Fig 2 - available via license: Creative Commons Attribution 4.0 International
Content may be subject to copyright.
Atomic force microscopy (AFM) images of Lu 2 O 3 (a) pristine (b) annealed and TiO 2 terminated STO (c) pristine (d) annealed.
Source publication
Understanding the structural, physical and chemical properties of the surface and interfaces of different metal-oxides and their possible applications in photo-catalysis and biology is a very important emerging research field. Motivated in this direction, this article would enable understanding of how different fluids, particularly water, interact...
Contexts in source publication
Context 1
... Fig. 2 we have shown the root mean square (rms) Fig. 2(a)] to 0.53 nm [ Fig. 2(b)] before and aer annealing respectively. Similarly the surface roughness of TiO 2 terminated SrTiO 3 single crystal varies from 0.15 nm [Fig. 2(c)] to 3.01 nm [ Fig. 2(d)] before and aer annealing respectively. In TiO 2 terminated SrTiO 3 single crystal samples ...
Context 2
... Fig. 2 we have shown the root mean square (rms) Fig. 2(a)] to 0.53 nm [ Fig. 2(b)] before and aer annealing respectively. Similarly the surface roughness of TiO 2 terminated SrTiO 3 single crystal varies from 0.15 nm [Fig. 2(c)] to 3.01 nm [ Fig. 2(d)] before and aer annealing respectively. In TiO 2 terminated SrTiO 3 single crystal samples AFM images of the pristine samples [Fig. 2(c)] ...
Context 3
... Fig. 2 we have shown the root mean square (rms) Fig. 2(a)] to 0.53 nm [ Fig. 2(b)] before and aer annealing respectively. Similarly the surface roughness of TiO 2 terminated SrTiO 3 single crystal varies from 0.15 nm [Fig. 2(c)] to 3.01 nm [ Fig. 2(d)] before and aer annealing respectively. In TiO 2 terminated SrTiO 3 single crystal samples AFM images of the pristine samples [Fig. 2(c)] clearly showing the atomic ...
Context 4
... Fig. 2 we have shown the root mean square (rms) Fig. 2(a)] to 0.53 nm [ Fig. 2(b)] before and aer annealing respectively. Similarly the surface roughness of TiO 2 terminated SrTiO 3 single crystal varies from 0.15 nm [Fig. 2(c)] to 3.01 nm [ Fig. 2(d)] before and aer annealing respectively. In TiO 2 terminated SrTiO 3 single crystal samples AFM images of the pristine samples [Fig. 2(c)] clearly showing the atomic step-edges which is gone aer high pressure annealing [ Fig. 2(d)]. Value of all this surface roughness is very low, all of them are below 5 nm for ...
Context 5
... Fig. 2 we have shown the root mean square (rms) Fig. 2(a)] to 0.53 nm [ Fig. 2(b)] before and aer annealing respectively. Similarly the surface roughness of TiO 2 terminated SrTiO 3 single crystal varies from 0.15 nm [Fig. 2(c)] to 3.01 nm [ Fig. 2(d)] before and aer annealing respectively. In TiO 2 terminated SrTiO 3 single crystal samples AFM images of the pristine samples [Fig. 2(c)] clearly showing the atomic step-edges which is gone aer high pressure annealing [ Fig. 2(d)]. Value of all this surface roughness is very low, all of them are below 5 nm for both SrTiO 3 single ...
Context 6
... square (rms) Fig. 2(a)] to 0.53 nm [ Fig. 2(b)] before and aer annealing respectively. Similarly the surface roughness of TiO 2 terminated SrTiO 3 single crystal varies from 0.15 nm [Fig. 2(c)] to 3.01 nm [ Fig. 2(d)] before and aer annealing respectively. In TiO 2 terminated SrTiO 3 single crystal samples AFM images of the pristine samples [Fig. 2(c)] clearly showing the atomic step-edges which is gone aer high pressure annealing [ Fig. 2(d)]. Value of all this surface roughness is very low, all of them are below 5 nm for both SrTiO 3 single crystal and Lu 2 O 3 thin-lm samples. This amount of morphological change cannot explain the signicant change we observe in WCA value. XRD ...
Context 7
... the surface roughness of TiO 2 terminated SrTiO 3 single crystal varies from 0.15 nm [Fig. 2(c)] to 3.01 nm [ Fig. 2(d)] before and aer annealing respectively. In TiO 2 terminated SrTiO 3 single crystal samples AFM images of the pristine samples [Fig. 2(c)] clearly showing the atomic step-edges which is gone aer high pressure annealing [ Fig. 2(d)]. Value of all this surface roughness is very low, all of them are below 5 nm for both SrTiO 3 single crystal and Lu 2 O 3 thin-lm samples. This amount of morphological change cannot explain the signicant change we observe in WCA value. XRD technique was used to study the effect of annealing on the structural properties of these ...
Context 8
... the in- gap state produce a radiative process that results in blue-light emission. 34 Also here in Fig. 5 we nd a similar trend which clearly indicates that with increasing annealing time more oxygen vacancies are created in our SrTiO 3 substrates. water contact angle comes out to be much lower (59.6 ). XPS spectra collected in the C 1s region (Fig. S2 †) show no signicant change upon annealing, suggesting that the change in contact angle is not due to the formation (or removal) of surface carbonates. A very similar behaviour of WCA upon annealing is also found on another REO thin-lm system of CeO 2 [see 'ESI' Fig. S3 for the details ...
Similar publications
The purpose of this article is to investigate the effect of the wettability on the thermal conductivity of microencapsulated phase change material suspensions. The wettability of the capsules, characterized by contact angle between solid capsules and carrier fluid, was modified by mixing two selected surfactants into the suspensions, that is, cetyl...
New strategies for the fabrication of surface structures using Direct Laser Interference Patterning are presented in this work, aiming to fabricate hierarchical structures with selective wetting properties. Polycarbonate sheets have been structured employing a two-beam interference arrangement using an ultraviolet (263 nm) nanosecond-pulsed laser,...
Surfaces of optical elements are deposited by antireflection coatings (ARCs) to
decrease the reflection of light. Surface needs treatment before depositing the
ARC one of treatment processes by plasma for adhesion improvement and
surface hardening. A comparison of RF and DC glow discharges treated
CR-39 polymer films gives insight into the mechanis...
The influence of the external pressure and surface energy on the wetting transition at nanotextured interfaces is studied using molecular dynamics and continuum simulations. The surface roughness of the composite interface is introduced via an array of spherical nanoparticles with controlled wettability. We find that in the absence of an external p...
The current study examines the synergy of interfacial tension, emulsification, wettability alteration and extent of saponification during alkali flooding for light to moderate crude oil. The oil recovered in the effluent stream during NaOH flooding was analysed to observe the quality of water in oil (W/O) emulsion produced and the extent of saponif...
Citations
... However, as presented in Figure 6f, the AR of the V2O5−x islands gradually decreased only until 75 °C, after which it increased again at higher temperatures (i.e., 100 and 125 °C). On the basis of this behavior, we assume that the nucleation rate for the V2O5−x would decrease at temperatures above 75 °C, at which more metallic V-rich V2O5−x islands would form to increase the AR [40,41]. To confirm this assumption, additional XPS measurements were performed to investigate the stoichiometry of the V2O5−x TFs deposited at different temperatures and the results are presented in Figures 8 and 9. ...
... However, as presented in Figure 6f, the AR of the V 2 O 5−x islands gradually decreased only until 75 • C, after which it increased again at higher temperatures (i.e., 100 and 125 • C). On the basis of this behavior, we assume that the nucleation rate for the V 2 O 5−x would decrease at temperatures above 75 • C, at which more metallic V-rich V 2 O 5−x islands would form to increase the AR [40,41]. To confirm this assumption, additional XPS measurements were performed to investigate the stoichiometry of the V 2 O 5−x TFs deposited at different temperatures and the results are presented in Figures 8 and 9. ...
In recent decades, dopant-free Si-based solar cells with a transition metal oxide layer have gained noticeable research interest as promising candidates for next-generation solar cells with both low manufacturing cost and high power conversion efficiency. Here, we report the effect of the substrate temperature for the deposition of vanadium oxide (V2O5−x, 0 ≤ X ≤ 5) thin films (TFs) for enhanced Si surface passivation. The effectiveness of SiOx formation at the Si/V2O5−x interface for Si surface passivation was investigated by comparing the results of minority carrier lifetime measurements, X-ray photoelectron spectroscopy, and atomic force microscopy. We successfully demonstrated that the deposition temperature of V2O5−x has a decisive effect on the surface passivation performance. The results confirmed that the aspect ratio of the V2O5−x islands that are initially deposited is a crucial factor to facilitate the transport of oxygen atoms originating from the V2O5−x being deposited to the Si surface. In addition, the stoichiometry of V2O5−x TFs can be notably altered by substrate temperature during deposition. As a result, experimentation with the fabricated Si/V2O5−x heterojunction solar cells confirmed that the power conversion efficiency is the highest at a V2O5−x deposition temperature of 75 °C.
... Presence of oxides such as TiO 2 and Nb 2 O 5 has been reported to improve the surface hydrophilicity [53,54]. The oxygen present in water is capable of healing the surface oxygen vacancies generated by the Ti 3+ state and the two H atoms form chemisorbed OHgroups with surface O atoms [55]. This generation of polar hydroxyl groups increases the Van der Waals forces and the hydrogen-bonding interactions, thereby stabilizing surface wettability by generating oxygen bonds with subsequent water layers in the case of LP-6 and LP-9 GW/cm 2 [56]. ...
This paper reports the effect of varying laser-peening fluences (3, 6 and 9 GW/cm²) on surface topography, oxide composition and wettability of low modulus Ti-22Nb at.% (Ti-35.4Nb wt.%) alloy with specific focus on the ensuing fretting wear and biocompatibility. Microtopography with nano-sized pores were generated during the laser interaction. LP-6 and LP-9 GW/cm² surfaces displayed nano-porous distribution, with topographies characterized by negative skewness and platykurtosis. X-ray photoelectron studies revealed the development of mixed oxide layers rich in Ti⁴⁺ and Nb⁵⁺ when laser fluence was increased. Improved hydrophilic behavior was observed with increment in laser fluence displaying contact angles of 47.1° and 43.2° for LP-6 and LP-9 GW/cm². Based on the preliminary surface characterizations, LP-6 and LP-9 GW/cm² which displayed a platykurtic surface with negative skewness, Ti-Nb based mixed oxides and stable hydrophilic nature were selected for further analysis. Presence of Nb⁵⁺ ions rendered the oxide surfaces less defective, thereby improving fretting wear resistance. In particular, well-spread cells and up-regulation of beneficial genetic-markers (Ki67) on laser-peened surfaces demonstrated the role of nano-sized cues and oxide-layer in improving osseointegration aspects. Results demonstrate that LP-6 and LP-9 GW/cm² surfaces on low modulus Ti-22Nb alloy can beneficially contribute towards the fretting wear and biocompatibility.
... These oxygen vacancies in Tungsten Oxide tend to adsorb water molecules because the located electrons in this state affect surface adsorption and reactivity of adsorbents such as water or oxygen on the oxide (Thompson and Yates, 2005;Pan et al., 2013). The adsorption of water molecules creates an electrolytic film on the crystal surface (Sarkar et al., 2016;Sun et al., 2001;Shen et al., 2018). This hydrophilic film will attract water molecules, thereby enhance membranes hydrophilicity and pure water flux when the nanoparticles are present in the membrane matrix. ...
Merging the photocatalytic activity of nanomaterials with membrane technology is an auspicious approach towards diminishing membrane fouling consequences. Herein, 0.1 to 2 wt.% of Tungsten Oxide (WO2.89) were harnessed to synthesis novel mixed matrix nanocomposite ultrafiltration membranes via the classical noninduced phase separation. A systematic comprehensive characterization was conducted to probe the additive influence on the ultimate characteristics of the UF nanocomposites. This comprised membranes morphology, chemical structure, mechanical properties, hydrophilicity, and their performance against Congo red (CR) dye. Results manifested that greater water flux along with higher hydrophilicity and water uptake capacity was achieved at 0.4 WO2.89 loading weight %. Under an hour of UV light irradiation, the flux recovery ratio of the 0.4 wt.% nanocomposite membranes was 83.3% compared to 71.5% for the control UF membrane. Meanwhile, pore blockage was realized at a higher additive ratio due to agglomeration occurrence, causing greater dye rejection, roughness, contact angle, and inducing lower permeate flux and flux recovery ratio. In the presence of WO2.89 nanoparticles, dye degradation has hit the 86% level after only 30 minutes of UV irradiation. Exposing the nanocomposite membranes to UV irradiation has induced a further enhancement in the FRR of the membranes. Decomposition of the organic molecules by WO2.89 nanoparticles photocatalytic activity on/near the membrane surface was the major factor to bring about this enhancement. Ultimately, the photocatalytic activity of the nanocomposites prepared in the current work could open new insights towards their application for wastewater treatment applications.
... In the case of H 2 :TiO 2 /WO 3 @Pt this hydrophilic conversion with WCA Dark /WCA light : 47 • : 8 • is more significant than others. As the light is turned off, all non-hydrogen-treated samples return back to their initial WCA while the ones subjected to hydrogen treatment keep their wettability for hours in the dark, probably due to higher contents of oxygen vacancies resulting from hydrogen treatment [86][87][88]. ...
For the first time this work reports a new idea to develop a round-the-clock self-cleaning coating which was successfully applied to preserve cultural heritage and modern artifacts under sunlight illumination and at night. To fabricate this structure, namely, H2:TiO2/ WO3@Pt, soft templating and hydrogen treatment approaches were selected to enhance the performance of TiO2/WO3 photocatalyst, together with the addition of Pt plasmonic nanoparticles. The coating can be photochemically charged in the presence of sacrificial electron donors and keep its stability, benefiting from the remained electrons stock for over 10 hours to clean the surface from aggressive pollution also at night, in absence of light. This transparent heterostructure with high surface area, proper interfacial contacts in TiO2/WO3@ Pt system, and extended visible light absorption resulting from the synergistic interactions of the composite system (TiO2, WO3, and Pt) presents an efficient self-cleaning performance. The smart coated surface could clean the substrate benefiting from 70% pollutants photodegradation after irradiation followed by dark storage (2 and 6 h, individually), and superhydrophilic properties were maintained for hours in the dark, thanks to oxygen vacancies resulted from hydrogen treatment.
... In addition, the creation of surface defect sites after oxidation enhances the water wettability of nanosheets [34]. The contact angle measurement exhibited improvement in surface hydrophilicity of CuBi-PE HFGDE after thermal oxidation (Fig. S8), confirming the efficacy of thermal treatment to maximize three-phase interface formation. ...
Gas-phase CO2 electrochemical reduction reaction (CO2RR) requires advanced gas diffusion electrodes (GDEs) for efficient mass transport. Meantime, engineering catalyst nanostructure and tuning surface wettability are decisive to enhance three-phase interfaces formation. Herein, Bi-based nanosheets are uniformly grown on flow-through Cu hollow fiber GDE (HFGDE) to benefit from the unique shape of HFGDEs, and abundant active surface area of nanosheets. Pulse electrodeposition is used to replenish Bi³⁺ ions in the vicinity of HFGDEs for uniform growth of Bi nanosheets. Further, thermal oxidation of nanosheets not only maximized the active sites and improved surface wettability but also induced Bi/Bi2O3 junctions in nanosheets, enhancing formate production via switching the rate-limiting step from the initial electron transfer to hydrogenation. Consequently, a current density of 141 mA cm⁻² at -1 V vs. RHE with formate faradaic efficiency of 85% and over six times greater catalyst mass activity compared to bulk particle shaped Bi, were achieved, outperforming other reported Bi-based GDEs used for formate production in bicarbonate electrolytes. This comes from less charge-transfer resistance, higher surface roughness, and improved wettability of Bi nanosheets after oxidation. This work represents a facile strategy to engineer efficient HFGDEs as advanced electrode materials for similar electrochemical reactions with low aqueous solubility gas-phase feeds.
... At first observation, as evident from the RBS study (see SM [29]), the surface layer is found to be Sr 0.95 TiO 2.98 . Since the thin-film fabrication with perfect stoichiometric composition and uniform thickness is a big challenge, any slight deviation causes change in the value of t 2g /e g ratio [58]. There are some detailed reports understanding the Ti L-edge spectra using Multiplet calculations [59,60]. ...
The present study utilizes synchrotron-based x-ray diffraction (XRD), photoluminescence (PL), and x-ray absorption near edge structure (XANES) spectroscopic techniques to comprehend the evolution of optical intense blue-green emission in 100 keV nitrogen (N) ion implanted SrTiO3 (STO) thin films deposited by RF magnetron sputtering technique. The XRD pattern shows a shift in reflections at lower N ion fluences and the amorphization of the films at higher fluences. A disordered phase induced by implantation in the STO films leads to an intense blue-green emission due to oxygen (O) vacancies and N (2p) bound states. A schematic diagram of energy levels has been proposed to explain the origin of PL emission. The XANES spectra at Ti K edge reflect a change in the valency of Ti ions and the local atomic structure of ordered and disordered phases of STO with an increase in N ion fluence. The splitting of peak assigned to eg orbitals, and discrepancy in ratio dz2/dx2−y2 observed in the Ti L- and O K-edge spectra, confirm a distortion in TiO6 octahedral structure and modifications in O 2p-Ti 3d hybridization states. The synchrotron-based techniques reveal that N ion implanted STO can be a good photoluminescent material exhibiting a variety of emissions through bound states of O vacancies and implanted N ions.
... Our goal was to remove the hydrocarbon adsorbents to give an increased surface wettability that assists the formation of ultra-smooth spin-coated films (root-mean-square roughness < 0.8 nm for 25 × 25 mm 2 ). This technique is widely used in contact angle studies 48,49 and also in the fabrication of organic light-emitting diodes 50,51 . ...
Electronic symmetry breaking by charge disproportionation results in multifaceted changes in the electronic, magnetic and optical properties of a material, triggering ferroelectricity, metal/insulator transition and colossal magnetoresistance. Yet, charge disproportionation lacks technological relevance because it occurs only under specific physical conditions of high or low temperature or high pressure. Here we demonstrate a voltage-triggered charge disproportionation in thin molecular films of a metal–organic complex occurring in ambient conditions. This provides a technologically relevant molecular route for simultaneous realization of a ternary memristor and a binary memcapacitor, scalable down to a device area of 60 nm². Supported by mathematical modelling, our results establish that multiple memristive states can be functionally non-volatile, yet discrete—a combination perceived as theoretically prohibited. Our device could be used as a binary or ternary memristor, a binary memcapacitor or both concomitantly, and unlike the existing ‘continuous state’ memristors, its discrete states are optimal for high-density, ultra-low-energy digital computing.
... Less wettable (i.e. less hydrophilic or more hydrophobic) ETL is highly desirable for PSC devices as it would improve the resistance of the sample towards humidity and ultimately enhance the long-term stability of PSC. Wettability of a surface could be influenced by the surface roughness, crsytallinity and presence of oxygen vacancies [55][56][57][58][59][60][61]. It has been reported that greater amount of oxygen vacancies would increase the hygroscopic nature of particular metal oxide layer which in turn reduces the value of water contact angle. ...
... The presence of oxygen vacancy encourages dissociative adsorption of water at the vacancy sites. This is due to the fact that the single oxygen atom of water heals the vacancy, while the other two hydrogen atoms bind to the oxygen atoms on the surface of metal oxide to form hydroxyl groups [55,56]. Since the hydroxyl groups that were created on the film surface are polar molecules, they are able to form oxygen bonds with the subsequent water molecules which consequently promotes the surface hydrophilicity of metal oxide [17]. ...
Metal oxide-based electron transport layer (ETL) is one of the vital components in conventional n-i-p type perovskite solar cells (PSC) that enables efficient electron extraction and transport within the device. Nonetheless, native point defect associated with oxygen vacancies that naturally exist in the ETL materials such as TiO2, SnO2 and Nb2O5 could deteriorate the overall performance of the PSC. In this chapter, the intentional and unintentional formation of oxygen vacancies during the fabrication process of the ETL will be firstly clarified. The properties of oxygen vacancies in the viewpoint of structural, optical and electrical as well as surface wettability will also be profoundly elaborated to provide valuable insight on the impact of oxygen vacancies in the ETL towards efficiency, hysteresis and stability of PSC devices.
... Moreover, the increased surface roughness of nanostructured SnO 2-x resulted in the decrease in the contact angle, which is in accordance with the Wenzel theory (no air bubbles are trapped within nanochannels) [52]. Additionally, the presence of eOH groups at the surface may be also responsible for the hydrophilic behavior of the materials [53]. Further, a brief comparison of water CAs of as-received porous SnO 2-x layers synthesized at both potentials reveals that the anodic film formed at 4 V, which is thicker and has much wider channels and more Sn 2þ defects, is slightly less hydrophilic compared to that obtained at 2 V. ...
... This phenomenon may be connected to the coexistence of the different phases of tin oxides, which was proven to be responsible for the enhanced wettability when RF-sputtered SnO films (annealed at 500 C) were tested [54]. What is more, the decrease in the wettability may be also caused by the presence of oxygen vacancies that are "healed" by water molecules [53]. Finally, the presence of eOH groups on the oxide surface combined with annealing in air at higher temperatures may lead to the formation of the van der Waals bonds between the surface and water molecules, thus providing superhydrophilic behavior of the substrates [50]. ...
In this work, the effect of the thermal annealing on the composition of crack-free anodic tin oxide layers with different channel diameters, formed in 1 M NaOH at 2 and 4 V, was investigated in detail. STEM tomography confirmed that anodic oxides formed at 2 V have narrower channels, higher porosity, and higher surface area than those anodized at 4 V. Structural properties of oxides films were studied using different techniques such as X-ray diffraction, Raman spectroscopy, and UV-Vis diffuse reflectance spectroscopy. In addition, Raman imaging was employed to study local changes in the composition of anodic films. The photoelectrochemical performance of as-formed and annealed oxides was correlated with applied anodizing potential and annealing conditions. It was found that as-formed anodic oxides are composed of poorly crystalline SnO2-x with a significant amount of Sn²⁺ defects. When the oxide layers were annealed at 200 °C, crystallization of the SnO phase was observed, however, the amount of Sn²⁺ defects was not drastically reduced. A significant reduction of Sn²⁺ defects occurred at 400 °C due to a formation of intermediate Sn3O4 oxide and, in the final result, more stoichiometric and crystalline SnO2 was formed. We proved that appropriate design of anodizing and annealing procedures can lead to the formation of nanoporous tin oxide layers with controlled morphology, composition and, in consequence, photoelectrochemical properties.
... These promising properties can be obtained by appropriate surface treatments [1][2][3][4][5][6][7]. Several investigations were performed recently to elaborate such surfaces and understand the wettability behavior [8][9][10] and the superhydrophobicity regime on various substrates: metal oxide [11][12][13], rare earth oxides [14][15][16] and SiNWs [17][18][19][20][21][22]. However, a few works was devoted to the study of hydrophobicity property of Ni-Co oxide based films [23][24][25][26]. ...
In this work, superhydrophobic nickel cobalt hydroxide films were electrodeposited on silicon nanowires array (SiNWs). The superhydrophobicity was attributed to the morphology of NiO-Co(OH)2 which was deposited as urchin–like structures composed of many nanorods radially grown from the center. It was observed that the wettability decreases as these surfaces were irradiated with visible light. Indeed, the contact angle decreases from 158° to 7° after 1 h of visible light illumination. This behavior has allowed to improve the photocatalytic efficiency during the photodegradation process of rhodamine B (RhB). A full degradation was achieved after 1 h of visible light irradiation.
