structure. The structural features of the nanocrystalline ZnO were studied by SEM. Structural features, surface morphology and differences in lattice orientation are seemingly influenced by varying the Zn2+: HMTA molar ratio. The formation of ZnO nanorods with blunt and sharp tips is found to be significantly affected by this ratio.

RAMAN STUDY OF VANADIUM-DOPED TITANIA NANOPOWDERS SYNTHESIZED BY SOL-GEL METHOD

2010 ◽  
Vol 24 (06n07) ◽  
pp. 667-675 ◽  
Author(s):  
M. ŠĆEPANOVIĆ ◽  
S. AŠKRABIĆ ◽  
M. GRUJIĆ-BROJČIN ◽  
A. GOLUBOVIĆ ◽  
Z. DOHČEVIĆ-MITROVIĆ ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Structural Characteristics ◽  
Anatase Phase ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Synthesis Conditions ◽  
Raman Modes ◽  
Doped Titania

Pure titania ( TiO 2) nanopowders and TiO 2 doped with 10 mol % of vanadium ions ( V 3+) are synthesized by sol-gel method. The dependence of structural characteristics of nanopowders on synthesis conditions is investigated by X-ray diffraction and Raman spectroscopy. Very intensive modes observed in Raman spectra of all nanopowders are assigned to anatase phase of TiO 2. Additional Raman modes of extremely low intensity which can be related to the presence of small amount of brookite amorphous phase are observed in pure TiO 2 nanopowders. In V -doped nanopowders anatase was the only TiO 2 phase detected. The variations in duration and heating rate of calcination influence slightly the Raman spectra of pure TiO 2, but have a great impact on Raman modes of anatase, as well as the additional Raman modes related to the presence of vanadium oxides in V -doped samples.

scholarly journals Synthesis of Ca-Doped Three-Dimensionally Ordered Macroporous Catalysts for Transesterification

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Tanat Chokpanyarat ◽  
Vittaya Punsuvon ◽  
Supakit Achiwawanich
Keyword(s):  
Reaction Time ◽  
Catalyst Concentration ◽  
Sol Gel ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hierarchical Porous ◽  
Ordered Macroporous

The novel three-dimensionally ordered macroporous (3DOM) CaO/SiO2, 3DOM CaO/Al2O3, and 3DOM Ca12Al14O32Cl2 catalysts for biodiesel transesterification were prepared by sol-gel method. The 3DOM catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The hierarchical porous structure was achieved; however, only 3DOM CaO/Al2O3 and 3DOM Ca12Al14O32Cl2 catalysts were used for transesterification due to high amount of active CaO. Various parameters such as methanol to oil molar ratio, catalyst concentration, reaction time, and their influence on the biodiesel production were studied. The result showed that 99.0% RPO conversion was achieved using the 3DOM Ca12Al14O33Cl2 as a catalyst under the optimal condition of 12 : 1 methanol to oil molar ratio and 6 wt.% catalyst with reaction time of 3 hours at 65°C.

N-Doped Cu11O2 (VO4)6 Photocatalyst Prepared by Sol-Gel Method

2011 ◽  
Vol 393-395 ◽  
pp. 1287-1290
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Qi Xing
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Photodegradation Rate ◽  
Triclinic Phase ◽  
Synthesized Materials

The N-doped Cu11O2 (VO4)6 photocatalyst was prepared using the sol-gel method. Techniques of X-ray diffraction (XRD), scanning electron microscope (SEM) have been employed to characterize the as-synthesized materials. During liquid phase photocatalytic degradation of Methy lorange(MO) under the UV-light, the as-prepared N-doped Cu11O2 (VO4)6 exhibits higher activity than the pure Cu11O2 (VO4)6 without doped N. It found that the N-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, N/Cu molar ratio of 12%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 94.42% or so in 60min under 20W ultraviolet lamp.

Synthesis of a New Red Long Persistent Phosphor Sr2ZnSi2O7: Eu3+, Lu3+ via Sol–Gel Method and Investigation of its Luminescence

2011 ◽  
Vol 393-395 ◽  
pp. 362-365
Author(s):  
Hua Lin ◽  
A Xiao Xu ◽  
Guo Liang Chen ◽  
Zi Shan Zheng ◽  
Heng Lin ◽  
...  
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Trap Depth ◽  
X Ray Diffraction ◽  
Red Phosphor ◽  
Gel Method ◽  
Sol Gel Method ◽  
Long Afterglow ◽  
Uv Light Irradiation ◽  
Luminescent Centers

A novel red long persistent phosphor of Sr2ZnSi2O7: Eu3+, Lu3+ was successfully synthesized with sol–gel method. Its properties were systematically characterized by X-ray diffraction(XRD), luminescence, afterglow decay curves and thermoluminescence (TL) spectra. The red phosphor showed one emission peak at 616.9nm, which is attributed to the typical 5D0–7F2 transition of Eu3+ ions as luminescent centers in Sr2ZnSi2O7 host. Lu3+ as a sensitized ion played an important role in enhancing the long afterglow performance of Sr2ZnSi2O7: Eu3+, Lu3+. Under UV light irradiation, this phosphor showed obvious red long-lasting phosphorescence that can be clearly seen with naked eyes in a dark room for over 20s after the irradiation source has been removed. Thermoluminescence (TL) measurement showed that Lu3+ co-dopan can reduce the trap depth of the title phosphor to obtain suitable ones.

Self-Cleaning TiO2/SiO2 Thin Film Prepared by a Simple Sol-Gel Method

2014 ◽  
Vol 804 ◽  
pp. 157-160
Author(s):  
Wen Xiu Liu ◽  
Jun Na Xu ◽  
Jun Zhang ◽  
Xue Mei Liu ◽  
Wen Bin Cao
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Sulfate Solution ◽  
Ultraviolet Region ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Titanyl Sulfate ◽  
Glass Substrates ◽  
Light Region ◽  
Vis Spectroscopy

TiO2 thin films were prepared on SiO2-coated glass substrates using sols deriving from high concentration titanyl sulfate solution by the spin-coating technique. The calcined films were characterized by X-ray diffraction, UV-Vis spectroscopy, scanning electron microscopy. The film exhibited high transmittance in the visible light region and high absorption in the ultraviolet region. The contact angle of SiO2/TiO2 decreased to below 5° under 30 min of UV light irradiation and can sustain for 1 weeks.

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