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Fabrication of self-organised highly ordered titanium oxide nanotube arrays by anodic oxidation and characterisation
, Article International Journal of Nanomanufacturing ; Volume 5, Issue 3-4 , 2010 , Pages 297-309 ; 17469392 (ISSN) ; Ahadian, M. M ; Iraji Zad, A ; Taghavinia, N ; Dolati, A. G ; Sharif University of Technology
2010
Abstract
Self-organised and vertically oriented titanium oxide nanotube array (TNTA) has been synthesised by potentiostat anodisation of Ti foil in fluoride-based electrolyte. By varying the anodisation voltage from 8 V to 24 V it was possible to gradually change the topologies of nanotubes. The size of TNTAs was measured using SEM images and also determined based on a non-destructive optical method. In addition, photoelectrochemical properties of nanotubular TiO2/Ti electrodes were examined by anodic photocurrent response, potentiodynamic polarisation measurements and electrochemical impedance spectroscopy. A general equivalent circuit model was proposed for photoelectrochemical system consists of...
Fabrication of dual-phase TiO2/WO3with post-illumination photocatalytic memory
, Article New Journal of Chemistry ; Volume 44, Issue 46 , 2020 , Pages 20375-20386 ; Nguyen, D. T ; Diamanti, M. V ; Kaveh, R ; Asa, M ; Sakar, M ; Pedeferri, M ; Do, T. O ; Sharif University of Technology
Royal Society of Chemistry
2020
Abstract
This study describes the synthesis of TiO2/WO3 composite systems with a varying concentration of WO3 by a glucose-template assisted method and demonstrates their round-the-clock photoactivity performance towards the degradation of methanol (MeOH) under illumination and dark conditions. XRD results indicated a biphasic anatase-rutile nature of TiO2, with tunable concentrations with respect to the WO3 loading. WO3 incorporation extended the light absorption of the system towards visible light, increasing the observed photoactivity. The obtained results were further validated using photo-electrochemical investigations such as photocurrent measurements and the impedance response of the systems....
How CdS nanoparticles can influence TiO2 nanotube arrays in solar energy applications?
, Article Applied Catalysis B: Environmental ; Volume 162 , January , 2015 , Pages 210-216 ; 09263373 (ISSN) ; Naseri, N ; Moradlou, O ; Azimirad, R ; Moshfegh, A. Z ; Sharif University of Technology
Elsevier
2015
Abstract
In this study, titanium dioxide (TiO2) nanotube array (TNA) films are fabricated via anodization of titanium (Ti) sheet. After annealing, the films consisted of well ordered, vertically oriented TNAs of 125±6nm diameter, 38±3nm wall thickness, and 2.9±0.3μm in length. Cadmium sulfide (CdS) nanoparticles are deposited on the synthesized TNAs by sequential-chemical bath deposition (S-CBD) method with different immersion cycle (n) to produce heterogeneous TNA/CdS-n (n=10, 20 and 30) nanostructures. UV-visible absorption spectra of the samples revealed that the absorption edge of CdS modified TNAs was shifted to a higher wavelength with respect to the pure TNAs indicating band gap reduction of...
Newly designed ternary hematite-based heterojunction for PEC water splitting
, Article Applied Surface Science ; Volume 550 , 2021 ; 01694332 (ISSN) ; Eftekharinia, B ; Tayebi, M ; Lee, B. K ; Naseri, N ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Hematite is recognized as a promising photoanode for photoelectrochemical water oxidation to produce solar hydrogen due to its favorable properties. However, the high charge carrier recombination rate due to low electrical conductivity and sluggish oxygen reduction kinetics of pure hematite hinder its photocatalytic activity. This work proposed a new hematite-based heterostructure of Ti-Fe2O3/Fe2TiO5/FeOOH, synthesized through a hydrothermal method. The photoanode morphology was branched nanorods that expanded their surface area and improved charge transfer at the photoanode/electrolyte interface. In a novel and complement modification approach, a thin pseudobrookite interlayer was applied...
Plasmonic enhancement of photocurrent generation in two-dimensional heterostructure of WSe2/MoS2
, Article Nanotechnology ; Volume 32, Issue 32 , 2021 ; 09574484 (ISSN) ; Esfandiar, A ; Sharif University of Technology
IOP Publishing Ltd
2021
Abstract
Enhancing the photoresponse of single-layered semiconductor materials is a challenge for high-performance photodetectors due to atomically thickness and limited quantum efficiency of these devices. Band engineering in heterostructure of transition metal chalcogenides (TMDs) can sort out part of this challenge. Here, we address this issue by utilizing the plasmonics phenomenon to enrich the optoelectronics property of the WSe2/MoS2 heterojunction and further enhancement of photoresponse. The introduced approach presents a contamination-free, tunable and efficient way to improve light interactions with heterojunction devices. The results showed a 3600-fold enhancement in photoresponsivity and...
A computational investigation on the influence of different π spacer groups in the bithiazole-based organic dye sensitizers on the short-circuit photocurrent densities of dye-sensitized solar cells
, Article Journal of Photochemistry and Photobiology A: Chemistry ; Volume 333 , 2017 , Pages 70-78 ; 10106030 (ISSN) ; Hadipour, N. L ; Parsafar, G ; Sharif University of Technology
Elsevier B.V
2017
Abstract
A series of experimentally synthesized metal free organic dyes based on the 2-Cyano-3-(5-(5'-(4-(diphenylamino)phenyl)-4,4'-dihexyl-2,2'-bithiazol-5-yl)thiophen-2-yl)acrylic acid (dye 1) were investigated, based on computational methods to shed light on how a tiny difference in π-linker of sensitizer, C[tbnd]C and thiophene moiety as the additional π spacer group in dyes 2 and 3 respectively, has a significant impact on the short-circuit photocurrent densities (JSC) in Dye-sensitized solar cells (DSSCs). Although dyes 2 and 3 have similar redshifts in comparison to dye 1 in the UV–vis absorption spectra, there is a significant difference between JSC values of these dyes resulting in...
CdS nanoparticle sensitized titanium dioxide decorated graphene for enhancing visible light induced photoanode
, Article Applied Surface Science ; Vol. 320, issue , 30 November , 2014 , pp. 772-779 ; ISSN: 01694332 ; Faraji, M ; Nien, Y. T ; Moshfegh, A. Z ; Sharif University of Technology
Abstract
CdS/TiO2/graphene (CTG) nanocomposite thin films were synthesized by a facile production route. The TiO2/graphene (TG) nanocomposite was initially fabricated by sol-gel method in such a way that TiO2 nanoparticles loaded on graphene oxide (GO) sheet via photocatalytic process. Then, CdS nanoparticles were deposited on the TG thin film by successive ion layer adsorption and reaction process (SILAR) approach. Based on atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses, the TG thin film possessed a larger surface area as compared with the pure TiO2 thin film due to presence of graphene sheet. UV/visible spectroscopy exhibited...
UV photodetection of laterally connected ZnO rods grown on porous silicon substrate
, Article Sensors and Actuators, A: Physical ; Volume 180 , 2012 , Pages 11-14 ; 09244247 (ISSN) ; Dariani, R. S ; Iraji Zad, A ; Sharif University of Technology
2012
Abstract
Here, the UV photodetection of ZnO rods grown on porous silicon substrates are reported. Laterally interconnected ZnO rods have been synthesized by chemical vapor transport and condensation method on porous silicon substrates. As characterized by current-voltage measurements the I-V characteristics have linear behavior, indicating space charge effect. The device exhibits photocurrent response of 0.027 A/W for 325 nm UV light under -5 V bias. The rise and decay time constants under these conditions are 19 and 62 s, respectively
Effect of ZnO nanoparticles coating layers on top of ZnO nanowires for morphological, optical, and photovoltaic properties of dye-sensitized solar cells
, Article Micromachines ; Volume 10, Issue 12 , 2019 ; 2072666X (ISSN) ; Farooq, W. A ; Iftikhar Khan, M ; Niaz Akhtar, M ; Rehman, S. U ; Ahmad, N ; Khalid, M ; Atif, M ; AlMutairi, M. A ; Irfan, M ; Sharif University of Technology
MDPI AG
2019
Abstract
This paper reports on the synthesis of ZnO nanowires (NWs), as well asthe compound nanostructures of nanoparticles (NPs) and nanowires (NWs+NPs) with different coating layers of NPs on the top of NWs and their integration in dye-sensitized solar cells (DSSCs). In compound nanostructures, NWs offer direct electrical pathways for fast electron transfer, and the NPs of ZnOdispread and fill the interstices between the NWs of ZnO, offering a huge surface area for enough dye anchoring and promoting light harvesting. A significant photocurrent density of 2.64mA/cm2 and energy conversion efficiency of 1.43% was obtained with NWs-based DSSCs. The total solar-to-electric energy conversion efficiency...
Green synthesis of Ag–Pt bimetallic nanoparticles supported on the Metal–Organic framework (MOF)–Derived metal oxides (γ-Fe2O3/CuO) nanocomposite as a reusable heterogeneous nanocatalyst and nanophotocatalyst
, Article Materials Chemistry and Physics ; Volume 261 , 2021 ; 02540584 (ISSN) ; Taheri, M ; Gholami, M. R ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
The heterogeneous environmentally friendly catalyst and photocatalyst based on Ag, Pt, Ag–Pt nanoparticles (NPs) loading on the γ-Fe2O3/CuO nanocomposite which was derived from Fe-metal organic framework (Fe-MIL-88B) and Cu-metal organic framework (Cu (tpa)) was introduced. The catalytic and photocatalytic activities of Ag–Pt loading on the γ-Fe2O3/CuO nanocomposite were performed for a reduction process (4-nitrophenol (4-Nip) to 4-aminophenol (4-Amp)), and decomposition organic dyes (AB92, MB) in the LED light. Metal-organic framework (MOFs) composed with inorganic and organic linker which used as suitable precursors to obtain different type of nanostructures for environmental applications....
CuO and ZnO co-anchored on g-C3N4 nanosheets as an affordable double Z-scheme nanocomposite for photocatalytic decontamination of amoxicillin
, Article Applied Catalysis B: Environmental ; Volume 285 , 2021 ; 09263373 (ISSN) ; Hasanvandian, F ; Isari, A. A ; Hayati, F ; Kakavandi, B ; Setayesh, S. R ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In this study, both CuO nanoparticles and ZnO nanorods were anchored on thermally-exfoliated g-C3N4 nanosheets (denoted as CZ@T-GCN) via isoelectric point-mediated annealing process as a novel nano-photocatalyst towards degradation of amoxicillin (AMOX). The features of prepared materials were characterized using BET, UV–vis DRS, XRD, FT-IR, XPS, FE-SEM, TEM, EIS and transient photocurrent techniques. These analyses demonstrated the successful formation of heterojunctions between components of CZ@T-GCN nanocomposite, which reflected in significantly increased electron-hole separation and enhanced degradation of AMOX as compared with pure substances. The investigation of influential operative...
Optimal Ag2S nanoparticle incorporated TiO2 nanotube array for visible water splitting
, Article RSC Advances ; Volume 4, Issue 15 , 2014 , Pages 7838-7844 ; ISSN: 20462069 ; Qorbani, M ; Moradlou, O ; Naseri, N ; Moshfegh, A. Z ; Sharif University of Technology
Abstract
Free-standing TiO2 nanotube array (TNA) films were fabricated via two-step anodization of a titanium sheet. The X-ray diffraction pattern indicated amorphous TNAs were transformed into anatase after annealing the films at 500 °C in air. The surface of TNA was modified by a sequential-chemical bath deposition (S-CBD) method to fabricate Ag2S nanoparticles and forming TNA/Ag2S-n nanostructure, by varying the number of cycles (n). Based on SEM observations, the produced films consisted of vertically ordered tubular structure arrays, each with 125 nm in diameter and 4.1 μm in length containing silver sulphide nanoparticles of ∼12 nm diameter. X-Ray photoelectron spectroscopy (XPS) confirmed the...
Resonant-size spherical bottom scatterers for dye-sensitized solar cells
, Article RSC Advances ; Volume 3, Issue 47 , 2013 , Pages 25417-25422 ; 20462069 (ISSN) ; Taghavinia, N ; Sharif University of Technology
2013
Abstract
We numerically evaluate the effect of a monolayer of resonant-size TiO 2 spheres on the performance of dye-sensitized solar cells (DSCs). This scattering layer is placed between the transparent conducting layer and the dye-sensitized mesoporous TiO2 layer. We carried out our numerical calculations by solving full-wave Maxwell equations in the entire DSC structure using the rigorous coupled-waves approach (RCWA). The layer of TiO2 spheres functions as a strong reflector, leading to strong confinement of the incident light within the absorbing layer of the DSC. The reflectance from this layer originates from coupling of light to the optical resonance modes of the TiO2 spheres. Comparing...
Effect of crystallinity and morphology of TiO2 nano-structures on TiO2 :P3HT hybrid photovoltaic solar cells
,
Article
Applied Solar Energy (English translation of Geliotekhnika)
;
Volume 51, Issue 1
,
January
,
2015
,
Pages 34-40
;
0003701X (ISSN)
; Kasaeian, A. B
; Nikfarjam, A
; Akbarzadeh, A
; Mohammadpour, R
;
Sharif University of Technology
Allerton Press Incorporation
2015
Abstract
A comparative study has been made of hybrid solar cells based on poly(3-hexylthiophene) (P3HT) and different nano-structures of TiO2 . Electrospinning, which is a low cost production method for large area nanofibrous films, was employed to fabricate TiO2 nanofibers and spin coating method was employed to fabricate organic-inorganic hybrid solar cells based on P3HT and TiO2 nanostructures. The performance of the hybrid solar cells was analyzed for four density levels of the TiO2 nanostructure. It was found that higher densities of TiO2 leads to more interface area and generates excitons, so that the power conversion efficiency increases to...
Photoresponse enhancing in nanostructured WO3films by slight change in heating ambient
, Article Journal of Alloys and Compounds ; Volume 693 , 2017 , Pages 871-875 ; 09258388 (ISSN) ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Providing solar hydrogen as a clean energy resource is one of the human challenges for future. Controlling oxygen vacancies as well as surface morphology in metal oxide semiconductors enables developing PEC H2production in some understood ways. Here, the influence of simple change in annealing atmosphere, air and pure oxygen, on photoresponse of nanocrystalline WO3has been studied completely. Results revealed that such slight change in annealing procedure increases effective surface interface and donor density by 77 and 72%, respectively. These effects and also retarding recombination of photogenerated electro-hole pair resulted in photocurrent enhancement under solar like illumination more...
RGO-α-Fe2O3/β-FeOOH ternary heterostructure with urchin-like morphology for efficient oxygen evolution reaction
, Article Journal of Electroanalytical Chemistry ; Volume 843 , 2019 , Pages 1-11 ; 15726657 (ISSN) ; Kowsari, E ; Seifvand, N ; Naseri, N ; Sharif University of Technology
Elsevier B.V
2019
Abstract
RGO-α-Fe2O3/β-FeOOH ternary heterostructure composite has been developed as an active photocatalyst for photoelectrochemical water splitting. RGO-α-Fe2O3/β-FeOOH has been successfully synthesized through one-pot hydrothermal-ionic liquid assisted route using tetrabutyl ammonium L-methioninate [TBA][L-Met]and graphene oxide (GO). The electrochemical studies were carried out to demonstrate the oxygen evolution reaction (OER)and photocatalytic activities. The overpotential reduction by rGO-α-Fe2O3/β-FeOOH sample was higher than the nanobean α-Fe2O3/β-FeOOH and pristine α-Fe2O3 samples. The photocurrent density enhanced for rGO-α-Fe2O3/β–FeOOH urchin-like structure and obtained as 0.62 mA·cm−2....
Effect of Stone-Wales defect on an armchair graphene nanoribbon-based photodetector
, Article Superlattices and Microstructures ; Volume 130 , 2019 , Pages 127-138 ; 07496036 (ISSN) ; Faez, R ; Moravvej Farshi, M. K ; Saghafi, K ; Sharif University of Technology
Academic Press
2019
Abstract
The effect of Stone-Wales (SW) defect on the performance of an armchair graphene nanoribbon (AGNR)-based photodetector is studied. To model the SW defect two new tight-binding (TB) parameters are proposed that provide results that are in good agreement with density functional theory calculations. SW defect is introduced in different locations in the channel of the AGNR detector and the photocurrent, quantum efficiency and responsivity of defected structures are calculated using TB approximation and non-equilibrium Green's function formalism. By inspecting the photo-generated hole density in different points of the channel, the way that photocurrent is affected by SW defect in different...
An ultrathin amorphous defective co-doped hematite passivation layer derived via an in situ electrochemical method for durable photoelectrochemical water oxidation
, Article Journal of Materials Chemistry A ; Volume 10, Issue 31 , 2022 , Pages 16655-16665 ; 20507488 (ISSN) ; Qorbani, M ; Sabbah, A ; Quadir, S ; Huang, C. Y ; Chen, K. H ; Chen, L. C ; Naseri, N ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
Although hematite (i.e., α-Fe2O3) has been widely investigated in photoelectrochemical water oxidation studies due to its high theoretical photocurrent density, it still suffers from serious surface charge recombination and low photoelectrochemical stability. Here we report an in situ electrochemical method to form a uniform and ultrathin (i.e., 3-5 nm) passivation layer all over the pores of an optimized ∼3.2% Ti-doped α-Fe2O3 photoanode. We unveil the amorphous and defective nature of the in situ derived layer assigned to a high concentration of oxygen vacancies and intercalated potassium atoms there, i.e., the formation of Ti/K co-doped defective α-Fe2O3−x. Owing to the efficient...
A comparative study on photoelectrochemical activity of ZnO/TiO2 and TiO2/ZnO nanolayer systems under visible irradiation
, Article Solar Energy ; Volume 85, Issue 9 , 2011 , Pages 1972-1978 ; 0038092X (ISSN) ; Yousefi, M ; Moshfegh, A. Z ; Sharif University of Technology
Abstract
TiO2/ZnO and ZnO/TiO2 nanolayer thin films were synthesized using sol-gel method. Optical analysis revealed high transmittance of the films in the visible range with almost the same bandgap energy for the both systems. XPS technique shows stoichiometric formation of TiO2 and ZnO on the surface of TiO2/ZnO and ZnO/TiO2 layers, respectively. According to AFM observations and its data analysis, the TiO2/ZnO films exhibited a higher surface roughness and more effective interfaces with electrolyte during redox reactions. Based on photoelectrochemical measurements, TiO2/ZnO nanolayer photoanode possesses a lower charge transfer resistance and higher transient time for charge carriers (e- and h+)...
Stable and efficient CuO based photocathode through oxygen-rich composition and Au-Pd nanostructure incorporation for solar-hydrogen production
, Article ACS Applied Materials and Interfaces ; Volume 9, Issue 33 , 2017 , Pages 27596-27606 ; 19448244 (ISSN) ; Siavash Moakhar, R ; Chua, C. S ; Kushwaha, A ; Dalapati, G. K ; Sharif University of Technology
Abstract
Enhancing stability against photocorrosion and improving photocurrent response are the main challenges toward the development of cupric oxide (CuO) based photocathodes for solar-driven hydrogen production. In this paper, stable and efficient CuO-photocathodes have been developed using in situ materials engineering and through gold-palladium (Au-Pd) nanoparticles deposition on the CuO surface. The CuO photocathode exhibits a photocurrent generation of ∼3 mA/cm2 at 0 V v/s RHE. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis and X-ray spectroscopy (XPS) confirm the formation of oxygen-rich (O-rich) CuO film which demonstrates a highly stable photocathode with retained...