Transparent Conductive Films Research Articles

Facile filter cloth brush-coating of large-area uniform silver nanowire conductive films for paper-based heater

Filter cloth brush-coating (FCBC), using soft filter cloth as a brush-coating medium, in conjunction with viscous silver nanowire (AgNW) conductive solution, is used to prepare AgNW conductive films. The density and uniformity of AgNWs deposited on the substrate are controlled by the interplay between the filter cloth aperture, the conductive solution viscosity, and the brush-coating speed. Further, with appropriate AgNW concentration and flow rate, uniform AgNW transparent conductive film with sheet resistance of 18 Ω sq−1 and transmittance of 94% at 550 nm is acquired by FCBC. Due to the precise control of the coating process in FCBC, large-area uniform AgNW conductive film fabricated on printing paper has a low non-uniformity factor of 1.2% at a sheet resistance of 19.0 Ω sq−1. The resultant paper-based AgNW film heater shows sensitive and stable heating performance. FCBC shows great potential in producing large-area uniform AgNW films on various substrates.

The Real-Time Monitoring of the Laser-Induced Functionalization of Transparent Conductive Oxide Films.

Laser-induced functionalization using excimer laser irradiation has been widely applied to transparent conductive oxide films. However, exploring suitable irradiation conditions is time-consuming and cost-ineffective as there are numerous routine film fabrication and analytical processes. Thus, we herein explored a real-time monitoring technique of the laser-induced functionalization of transparent conductive oxide films. We developed two types of monitoring apparatus, electrical and optical, and applied them to magnetron-sputtered, Sn-doped In2O3 films grown on glass substrates and hydrogen-doped In2O3 films on glass or plastic substrates using a picosecond Nd:YAG pulsed laser. Both techniques could monitor the functionalization from a change in the properties of the films on glass substrates via laser irradiation, but electrical measurement was unsuitable for the plastic samples because of a laser-induced degradation of the underlying plastic substrate, which harmed proper electrical contact. Instead, we proposed that the optical properties in the near-infrared region are more suitable for monitoring. The changes in the optical properties were successfully detected visually in real-time by using an InGaAs near-infrared camera.

Thermal Scanning-Probe Lithography for Broad-Band On-Demand Plasmonic Nanostructures on Transparent Substrates.

Thermal scanning-probe lithography (t-SPL) is a high-resolution nanolithography technique that enables the nanopatterning of thermosensitive materials by means of a heated silicon tip. It does not require alignment markers and gives the possibility to assess the morphology of the sample in a noninvasive way before, during, and after the patterning. In order to exploit t-SPL at its peak performances, the writing process requires applying an electric bias between the scanning hot tip and the sample, thereby restricting its application to conductive, optically opaque, substrates. In this work, we show a t-SPL-based method, enabling the noninvasive high-resolution nanolithography of photonic nanostructures onto optically transparent substrates across a broad-band visible and near-infrared spectral range. This was possible by intercalating an ultrathin transparent conductive oxide film between the dielectric substrate and the sacrificial patterning layer. This way, nanolithography performances comparable with those typically observed on conventional semiconductor substrates are achieved without significant changes of the optical response of the final sample. We validated this innovative nanolithography approach by engineering periodic arrays of plasmonic nanoantennas and showing the capability to tune their plasmonic response over a broad-band visible and near-infrared spectral range. The optical properties of the obtained systems make them promising candidates for the fabrication of hybrid plasmonic metasurfaces supported onto fragile low-dimensional materials, thus enabling a variety of applications in nanophotonics, sensing, and thermoplasmonics.

Physical and Electrical Properties of Spray Coating Graphene Films: The Effect of Solution Concentration

Graphene nanofilms were deposited by the spray coating method at different concentrations (0.05, 0.1, 0.2, 0.3, 0.4, and 0.5 g) and prepared at 120°C. The prepared nanofilms were characterized in terms of their structural, morphological, optical, and electrical properties. The results confirm the formation of high-purity and high-crystallinity graphene nanofilms with a layered nanosheet morphology. The X-ray diffraction pattern shows the presence of pure graphene with (002) crystal planes. SEM Images show that the intended graphene films are symmetrical with few wrinkles on their surface. The graphene films show semi-transparent behavior with a maximum transmission of 50%. Raman spectroscopy shows that the relative intensity, position, and shape of the G and 2D Raman peaks change with the number of graphene layers. The electrical conductivity increases with temperature, and the conductivity can be further increased depending on the metal or metal oxide functionalization. The electrical conductivity of the graphene film deposited at a concentration of 0.3 g was significantly higher than the values reported for other concentrations. The results of this study suggest that the physical and electrical properties of spray-coated graphene films can be optimized by controlling the solution concentration, which could have potential applications in transparent conductive films.

Optical, Electrical and Structural Properties of ITO/IZO and IZO/ITO Multilayer Transparent Conductive Oxide Films Deposited via Radiofrequency Magnetron Sputtering

In this study, we investigated the potential of multilayer TCO structures, specifically those made up of Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO), for crystalline silicon heterojunction solar cells (SHJ). We used the radiofrequency (RF) magnetron sputtering method to deposit various thin-film structures under various deposition temperatures and evaluated their electrical, optical, and morphological properties. The objective was to obtain films with lower sheet resistances and higher transmittances than those of single-layer thin films. Our results show that the ITO/IZO/ITO/IZO/ITO multilayer film structure deposited at 200 °C achieves the best sheet resistance of 18.5 Ohm/sq and a high optical transmittance of over 90% at a 550 nm wavelength. This indicates that multilayer TCO structures have the potential to be more optically and electrically efficient, and that they can improve the performance of optoelectronic devices. Finally, a power conversion efficiency of 17.46% was obtained for a silicon heterojunction (SHJ) solar cell fabricated using an ITO/IZO/ITO/IZO/ITO multilayer film structure deposited at 200 °C as a front TCO. Our study provides valuable insights into the field of TCOs and offers a promising avenue for future research.

The effects of RF power on the optical and electrical properties of transparent conductive Hf-doped In2O3 thin films

Highly transparent conductivity Hf-doped In2O3 (IHFO) films were prepared by RF sputtering on the glass substrate. The effects of sputtering power on the properties of transparent conductive films were studied to optimize the sputtering conditions. X-ray photoelectronic spectra (XPS) showed that the area ratio of OⅠ (oxygen vacancies) to OⅡ (lattice oxygen) achieved the highest value (0.71) at 75 W, resulting in IHFO having the lowest resistivity (2.76 × 10−4 Ω cm). However, the film prepared at 75 W has a low transmittance originating from the intense reflection caused by the high carrier concentration. In comparison, IHFO film deposited at 65 W has a lower resistivity and higher transmittance. Therefore, the IHFO film at 65 W exhibits the maximum figure of merit (FOM) value (7.04 × 10−2 Ω−1) with a low sheet resistance (4.03 Ω/sq) and a favorable average transmittance (88.16%). The p-CuI/n-IHFO diode is exhibited with high transmittance (84.25%) in the visible region and low guiding voltage (0.89 V), implying that IHFO films can be favorably used in the optoelectronic field.

Synergism of Cl− and Br− on the controllable synthesis of flexible silver nanowires

Silver nanowires (AgNWs) exhibit excellent electrical conductivity and hold significant potential for usage in flexible electronics. AgNs can possess a suitable aspect ratio, uniformity, and flexibility that are essential for achieving high-performance flexible transparent conductive films. However, the synthesis of AgNWs presents a challenge in controlling its morphology, often resulting in varying lengths and aspect ratios that are difficult to regulate. Thus, the controlled preparation of AgNWs holds great significance. Herein, AgNWs were synthesized via a polyol method with FeCl3 and KBr composite metal salt as control agents, silver nitrate as a silver source, ethylene glycol as a reducing agent and solvent, and polyvinylpyrrolidone (PVP) as a growth director. By adjusting the ratio and dosage of FeCl3 and KBr, the morphology controllability of AgNWs was realized, and the obtained AgNWs can be straight or bendable. The surface morphology and microstructure of the AgNWs were analyzed by scanning electron microscopy (SEM). Due to the synergistic effect of FeCl3 and KBr, flexible AgNWs with an average diameter of 25–35 nm, an average length of 35–45 um, and an aspect ratio of over 1000 can be obtained. Mechanism studies have shown that through electrostatic interactions, AgCl, AgBr, NO3−, and PVP in the reaction mixture can form binding sites for AgCl-PVP-NO3− and AgBr-PVP-NO3−, thus causing the silver nanowires to become flexible. Meanwhile, the strong polarization effect caused by Br− in the reaction causes the chain growth to become subject to the dual effects of electrostatic repulsion and external forces, resulting in the formation of flexible and soft silver nanowires.

Influence of Deposition Parameters of ITO Films on the Performance of HJT Solar Cells

TCO (transparent conductive oxide) films are widely used in solar cells due to the characteristics of transparency and conductivity. In this paper, ITO (indium tin oxide) transparent conductive films are prepared on common slides by DC magnetron sputtering, and the preparation process and characteristics of ITO films are studied. The target for sputtering is ITO, with the mass ratio of In203 and Sn02 was 90% : 10%. The sheet resistance, carrier concentration, and carrier mobility of ITO films are measured and analyzed by a UV-Vis spectrophotometer, four-point probe, and Hall effect measurement system. By changing the oxygen content, deposition temperature, and sputtering power to studied the effects on the light transmittance and electrical conductivity of the ITO films, further studied the effects on the HJT (heterojunction with intrinsic thin film) solar cells, and finally determined the appropriate preparation parameters. Results show that the resistance is 6 . 4 ∗ 10 − 4 Ω • cm , the light transmittance is beyond 90.6%, efficiency is 23.78%, and bifacial ratio is 84% when oxygen content is 2.2%, sputtering power is 3 kw, and deposition temperature is 190°C.

Fast, facile and thermal damage free nanowelding of Ag nanowire for flexible transparent conductive film by pressure-assisted microwave irradiation

A fast and straightforward fabrication process for producing a robust, flexible, and transparent conductive film was demonstrated using nanowelding of Ag nanowires through pressure-assisted microwave irradiation. This innovative process effectively reduces the sheet resistance of the Ag nanowire transparent conductive film without causing any thermal distortion to the PET substrate. The microwave irradiation induces nanowelding between Ag nanowires, leading to a decrease in sheet resistance by forming nanowelding junctions. This selective heating of Ag nanowires further enhances the reduction in sheet resistance. Additionally, the application of pressure-assisted microwave irradiation allows the Ag nanowires to be embedded into the PET substrate, resulting in the formation of a robust film capable of withstanding cycling bending stress. The pressure-assisted microwave irradiation process proves to be a strong fabrication method for creating Ag nanowire transparent conductive films, especially when dealing with thermally weak substrate materials.

Microstructure analysis of graphene oxide synthesized from corn cobs waste

Graphene oxide is one carbon-based material decorated by oxygen functional group that has been applied in various field. Active oxygen functional group allows graphene oxide served as precursor for many applications including DSSC, Field Effect Transistor, LED, and Transparent Conductive Film. Unfortunately, high cost of pure raw material inhibits the wide application of graphene oxide. Corn cobs is one of highly produced waste from agricultural activity that become an unsolved environmental problem. Meanwhile, high content of carbon material in corn cob allows it to be a potential carbon source for graphene oxide synthesis. In this report the synthesis of graphene oxide from corn cobs using modified hummers method is discussed. As synthesized sample was analysed using FTIR, XRD, and SEM to confirm the successful of graphene oxide form corn cobs.

Effect of preparation conditions on the properties of nano ZnO powders during ultrasonic assisted direct precipitation process.

Transparent conductive thin films (TCO) are widely used for their excellent photoelectric properties. To prepare high-quality ZnO targets, starting with the original ZnO powder is necessary. This paper aims to explore the basic technology and method of ultrasonic-assisted direct precipitation for mass production of ZnO powder and to analyze the effects of factors such as precipitating agent, surfactant, calcination temperature, and solvent on the powder's morphology, particle size, and crystallinity. The study found that the type and amount of precipitants and surfactants affect the powder's morphology and dispersibility, while calcination temperature mainly affects the powder's morphology and crystallinity. The ethanol content in the solvent mainly affects the grain size. After testing different variables, the optimal conditions for preparing spherical ZnO powder were found to be using (NH4)2·CO3 as the precipitant, adding 3% wt of PEG-400 and 3% wt of TEA at a calcination temperature of 320°C and a 60% ethanol solvent. This resulted in a smooth surface, uniform particle size distribution, good dispersibility, high crystallinity, and particle sizes between 26-32nm.

Flexible Transparent Conductive Films of Ag/Cr2O3 Core–Shell Nanowires as Electrodes for Electroluminescent Devices and Heaters

Flexible Transparent Conductive Films of Ag/Cr₂O₃ Core–Shell Nanowires as Electrodes for Electroluminescent Devices and Heaters

Transparent conductive film of silver nanowires employed for SERS detection of mercury ions

Silver nanowires (Ag NWs)/glass transparent conductive film was prepared by one-step spin coating method. l-Cysteine (L-Cys) functionalized Ag NWs were employed for the surface-enhanced Raman scattering (SERS) detection, which was used to evaluate the photoelectric performance by detecting heavy metal Hg2+ ions. The L-Cys functionalized Ag NWs/glass transparent conductive film exhibits selective, rapid and sensitive detection to Hg2+. The limit of Hg2+ detection reaches 10−9 M, which is ten times lower than the maximum Hg2+ concentration in drinking water set by the US Environmental Protection Agency. Furthermore, this dual-function of transparent conductive silver sensor has high accuracy, and reliability, which provides new insights into the design of rapid and sensitive SERS detection of mercury ions, and indicates a great potential for efficient heavy metal detection.

Evaluation of transmission characteristics of CVD-grown graphene and effect of tuning electrical properties of graphene up to 50 GHz

Graphene has been investigated as a transparent conductive film for use in a variety of devices, and in recent years it has shown promise for use in millimeter-wave devices as 5G technology. In this study, we applied single-layer (SL), triple-layer (3L), and P-type doped 3L graphene to coplanar waveguide (CPW) transmission lines and obtained transmission characteristics (S21) from 1 to 50 GHz, which covered the 5G band. Furthermore, an equivalent circuit model of the CPW used in the measurements was constructed and simulations were performed, which showed good agreement with the measured results. The results validated the transmission properties of the graphene and the contact impedance at the interface between electrodes and the graphene in CPW circuits, which are necessary parameters for designing antennas using graphene. In addition, by comparing the transmission loss of three types of graphene, the parameters for improving the transmission characteristics were clarified.

Analysis of the Effect of Technological Parameters on the Properties of Transparent Conductive Oxides

It is shown that a promising method for obtaining transparent conductive oxides is spray pyrolysis, which allows to obtain films of proper quality without the use of vacuum. For the effective use of the spray pyrolysis method in order to obtain reproducible films with specified properties, it is necessary to take into account a variety of heterogeneous technological parameters that affect the quality of transparent conductive coatings. To this end, the authors have developed a model in the form of an oriented graph that displays the relationship of technological modes and quality parameters of transparent conductive coatings. The model displays parameters in the form of graph vertices, which are divided into technological and parameters characterizing the quality of transparent conductive coatings. The arcs connecting the vertices represent the properties of the coatings, and the arrows of the arcs indicate the direction from the action property to the reaction property. This model made it possible to systematize the influencing factors and offer an analytical description of the influencing parameters, reactions to them and properties of the synthesized coatings in the form of a system of differential equations. Based on the specified mathematical model of the relationship between technological modes and coating properties, a method for selecting optimal technological parameters has been developed in order to obtain transparent conductive coatings with specified properties. The technique has been tested on the example of the synthesis of a transparent conductive film of tin dioxide doped with antimony. Analysis of the factors affecting the surface resistance of coatings showed that the concentration of charge carriers significantly depends on the volume and concentration of impurities. The results of the analysis of experimental studies of the dependences of the concentration of charge carriers on the concentration of the impurity, the volume of the solution, on the thickness, the dependence of the surface resistance of the film on the thickness are presented

Progress in the Synthesis and Application of Transparent Conducting Film of AZO (ZnO:Al).

Due to the excellent performance and low cost of the new aluminum-doped zinc oxide (AZO) film, it is expected to replace the mature indium-doped tin oxide (ITO) film. The research status and progress of AZO transparent conductive films are summarized in this review. Moreover, the structure, optoelectronic properties, and conductive mechanism of AZO thin films are also detailed. The thin films' main preparation processes and the advantages and disadvantages of each process method are mainly discussed, and their application fields are expounded. AZO thin films with multicomponent composite structures are one of the promising development directions in transparent conductive oxide (TCO) thin films. The development of various preparation processes has promoted the production and application of thin films on a broad scale. Finally, some improvement schemes have been proposed to improve the comprehensive performance of the film. The industrialization prospects of the AZO film, as well as its great development potential in the digital world, are discussed.

Effects of dielectric layer on ductility for dielectric/Au/dielectric multilayers on polycarbonate substrate

The ductility of transparent conductive films on polycarbonate (PC) substrate is of great concern as it significantly affects the stability and longevity of aeronautic equipment. Three types of dielectric/Au/dielectric multilayers, including ITO/Au/ITO (IAI), IZO/Au/IZO (ZAZ) and AZO/Au/AZO (AAA) were fabricated to obtain highly ductile films on thick rigid PC substrate. The ductility of multilayers was comparatively investigated using in situ scanning electron microscopy test and in situ electrical resistance test under uniaxial tension. The effect of dielectric layer on ductility was elucidated according to the results of film stress and elastic modulus, and analyzed using the energy release rate approach based on the mechanics model. The results of in situ tests revealed that the crack initiation strain by morphology and the conductive failure strain of AAA were found to be 1.04 ± 0.04% and 1.47 ± 0.07%, which were superior to those of IAI and ZAZ. This result can be attributed to differences in layer stress state and layer-substrate mechanical contrast induced by different dielectric layers. Although AAA has the lower fracture toughness, the higher compressive residual stress and the smaller elastic mismatch give AAA the smallest crack driving force under the same conditions, resulting in excellent ductility.

Ultrathin Ag@ZnO Core–Shell Nanowires for Stable Flexible Transparent Conductive Films

Ultrathin Ag@ZnO Core–Shell Nanowires for Stable Flexible Transparent Conductive Films

Novel facile synthesis and room-temperature sintering of copper nanowires for solution-processed transparent conductive films

Copper nanowires (Cu NWs) are considered as the potential alternative material for indium tin oxide (ITO) which is widely used in various photoelectric devices. However, the effective and full solution-processed technology for Cu NWs transparent conductive films (TCFs) with excellent performance is lacking. Here, a facile “heterogeneous-self reduction” approach was proposed for Cu NWs synthesis with the yield as high as 62.2% using nether reductant nor crystal seed. Copper glycine heated with hexadecyltrimethylammonium chloride and oleylamine, decomposed continuously to release Cu atoms, which were nucleated and grown anisotropically into Cu NWs with aspect ratio > 1000. The “pickling-chemical sintering” solution-process was applied to form the Cu NWs TCFs using the synthesized Cu NWs. Oleylamine on the surface of purified Cu NWs was removed by pickling with acetic acid solution. After coating on PET film, the surface oxide of Cu NWs could be reduced to Cu (0) by NaBH4 solution, and the sintering of Cu NWs can be realized simultaneously. The Cu NWs TCF with a sheet resistance of 34.7 Ω sq–1 at a transmittance of 91.1% exhibits the excellent performance in capacitive sensing. This work is expected to promote the full-solution preparing of Cu NWs TCFs.

Tetrabutylammonium Tribromide-Induced Synthesis of Silver Nanowires with Ultrahigh Aspect Ratio for a Flexible Transparent Film.

Silver nanowires (AgNWs) have gained significant attention from researchers as a promising material for producing flexible transparent conductive films, which can be utilized in touch and display screens. Thereinto, the ultrahigh aspect ratio AgNW network can theoretically decrease the contact resistance effectively while still retaining considerable mechanical and optical properties. However, fabrication of high-quality AgNWs with a fine diameter and high aspect ratio is still challenging. Herein, a simple and robust approach to synthesize ultrahigh aspect ratio AgNWs is presented. This study successfully fabricated AgNWs with the highest aspect ratio up to ∼4000 and an average length of ∼72 μm by utilizing tetrabutylammonium tribromide as an auxiliary additive. The manifestation of tetrabutylammonium tribromide was proven to be beneficial for the generation of silver seeds and the expansion of AgNWs. The obtained AgNWs were utilized to create a transparent conductive film that showed low sheet resistance of 22.4 Ω/sq and high transmittance and low haze of 87.71 and 4.15%, respectively. The transmittance and haze of the vacant poly(ethylene terephthalate) support were 90.13 and 2.05%, thereby offering great potential for application in flexible transparent electrodes.