Multifunctional thin films are becoming extremely popular in many technological fields. An increase in their functionality can be achieved by the creation of nanocomposite structures. This study ...represents novel thin composite coatings with a horizontally oriented single-walled carbon nanotube (SWCNT) filler inside a silicon oxynitride (SiOxNy) matrix obtained by (i) low-temperature thermal curing or by (ii) UV radiation-induced curing. The SiOxNy/SWCNT composite structures were prepared by simple dry transfer of a SWCNT film into a perhydropolysilazane (PHPS) polymer matrix film deposited by the spin-coating technique followed by curing. The structural, morphological, and optical properties of the SiOxNy/SWCNT composite films were studied using HR-SEM/EDX, ATR-FTIR, and UV–Vis spectroscopy. It was found that SWCNT films were uniformly transferred into the PHPS matrix, maintaining their horizontally oriented close-packed structure, and avoiding the problem of agglomeration, thereby forming a laminate-type composite. SWCNTs had no effect on the curing process of the PHPS matrix. The SWCNT concentration remained relatively low, resulting in highly transparent composite films. An antireflection effect in the composite film relative to the transmission of the SWCNT film was observed. The results indicate that SiOxNy/SWCNT composites are attractive for applications as protective, antireflective optical coatings.
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•Synthesis of transparent TiO2 thin films functionalised with silver NPs for photocatalytic and antimicrobial surfaces.•The synthesis methodologies used, such as spray pyrolysis and ...pulsed laser ablation (PLAL), have a wide industrial application.•The addition of silver NPs on the TiO2 surface improves the photocatalytic and antimicrobial properties.•Photocatalytic tests confirm that these thin films could be used to degrade pollutants such as Rhodamine B by UV light.
Transparent TiO2 thin films coated with Ag NPs were synthesized using two industrially applicable techniques,pulsed laser ablation (PLAL) and spray pyrolysis without using high vacuum. These transparent thin films were deposited on glass in order to generate glass materials with photocatalytic and antimicrobial properties and a minimum loss of transparency. The structural, morphological and optical properties of the thin films were examined using Grazing incidence X-ray diffraction (GIXRD), Raman spectroscopy, Scanning electron microscopy (SEM) and ultraviolet–visible spectroscopy. Transmission electron microscopy (TEM) was used to identify the NPs on the TiO2 surface. The transmittance value for the thin films was greater than 80%.The thin films thus synthesized were then assessed to determine their photocatalytic capacity by monitoring the degradation of Rhodamine B (RhB) under UV light irradiation. Ag NPs on the TiO2 surface ensures an improvement in the photocatalytic properties, with a 99% degradation of RhB in 210 min under UV light. In addition, these transparent thin films showed high antimicrobial activity on Gram-negative bacteria when irradiated by UV light for 4 h, killing 93% of these bacteria.
ZnO is known as a wide-bandgap transparent thermoelectric material. Herein, the electronic transport and temperature-dependent thermoelectric properties of transparent Sb-doped ZnO (SZO) films are ...reported. The sputtered SZO films prepared at the optimum deposition temperature of 673 K show an n-type semiconducting behavior with the highest thermoelectric power factor of 406 μW/mK2 at 773 K, and a good transmittance ∼82% in the wavelength region of 400–1100 nm. It can well meet the requirements for transparent thermoelectric thin films. Through X-ray diffraction, UV–Vis, and photoluminescence analyses, the Zn2+ substitution by Sb5+ can be elucidated for significantly enhancing the Seebeck coefficient and thermoelectric power factor due to the increase of density-of-state effective mass.
•Transparent thermoelectric thin films have a large potential for hybrid thermoelectric-photovoltaic applications.•Sb doping shows a significant improvement in thermoelectric properties of sputtered ZnO thin films.•An increase of DOS effective mass significantly increases Seebeck coefficient with elevating deposition temperature.•At the optimum deposition temperature of 673 K, the Sb-doped ZnO films obtain the highest PF of 406 μW/mK2 at 773 K.
•Hydrogenated amorphous silicon carbonitride deposition at low temperature.•Correlation between gas phase chemistry and thin-film composition.•Correlation between thin-film composition and optical ...properties.•Trade-off between optical gap and refractive index for optical materials selection.
a-SiCN:H thin films were deposited at 150°C by PECVD using silane, methane and ammonia as precursor gases, with a SiH4:H2 dilution of 1:9. RBS and ERDA were used for determining material composition. The concentration of silicon, carbon and nitrogen in the deposited films was correlated with the respective precursor gas concentration and the incorporation yield of each atomic species was determined and related to the molecular bond energies of precursor gases. Chemical bonding type and density determined by FTIR were also related to the chemical composition of the films. Optical transmission was measured to estimate the optical gap (Eop) and refractive index (n) in the transparent region. Stoichiometric a-SiN has the lowest n (1.74) and highest Eop (4.12 eV) while a-Si:H presents the highest n (3.37) and lowest Eop (1.85 eV). A trade-off between the Eop and n is presented to show the applicability of this ternary material in optical devices.
In this paper, mesoporous antimony doped tin oxide (ATO) microspheres are synthesized via a solvothermal method from a methanol system with the surfactant followed by a thermal treatment process. ...Morphology studies reveal that the spherical products obtained by polyvinylpyrrolidone (PVP) templating result in a higher uniformity in size. Such obtained ATO microspheres with a secondary particle size ranging between 200 and 800 nm consist of packed tiny nanocrystals and have high specific surface area (∼98 m2 g–1). The effect of Sb doping on the structural and electrical properties of SnO2 microspheres is studied. Because of the substitution of Sn4+ with Sb5+ accompanied by forming a shallow donor level close to the conduction band of SnO2, a lower resistivity of powder pellet can be achieved, which corresponds to the spectrally selective property of films. The application of ATO microspheres provides an example of transparent coatings; depending on Sb concentration in SnO2 and solid content of coatings, transparent films with tunable solar-heat shielding property are obtained.
Electronic devices that are transparent and flexible have a wide range of applications in the domains of vital sign parameter monitoring, health management, and so on. Ferroelectric memory is a ...revolutionary nonvolatile memory that is ideal for data storage and processing in transparent flexible electronic systems. In this study, Ce-doped hafnium oxide ferroelectric thin film is manufactured on mica substrate by the chemical solution deposition with transparent indium tin oxide (ITO) thin films as the bottom electrodes. The transmittance of mica/ITO/Hf
0.85
Ce
0.15
O
2
thin film is over 80%. The 2P
r
of the transparent flexible Hf
0.85
Ce
0.15
O
2
ferroelectric thin film is increased by about 22.4% and the
E
c
is reduced by 26.7% compared with those of Hf
0.85
Ce
0.15
O
2
ferroelectric thin film grown on p+-Si substrate. The transparent flexible Hf
0.85
Ce
0.15
O
2
ferroelectric thin film can remain keeping good quality when being bent under ±2.5 mm bending radius. Additionally, degradation of polarization, retention, and endurance performance was not obvious even at a bending radius of 5.0 mm after 10
4
bending cycles. This research provides a new strategy and an important experimental basis for the development and implementation of transparent flexible ferroelectric memories.
Attaining aqueous solutions of individual, long single-walled carbon nanotubes is a critical first step for harnessing the extraordinary properties of these materials. However, the widely used ...ultrasonication–ultracentrifugation approach and its variants inadvertently cut the nanotubes into short pieces. The process is also time-consuming and difficult to scale. Here we present an unexpectedly simple solution to this decade-old challenge by directly neutralizing a nanotube-chlorosulfonic acid solution in the presence of sodium deoxycholate. This straightforward superacid-surfactant exchange eliminates the need for both ultrasonication and ultracentrifugation altogether, allowing aqueous solutions of individual nanotubes to be prepared within minutes and preserving the full length of the nanotubes. We found that the average length of the processed nanotubes is more than 350% longer than sonicated controls, with a significant fraction approaching ∼9 μm, a length that is limited by only the raw material. The nondestructive nature is manifested by an extremely low density of defects, bright and homogeneous photoluminescence in the near-infrared, and ultrahigh electrical conductivity in transparent thin films (130 Ω/sq at 83% transmittance), which well exceeds that of indium tin oxide. Furthermore, we demonstrate that our method is fully compatible with established techniques for sorting nanotubes by their electronic structures and can also be readily applied to graphene. This surprisingly simple method thus enables nondestructive aqueous solution processing of high-quality carbon nanomaterials at large-scale and low-cost with the potential for a wide range of fundamental studies and applications, including, for example, transparent conductors, near-infrared imaging, and high-performance electronics.
Flexible and transparent conductive (FTC) thin films are indispensable elements in building high‐performance flexible or soft electronics and displays. Slim inorganic nanowires (NWs), with excellent ...conductivity and durability, are ideal one‐dimensional ingredients to weave a quasi‐continuous FTC network. However, a precise spatial arrangement of these ultrathin NWs, to form an optimal interconnected network, represents still a difficult challenge. In this work, a catalytic growth of orderly SiNW arrays, via an in‐plane solid‐liquid‐solid mechanism, and an orthogonal‐stacking integration of the SiNWs into a 2‐layer cross‐linked network, followed by a direct alloy formation and soldering of highly conductive SiNi alloy NWs upon a flexible polyimide polymer, is demonstrated. It is also shown that the flexibility of the SiNi FTC network can be significantly enhanced with an elastic spring design of the silicide NW channels, leading to an impressive transmittance of ≈90%, a moderately equivalent sheet resistance of 130 Ω sq−1 and a durable flexibility that can sustain repetitive bending to a 2 mm radius for >1000 cycles. These results highlight the unique capabilities of an optimal spatial arrangement, precise assembly/soldering and elastic geometry design of alloy NWs to enable a new generation of high‐performance FTC thin film material for future flexible electronics, displays, and bio‐interfaced sensors.
An orthogonal‐stacking integration of elastic SiNi alloy nanowire into a 2‐layer cross‐linked network is demonstrated upon a flexible polyimide substrate, with high optical transmittance of ≈90%, sheet resistance of 130 Ω sq‐1 and excellent flexibility that can sustain 1000 cycles bending radius to 2 mm, making them ideal flexible and transparent conductive thin films for high‐performance flexible electronics, displays and bio‐interfaced sensors.
Dye-sensitized solar cell (DSSC) is the most promising of third generation solar cells for large scale applications due its low cost, flexibility, and scalable manufacturability. However, enhancing ...the efficiency of the DSSC is still highly desired. In this study, we designed a novel bifacial DSSC based on a transparent Polyaniline (PANI) films as counter electrode (CE) associated with coral-like TiO2 nanostructured films, which can be used as the photoanode. PANI-based CEs were prepared by a facile in situ polymerization, while coral-like TiO2 films were chemically synthesized at low temperature through the sol–gel process. Owing to the light irradiation from both the front and the rear sides, it is expected that higher density of dye molecules should be excited. In addition, due to the excellent light scattering of the coal-like TiO2 and high specific surface area of PANI nanofibers (NFs), more carriers are generated. Both these factors resulted in the increase of the conversion efficiency. The bifacial DSSC fabricated by combining the PANI NFs-based film and the coral-like TiO2 film in the presence of the expensive N719 dye molecules showed the efficiency of 8.22% corresponding to the both-side irradiation. In comparison, similar cells employing either a cross-linked PANI- or Pt-based CE showed efficiencies of 7.81% and 7.75%, respectively. The results of the similar cells in the presence of the low cost CoPC dye molecules showed efficiencies of 0.29%, 0.22%, and 0.27%, for DSSCs comprised of PANI NFs-, cross-linked PANI-, and Pt-based CEs, respectively. The low fabrication cost as well as the improved light absorption highlights the potential application of the coral-like TiO2 and PANI NFs-based films in fabrication of bifacial DSSCs.
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•A new bifacial DSSC was fabricated and characterized.•Coal-like TiO2 nanostructures were synthesized through the sol–gel process.•Polyaniline nanofibers were prepared by a facile in situ polymerization.•PANI NFs-based films and coal-like TiO2 nanostructures were used as electrodes.•The fabricated DSSC showed efficiency of 8.22% due to both side irradiations.
An alternative polarization phase-shifting technique is proposed to determine the thickness of transparent thin-films. In this study, the cyclic interferometric configuration is chosen to maintain ...the stability of the operation against external vibrations. The incident light is simply split by a non-polarizing beam splitter cube to generate test and reference beams, which are subsequently polarized by a polarizing beam splitter. Both linearly polarized beams are orthogonal and counter-propagating within the interferometer. A wave plate is inserted into the common paths to introduce an intrinsic phase difference between the orthogonal polarized beams. A transparent thin-film sample, placed in one of the beam tracks, modifies the output signal in terms of the phase retardation in comparison with the reference beam. The proposed phase-shifting technique uses a moving mirror with a set of “fixed” polarizing elements, namely, a quarter-wave retarder and a polarizer, to facilitate phase extraction without rotating any polarizing devices. The measured thicknesses are compared with the measurements of the same films acquired using standard equipment such as the field-emission scanning electron microscope and spectroscopic ellipsometer. Experimental results with the corresponding measured values are in good agreement with commercial measurements. The system can be reliably utilized for non-destructive thickness measurements of transparent thin-films.
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