scholarly journals Effects of Growth Temperature on the Physicochemical and Photoelectrochemical Properties of a Modified Chemical Bath Deposited Fe2O3 Photoelectrode

2020 ◽  
Vol 58 (4) ◽  
pp. 263-271
Author(s):  
Yaejin Hong ◽  
Seung-Hwan Jeon ◽  
Hyukhyun Ryu ◽  
Won-Jae Lee
Keyword(s):  
Thin Film ◽  
Film Thickness ◽  
Growth Temperature ◽  
Electrochemical Impedance ◽  
Ph Value ◽  
Saturated Calomel Electrode ◽  
Precursor Solution ◽  
Photocurrent Density ◽  
Flat Band ◽  
Photoelectrochemical Properties

In this study, Fe2O3 photoelectrode thin films were grown on fluorine-doped tin oxide substrates at various temperatures ranging from 145 to 220 oC using modified chemical bath deposition. The morphological, structural, electrical, and photoelectrochemical properties of the resulting Fe2O3 photoelectrode were analyzed using field emission scanning electron microscopy, X-ray diffraction, electrochemical impedance spectroscopy, and a three-electrode potentiostat/galvanostat, respectively. Growth temperature and hydrochloric acid etching both affected the growth of the Fe2O3 photoelectrode, with Fe2O3 thin film thickness first increasing and then decreasing as growth temperature increased. The pH value of the precursor solution varied according to growth temperature, which in turn affected film thickness. The highest photocurrent density (0.53 mA/cm2 at 0.5 V vs. saturated calomel electrode) was obtained from the Fe2O3 photoelectrode grown at 190 oC, which yielded the thickest thin film, smallest full width at half maximum and largest grain size for the (104) and (110) plane, and highest flat-band potential value. Based on these findings, the photoelectrochemical properties of Fe2O3 photoelectrodes grown at various temperatures are strongly affected by their morphological, structural, and electrical properties.

scholarly journals Preparation of nanoporous BiVO 4 /TiO 2 /Ti film through electrodeposition for photoelectrochemical water splitting

2018 ◽  
Vol 5 (9) ◽  
pp. 180728 ◽  
Author(s):  
Dong Hongxing ◽  
Liu Qiuping ◽  
He Yuehui
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Saturated Calomel Electrode ◽  
Photocurrent Density ◽  
Charge Transfer Resistance ◽  
Photoelectrochemical Properties ◽  
Photocatalytic Efficiency ◽  
Transfer Resistance ◽  
Electrodeposition Time ◽  
Absorption Studies

A nanoporous BiVO 4 /TiO 2 /Ti film was successfully fabricated by electrodepositing a nanoporous BiOI film on nanoporous TiO 2 arrays followed by annealing at 450°C for 2 h. The electrodeposition of BiOI film was carried out at different times (10, 30, 100, 500 and 1000 s) in Bi(NO 3 ) 3 and KI solution. The morphological, crystallographic and photoelectrochemical properties of the prepared BiVO 4 /TiO 2 /Ti heterojunction film were examined by using different characterization techniques. UV–vis spectrum absorption studies confirmed an increase in absorption intensities with increasing electrodeposition time, and the band gap of BiVO 4 /TiO 2 /Ti film is lower than that of TiO 2 /Ti. The photocatalytic efficiency of BiVO 4 /TiO 2 /Ti heterojunction film was higher compared to that of the TiO 2 /Ti film owing to the longer transient decay time for BiVO 4 /TiO 2 /Ti film (3.2 s) than that of TiO 2 /Ti film (0.95 s) in our experiment. The BiVO 4 /TiO 2 /Ti heterojunction film prepared by electrodeposition for 1000 s followed by annealing showed a high photocurrent density of 0.3363 mA cm −2 at 0.6 V versus saturated calomel electrode. Furthermore, the lowest charge transfer resistance from electrochemical impedance spectroscopy was recorded for the BiVO 4 /TiO 2 /Ti film (1000 s) under irradiation.

An Electrostatically Self-Assembled Thin Film Made of Zn-Substituted Tungstoborate and Rhodamine B with Photoelectrochemical Properties

2016 ◽  
Vol 16 (4) ◽  
pp. 3674-3678 ◽  
Author(s):  
Xu Mao ◽  
Jia-Ning Zhang ◽  
Li-Hua Gao ◽  
Yu Su ◽  
Peng-Xia Chen ◽  
...  
Keyword(s):  
Thin Film ◽  
Rhodamine B ◽  
Indium Tin Oxide ◽  
Saturated Calomel Electrode ◽  
Photocurrent Density ◽  
Layer By Layer ◽  
Applied Potential ◽  
Ito Glass ◽  
Keggin Polyoxometalate ◽  
Self Assembled

An electrostatically self-assembled multilayer thin film consisting of alternating layers of Keggin polyoxometalate of Zn-substituted tungstoborate (BW11Zn) and Rhodamine B (RhB) has successfully been prepared on a quartz and indium-tin oxide (ITO) glass substrate. The ultraviolet-visible (UV-vis) absorption spectra demonstrated that the electrostatically self-assembled film of (BW11Zn/RhB)n was uniformly deposited layer by layer, and the RhB molecules in the film formed the J-aggregation. The photoelectrochemical investigations showed that the films generated stable cathodic photocurrents that originated from RhB, and the maximal cathodic photocurrent density generated by an eight-layer film was 4.9 μA/cm2 while the film was irradiated with 100 mW/cm2 polychromatic light of 730 nm > λ > 325 nm at an applied potential of 0 V versus a saturated calomel electrode.

scholarly journals Effect of Aging Time and Film Thickness on the Photoelectrochemical Properties of TiO2Sol-Gel Photoanodes

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
D. Regonini ◽  
A. K. Alves ◽  
F. A. Berutti ◽  
F. Clemens
Keyword(s):  
Film Thickness ◽  
Aging Time ◽  
Sol Gel ◽  
Photocurrent Density ◽  
Photoelectrochemical Properties ◽  
Solar Water Splitting ◽  
Electron Collection ◽  
Significant Difference ◽  
Sol Gel Process ◽  
Sol Gel Films

This work has focused on the investigation of a non-aqueous based sol-gel process to produce TiO2based photoelectrodes for solar water splitting. In particular, the effect of the aging time of the sol and TiO2film thickness on the photoelectrochemical properties of the photoanodes has been investigated. In order to achieve optimal performances (i.e., photocurrent density up to 570 µA/cm2and IPCE of 26% at 300 nm), the sol needs to be aged for 3 to 6 h, before being dip-coated to produce the photoanodes. The importance of the aging time can also be appreciated from the optical properties of the TiO2films; the absorbance threshold of the sol-gel aged for 3–6 h is slightly shifted towards longer wavelenghts in comparison to 0 h aging. Aging is necessary to build up a well-interconnected sol-gel network which finally leads to a photoelectrode with optimized light absorption and electron collection properties. This is also confirmed by the higher IPCE signal of aged photoelectrodes, especially below 340 nm. Among thicknesses considered, there is no apparent significant difference in the photoresponse (photocurrent density and IPCE) of the TiO2sol-gel films.

scholarly journals Nanostructured Magnéli-Phase W18O49 Thin Films for Photoelectrochemical Water Splitting

Catalysts ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 526
Author(s):  
A. K. Mohamedkhair ◽  
Q. A. Drmosh ◽  
Mohammad Qamar ◽  
Z. H. Yamani
Keyword(s):  
Thin Film ◽  
Water Oxidation ◽  
Oxidation Reaction ◽  
Electrochemical Impedance ◽  
Saturated Calomel Electrode ◽  
Oxide Thin Film ◽  
Solution Ph ◽  
Visible Radiation ◽  
Magnéli Phase ◽  
Magneli Phase

Converting water into hydrogen through the photo-electrochemical (PEC) process is one of the most exciting approaches in this field, and there is a quest to design or search for new electro-photo-catalytic materials. In this work, simple steps for fabrication and transformation of metallic tungsten thin film into the photo-active Magnéli-phase (W18O49) of tungsten oxide thin film is demonstrated. The post-annealing temperature has a significant impact on the phase evolution of tungsten film into W18O49. The film thickness of W18O49 is controlled by controlling the sputtering time (or deposition time) of W film. The PEC performance of the as-prepared electrodes is evaluated by monitoring the water oxidation reaction under visible radiation. The PEC findings reveal a correlation between PEC performance and phase, morphology, and thickness of the film. The as-derived W18O49 can efficiently catalyze the water oxidation reaction at neutral solution pH, generating 0.6 and 1.4 mA cm−1 photo-current at 0.6 and 0.8 V vs. Saturated calomel electrode (SCE), respectively, in addition to excellent stability. The electrical conductivity and the charge transfer kinetics are investigated employing the electrochemical impedance spectroscopic (EIS) technique.

scholarly journals High-Throughput Characterization of Structural and Photoelectrochemical Properties of a Bi–Mo–W–O Thin-Film Materials Library

2020 ◽  
Vol 234 (5) ◽  
pp. 835-845 ◽  
Author(s):  
Mona Nowak ◽  
Ramona Gutkowski ◽  
Joao Junqueira ◽  
Wolfgang Schuhmann ◽  
Alfred Ludwig
Keyword(s):  
Thin Film ◽  
High Throughput ◽  
Lattice Distortion ◽  
Photocurrent Density ◽  
Diffraction Peak ◽  
Photoelectrochemical Properties ◽  
Aurivillius Phase ◽  
Photoelectrochemical Performance ◽  
Photoelectrochemical Activity

AbstractA Bi–W–Mo–O thin-film materials library was fabricated by combinatorial reactive magnetron sputtering. The composition spread was investigated using high-throughput methods to determine crystalline phases, composition, morphology, optical properties, and photoelectrochemical performance. The aurivillius phase (Bi2O2)2+ (BiM(W1−NMoN)M−1O3M+1)2− is the predominantly observed crystal structure, indicating that the thin films in the library are solid solutions. With increasing amounts of Mo ≙ 7–22% the diffraction peak at 2θ = 28° ≙ [131] shifts due to lattice distortion, the photoelectrochemical activity is increasing up to a wavelength of 460 nm with an incident photon to current efficiency (IPCE) of 4.5%, and the bandgap decreases. A maximum photocurrent density of 31 μA/cm2 was measured for Bi31W62Mo7Oz at a bias potential of 1.23 V vs. RHE (0.1 M Na2SO4).

scholarly journals Foam-like 3D Graphene as a Charge Transport Modifier in Zinc Oxide Electron Transport Material in Perovskite Solar Cells

Photochem ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 523-536
Author(s):  
Mohamed Salleh Mohamed Saheed ◽  
Norani Muti Mohamed ◽  
Balbir Singh Mahinder Singh ◽  
Qamar Wali ◽  
Mohamed Shuaib Mohamed Saheed ◽  
...  
Keyword(s):  
Solar Cells ◽  
Electron Transport ◽  
Charge Transport ◽  
Electrochemical Impedance ◽  
Perovskite Solar Cells ◽  
Precursor Solution ◽  
Photocurrent Density ◽  
Transport Parameters ◽  
3D Graphene ◽  
A Charge

The effect of foam-like 3D graphene (3DG) in an electron transport material (ETM), viz. ZnO thin film, on the steady-state photoluminescence (PL), light-harvesting efficiency (LHE), photocurrent density (JSC), photovoltage (VOC), and charge transport parameters of perovskite solar cells (PSCs) are systematically investigated. The ETM is developed by spin coating a ZnO precursor solution containing varying amounts of 3DG on conducting glass substrates and appropriate annealing. A significant improvement in the photoconversion efficiency of PSCs is observed for a low concentration of 3DG in ZnO. The current–voltage and electrochemical impedance spectroscopy measurements show that the addition of 3DG enhances the VOC due to efficient electron–hole separation and charge transport compared to the pristine ZnO. These studies offer a route for further advances in enhancing the optoelectronic properties of ETM for artificial photosynthesis and photocatalysis devices.

scholarly journals Improvement of Photoelectrochemical Properties of WO3 Photoelectrode Fabricated by Using H2O2 Additive

2021 ◽  
Vol 59 (3) ◽  
pp. 177-186
Author(s):  
Seung-Hwan Jeon ◽  
Hyunjin Jeong ◽  
Seongchan Bae ◽  
Hyukhyun Ryu ◽  
Won-Jae Lee
Keyword(s):  
Current Density ◽  
Dark Current ◽  
Photocurrent Density ◽  
Flat Band ◽  
Photoelectrochemical Properties ◽  
Dark Current Density ◽  
Potential Donor ◽  
Large Influence ◽  
Vis Spectroscopy ◽  
Coating Method

In this study, we deposited a WO3 thin-film photoelectrode on a fluorine-doped tin oxide (FTO) substrate using a spin-coating method, and we investigated the photocurrent density and dark current density of the WO3 photoelectrode with various amounts of H2O2 additive. The morphological, structural, optical, electrical and photoelectrochemical properties of the WO3 photoelectrode with various amounts of H2O2 additive were analyzed using FE-SEM, XRD, UV-vis spectroscopy, EIS and a three-electrode potentiostat/galvanostat system, respectively. The amount of H2O2 additive has a large influence on the thickness of the WO3 photoelectrode, XRD (100) peak intensity, light absorption, optical energy bandgap, flat-band potential, donor density value, etc., and thus has a large influence on photoelectrochemical properties. Specifically, the H2O2 additive had a large influence on the growth of the WO3 photoelectrode, and the photocurrent density and dark current density characteristics of the WO3 photoelectrode grown to a uniform and thick thickness were largely improved. As a result, the WO3 photoelectrode fabricated with 0.2 mL of added H2O2 exhibited a high photocurrent density value of 1.17 mA/cm<sup>2</sup>, which was about 23 times higher than that of the WO3 photoelectrode fabricated without H2O2 additive, and had a dark current density value of a low 0.04 mA/cm<sup>2</sup>, which was a reduction of about 87%.

scholarly journals Silicon Carbide-Gated Nanofluidic Membrane for Active Control of Electrokinetic Ionic Transport

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 535
Author(s):  
Antonia Silvestri ◽  
Nicola Di Trani ◽  
Giancarlo Canavese ◽  
Paolo Motto Ros ◽  
Leonardo Iannucci ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Silicon Carbide ◽  
Power Consumption ◽  
Low Power ◽  
Electrochemical Impedance ◽  
Field Effect Transistors ◽  
External Control ◽  
Low Power Consumption ◽  
Flat Band ◽  
Ionic Field

Manipulation of ions and molecules by external control at the nanoscale is highly relevant to biomedical applications. We report a biocompatible electrode-embedded nanofluidic channel membrane designed for electrofluidic applications such as ionic field-effect transistors for implantable drug-delivery systems. Our nanofluidic membrane includes a polysilicon electrode electrically isolated by amorphous silicon carbide (a-SiC). The nanochannel gating performance was experimentally investigated based on the current-voltage (I-V) characteristics, leakage current, and power consumption in potassium chloride (KCl) electrolyte. We observed significant modulation of ionic diffusive transport of both positively and negatively charged ions under physical confinement of nanochannels, with low power consumption. To study the physical mechanism associated with the gating performance, we performed electrochemical impedance spectroscopy. The results showed that the flat band voltage and density of states were significantly low. In light of its remarkable performance in terms of ionic modulation and low power consumption, this new biocompatible nanofluidic membrane could lead to a new class of silicon implantable nanofluidic systems for tunable drug delivery and personalized medicine.

scholarly journals High performance, electroforming-free, thin film memristors using ionic Na0.5Bi0.5TiO3

2021 ◽  
Vol 9 (13) ◽  
pp. 4522-4531
Author(s):  
Chao Yun ◽  
Matthew Webb ◽  
Weiwei Li ◽  
Rui Wu ◽  
Ming Xiao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Resistive Switching ◽  
Growth Temperature ◽  
High Performance ◽  
20 Nm

Interfacial resistive switching and composition-tunable RLRS are realized in ionically conducting Na0.5Bi0.5TiO3 thin films, allowing optimised ON/OFF ratio (>104) to be achieved with low growth temperature (600 °C) and low thickness (<20 nm).

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