Search

In this work, nitrogen (N)‐doped graphene film is synthesized, as a photo‐catalyst, on one side of the copper foam by chemical vapor deposition and the copper foam is directly used as an electrode after porous Pd@rGO cathode loading to the other side of the foam for the photo‐assisted charging of the Li‐ion oxygen battery. The amount of urea (CO(NH2)2), which is used as N atom source, is optimized to get maximum photo‐anodic currents from the n‐type graphene films. The optical band gap and the valance band edge potential of the optimized N‐doped graphene film are determined as 2.00 eV and 3.71 VLi+/Li, respectively. X‐ray photoelectron spectra provided that the atomic percent of N atoms in the graphene film is 1.34% and the graphitic, pyrrolic and pyridinic N atom percentages are 54.01%, 42.20% and 3.79%, respectively. The photo‐assisted charging tests indicated that the N‐doped graphene film photo‐catalyst reduced the charging potential significantly even at 1000 mA g−1 (0.1 mA cm−2) current density and improved the cyclic discharge‐charge performance of the Li‐ion oxygen battery considerably. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) video is a special video representation with an artificial stereoscopic vision effect that increases the depth perception of the viewers. The quality of a 3D video is generally measured based on the similarity to stereoscopic vision obtained with the human vision system (HVS). The reason for the usage of these high-cost and time-consuming subjective tests is due to the lack of an objective video Quality of Experience (QoE) evaluation method that models the HVS. In this paper, we propose a hybrid 3D-video QoE evaluation method based on spatial resolution associated with depth cues (i.e., motion information, blurriness, retinal-image size, and convergence). The proposed method successfully models the HVS by considering the 3D video parameters that directly affect depth perception, which is the most important element of stereoscopic vision. Experimental results show that the measurement of the 3D-video QoE by the proposed hybrid method outperforms the widely used existing methods. It is also found that the proposed method has a high correlation with the HVS. Consequently, the results suggest that the proposed hybrid method can be conveniently utilized for the 3D-video QoE evaluation, especially in real-time applications. [ABSTRACT FROM AUTHOR]

Paratesticular fibrous pseudotumors (PFPs) are rare pathologies with quite wide and variable topographic-morphological features. It is difficult to distinguish PFPs from malignant masses. Treatment can be done by resection of the mass. We reported a young patient’s findings about this rare pathology.

In this study, we aimed to state the relationship between testis, epididymis and vas deference, in adult cases with nonpalpable testis. Between January 1996 and December 2009, we evaluated 154 adult cases with nonpalpable testes. Mean age was 23 years (20-27 years). Explorations were performed by open inguinal incision, laparoscopy, and by inguinal incision and laparoscopy together on 22, 131 and 1 patient, respectively. Of all the unilateral cases, 32 were accepted as vanishing testis. In five of these cases, vas deference was ending inside the abdomen, and in the others, it was ending inside the scrotum. In the remaining 99 unilateral and 22 bilateral cases, 143 testes were found in total. Testes were found in the inguinal canal as atrophic in one case, at the right renal pedicle level with dysmorphic testis in one case, and anterior to the internal ring between the bladder and the common iliac vessels at a smaller than normal size in 119 cases. One (0.69%) case did not have epididymis. While epididymis was attached to the testis only at the head and tail locations in 88 (61.53%) cases, it was totally attached to the testis in 54 (37.76%) cases. There is an obviously high incidence rate of testis and vas deference anomalies, where epididymis is the most frequent one. In cases with abdominal testes, this rate is highest for high localised abdominal testes.

Effect of thin film deposition route on the morphology and performance of molybdenum oxide (MoO3) based electrochromic devices was investigated. For the deposition of thin films, a sequential deposition method, which includes ultrasonic spray pyrolysis (USP) and thermal evaporation methods was used. Films deposited solely using either USP or thermal evaporation method were used as control samples. Following deposition, MoO3 thin films were then characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy and atomic force microscopy. Surface characteristics and chemical structure of the deposited thin films were found to depend extensively on the deposition route. Electrochromic performance and reversibility of the samples were evaluated using ultraviolet-visible spectrophotometer and cyclic voltammetry. Sample prepared by USP method showed low coloration efficiency (16 cm² C-1), but high stability. In contrast, sample prepared by thermal evaporation had high coloration efficiency (30 cm² C-1), but low stability. Sample prepared by sequential deposition method showed the highest coloration efficiency (33 cm² C-1) among other samples and maintained its stability with cycling. The sequential deposition route investigated in this work is highly promising and might be extended to other metal oxide systems. [ABSTRACT FROM AUTHOR]

The genotoxicity potential of silver nanowires synthesized via the solution-based polyol method has been investigated. They were found to be non-mutagenic in three Salmonella strains and were not genotoxic in a clastogenicity assay in mice. Residual surfactant was found to have an effect on the toxicological properties of the nanowires by increasing the rate of Ag+release. Residual surfactant can be easily degraded via a UV treatment. [ABSTRACT FROM AUTHOR]

Color-changing energy storage devices that can easily communicate with the user carry the potential to be integrated into smart electronics. In this work, nanocomposite electrochromic supercapacitor electrodes were fabricated with silver nanowire (Ag NW) network electrodes and a green to transmissive electrochromic polymer, PDOPEQ. High transparency and conductivity of Ag NW network current collectors allowed the fabrication of electrochromic supercapacitors and investigation of the spectroelectrochemical and electrochemical properties of the PDOPEQ. Previously reported electrochromic properties such as long term electrochromic switching stability and vibrant color change for PDOPEQ were well transferred into electrochromic capacitors. Investigated electrochromic supercapacitors changed their color from vibrant green to transparent with superior characteristics. Specific capacitance of the fabricated nanocomposite electrodes was calculated as 61.5 F g-1 at a current density of 0.1 A g-1 and to the best of our knowledge, one of the highest capacity retention value was obtained upon 20000 galvanostatic charge-discharge cycles. With these color options and electrochemical performance, investigated conducting polymer (CP) holds strong promise to be used in electrochromic supercapacitors. [ABSTRACT FROM AUTHOR]

We present a novel one-dimensional coaxial architecture composed of silver nanowire (Ag NW) network core and nickel hydroxide (Ni(OH) 2 ) shell for the realization of coaxial nanocomposite electrode materials for supercapacitors. Ag NWs are formed conductive networks via spray coating onto polyethylene terephthalate (PET) substrates and Ni(OH) 2 is gradually electrodeposited onto the Ag NW network to fabricate core-shell electrodes for supercapacitors. Synergy of highly conductive Ag NWs and high capacitive Ni(OH) 2 facilitate ion and electron transport, enhance electrochemical properties and result in a specific capacitance of 1165.2 F g −1 at a current density of 3 A g −1 . After 3000 cycles, fabricated nanocomposite electrodes show 93% capacity retention. The rational design explored in this study points out the potential of nanowire based coaxial energy storage devices. [ABSTRACT FROM AUTHOR]

We report on the fabrication and characterization of solution-processed, highly flexible, silicon nanowire network based metal-semiconductor-metal photodetectors. Both the active part of the device and the electrodes are made of nanowire networks that provide both flexibility and transparency. Fabricated photodetectors showed a fast dynamic response, 0.43 ms for the rise and 0.58 ms for the fall-time, with a decent on/off ratio of 20. The effect of nanowire-density on transmittance and light on/off behavior were both investigated. Flexible photodetectors, on the other hand, were fabricated on polyethyleneterephthalate substrates and showed similar photodetector characteristics upon bending down to a radius of 1 cm. [ABSTRACT FROM AUTHOR]

Silver nanowire (Ag NW) networks are promising candidates for replacement of indium tin oxide (ITO). However, transparent conductors based on Ag NW networks often suffer from 'haziness' resulting from surface roughness. Thus, in addition to achieving suitable transparency and conductivity, surface roughness must be minimized if realistic implementation of Ag NW networks as transparent conductors is to be realized. In this work, we have reduced the surface roughness of Ag NW networks to below 5 nm as compared to 54 nm for as-deposited Ag NWs through optimization of the low temperature annealing treatment and planarization by poly(3,4 ethylenedioxythiophene)-poly(styrenesulfanate). Using this method, we have been able to produce Ag NW networks with transmittances and sheet resistances of 87% and 11Ω=sq, respectively. These are some of the best values reported for non-oxide-based transparent conductors. Incorporation of these smooth Ag networks into polymer light emitting diodes fabricated in our laboratory yields device characteristics that are comparable to or better than those with commercially available ITO. [ABSTRACT FROM AUTHOR]

We report on the fabrication and characterization of transparent and fully solution processed, nanowire based ultraviolet (UV) photodetectors with high responsivity. For this purpose, UV sensitive zinc oxide (ZnO) nanowires were grown hydrothermally on transparent electrodes formed by spray coated network of silver (Ag) nanowires. Fabricated UV photodetectors showed short recovery time, around 4 s, with a decent on/off ratio of 2600. Effect of in-situ annealing and nanowire length was investigated. Our design provides a simple and cost effective approach for the fabrication of high performance UV photodetectors. [ABSTRACT FROM AUTHOR]

We report on the fabrication and characterization of all nanowire (NW) network photodetectors. For this purpose, germanium (Ge) NW networks are used as active semiconducting elements, whereas single walled carbon nanotube (SWNT) and silver (Ag) NW networks are used as the contacts. Following their synthesis, all NW networks are deposited through simple solution based methods. Photoresponse characteristics and transparency of the photodetectors for different Ge NW densities are measured. The fabricated devices show a large response with short relaxation times (<10 ms), are flexible and transparent within the visible spectrum. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries (ZIBs) are gaining attraction for large-scale energy storage systems due to their high safety, significant capacity, cost-effectiveness, and environmental friendliness. On the other hand, the development of aqueous ZIBs is restricted by the limited practical application of zinc (Zn) because of the high reactivity of Zn in aqueous electrolytes, which results in the severe dendrite growth and parasitic side reactions such as hydrogen evolution reaction (HER). In this study, heteroatom-doped carbon porous surface modification by laser-assisted carbonization of copper (Cu) doped polyaniline (PANI) is designed and fabricated on top of the Zn metal anode (c-Cu-PANI/Zn). The c-Cu-PANI surface-modified Zn anodes exhibit high electrochemical stability and performance during the Zn plating-stripping cycles and suppress the dendrite formation. The symmetrical cell and half-cell with the c-Cu-PANI/Zn anodes exhibit stable cycles for 6000 h and 100% Coulombic efficiency for 2500 cycles, respectively. Moreover, the c-Cu-PANI/Zn║V 2 O 5 cell delivers a high specific capacity of 319 mAh g -1 at 0.2 A g -1 , which is significantly higher than that of the bare Zn║V 2 O 5 cell (240 mAh g -1 ). It is believed that applying c-Cu-PANI as a surface modification can enhance the stability and reversibility of the Zn anodes, therefore accelerating the commercialization of ZIBs., (© 2024 Wiley‐VCH GmbH.)

In this work, nitrogen (N)-doped graphene film is synthesized, as a photo-catalyst, on one side of the copper foam by chemical vapor deposition and the copper foam is directly used as an electrode after porous Pd@rGO cathode loading to the other side of the foam for the photo-assisted charging of the Li-ion oxygen battery. The amount of urea (CO(NH 2 ) 2 ), which is used as N atom source, is optimized to get maximum photo-anodic currents from the n-type graphene films. The optical band gap and the valance band edge potential of the optimized N-doped graphene film are determined as 2.00 eV and 3.71 V Li+/Li , respectively. X-ray photoelectron spectra provided that the atomic percent of N atoms in the graphene film is 1.34% and the graphitic, pyrrolic and pyridinic N atom percentages are 54.01%, 42.20% and 3.79%, respectively. The photo-assisted charging tests indicated that the N-doped graphene film photo-catalyst reduced the charging potential significantly even at 1000 mA g -1 (0.1 mA cm -2 ) current density and improved the cyclic discharge-charge performance of the Li-ion oxygen battery considerably., Competing Interests: The authors declare no conflict of interest., (© 2023 The Authors. Global Challenges published by Wiley‐VCH GmbH.)

Using chemically synthesized silver nanowires with 5-fold twinning planes as a model system, a bottom-up process to generate a bulk nanostructured metal has been demonstrated. Although the nanowires would be shortened and deformed during densification, they are chosen as a model system because they are currently the most scalable and convenient way to obtain Ag particles with high twinning densities. Direct cold pressing of a silver nanowire filter cake did not generate a sufficiently cohesive sample, while hot pressing at 190 °C for 8 h resulted in extensive sintering, eliminating the nanowire morphology. Copper was then electroplated on the silver nanowires as a binder and filler to increase the densification upon hot pressing; despite nonuniform plating across the thickness of the filter cake, the thermal stability of the nanowires was increased, allowing hot pressing at 390 °C. Finally, a uniform copper coating on silver nanowires was achieved by electroless plating, leading to cohesive bulk metal after hot pressing.

Silver nanowire (Ag NW) networks are one of the most promising candidates for the replacement of indium tin oxide (ITO) thin films in many different applications. Recently, Ag-NW-based transparent heaters (THs) showed excellent heating performance. In order to overcome the instability issues of Ag NW networks, researchers have offered different hybrid structures. However, these approaches not only require extra processing, but also decrease the optical performance of Ag NW networks. So, it is important to investigate and determine the thermal performance limits of bare-Ag-NW-network-based THs. Herein, we report on the effect of NW density, contact geometry, applied bias, flexing and incremental bias application on the TH performance of Ag NW networks. Ag-NW-network-based THs with a sheet resistance and percentage transmittance of 4.3 Ω sq(-1) and 83.3%, respectively, and a NW density of 1.6 NW μm(-2) reached a maximum temperature of 275 °C under incremental bias application (5 V maximum). With this performance, our results provide a different perspective on bare-Ag-NW-network-based transparent heaters.

The modification of insulating fabrics with electrically conductive nanomaterials has opened up a novel application field. With the help of Joule heating mechanism, conductive fabrics can be used as mobile heaters. In this work, heatable textiles are fabricated using silver nanowires (Ag NWs). Cotton fabrics are decorated with polyol synthesized Ag NWs via a simple dip-and-dry method. The time-dependent thermal response of the fabrics under different applied voltages is investigated. It is found that the fabrics can be heated to 50 °C under an applied power density of as low as 0.05 W cm(-2). Uniform deposition of Ag NWs resulted in the homogeneous generation of heat. In addition, the stability of the fabrics with time and under different bending and washing conditions is examined. Moreover, a simple control circuit is fabricated and integrated in order to demonstrate the high potential of the fabrics for mobile applications. This work provides a roadmap for researchers who would like to work on heatable textiles with metallic NWs.

High enhancement of fluorescence emission, improved fluorophore photostability, and significant reduction of fluorescence lifetimes have been obtained from high aspect ratio (>100) silver (Ag) nanowires. These quantities are found to depend on the surface loading of Ag nanowires on glass slides, where the enhancement of fluorescence emission increases with the density of nanowires. The surface loading dependence was attributed to the creation of intense electric fields around the network of Ag nanowires and to the coupling of fluorophore excited states that takes place efficiently at a distance of 10 nm from the surface of nanowires, which was confirmed by theoretical calculations. The enhancement of fluorescence emission of fluorescein isothiocyanate (FITC) was assessed by fluorescence spectroscopy and fluorescence-lifetime imaging microscopy (FLIM) to demonstrate the potential of high aspect ratio Ag nanowires. Fluorescence enhancement factors exceeding 14 were observed on Ag nanowires with high loading by FLIM. The photostability of FITC was the highest on nanowires with medium loading under continuous laser excitation for 10 min because of the significant reduction in the fluorescence lifetime of FITC on these surfaces. These results clearly demonstrate the potential of Ag nanowires in metal-enhanced fluorescence-based applications of biosensing on planar surfaces and cellular imaging.