Nanowire Transparent Conductive Films Research Articles

Preparation and Optoelectrical Property of Silver Nanowire Transparent Conductive Film via Slot Die Coating

Silver nanowire transparent conductive films (AgNW TCFs), as the novel transparent electrode materials replacing ITO, are anticipated to be applied in numerous optoelectronic devices, and slot-die coating is currently acknowledged as the most suitable method for the mass production of large-sized AgNW TCFs. In this study, sodium carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA), as film-forming aids, and AgNWs, as conductive materials, were utilized to prepare a specialized AgNW ink, and a slot-die coating is employed to print and prepare AgNW TCFs. The optoelectrical properties of AgNW TCFs are optimized by adjusting the compositions of AgNW ink and the process parameters of slot-die coating. The suitable compositions of AgNW ink and the optimal parameters of slot-die coating are a CMC type of V, a PVA volume of 1 mL, a AgNW volume of 1.5 mL, a volume ratio of 30 and 45 nm AgNWs (2:1), and a coating height of 400 μm. The resultant AgNW TCFs achieve excellent comprehensive optoelectronic performance, with a sheet resistance of less than 50 Ω/sq, a visible light transmittance exceeding 92%, and a haze below 1.8%. This research provides a valuable approach to producing AgNW TCFs on a large scale via the slot-die coating.

Corrosion and conductivity damage of AgNW transparent conductive thin films under a simulated sulfur-containing atmosphere and mechanical force

Silver nanowire (AgNW) transparent conductive thin films possess high flexibility, high conductivity, high light transmittance and etc., demonstrating significant advantages in flexible electronics applications. However, in the service occasions, the coupled effect of corrosion and mechanical force easily makes the electrical conductivity of AgNW films deteriorate or even fail, which seriously affects the service reliability of AgNW films. In this work, scanning vibrating electrode technique was firstly used to confirm the existence of electrochemical corrosion on AgNW films. Furthermore, electrochemical measurements (including OCP, PDP and EIS) were carried out for researching the electrochemical corrosion process on AgNW films under different environmental factors and mechanical forces. Their surface morphologies and electrical conductivity were characterized and evaluated by the Scanning Electron Microscopy and square resistance tester respectively. Experimental results indicate that the corrosion-mechanics interaction effect aggravates the damage process of electrical conductivity of AgNW films.

Cohesively improved conductivity, transparency, and stability of Ag NW flexible transparent conductive thin films by covering Al2O3 layer

Developing feasible Ag nanowire (NW) transparent conductive thin films (TCFs) with good conductivity, transparency, mechanical durability, strong adhesion, and high stability is a great challenge. Herein, novel TCFs composed of Ag NWs/Al2O3 on polyethylene terephthalate (PET) substrates with synchronously improved conductivity, transparency, mechanical durability, adhesion, and stability, are prepared. The corresponding values (before coating Al2O3: 13.0 Ω/sq. at 86.1 %, after coating Al2O3: 11.7 Ω/sq. at 87.7 %) indicate that the deposition of Al2O3 enhances the transparency and conductivity of Ag NW networks. Moreover, the resistance does not change significantly after 50 taping cycles and 2000 bending cycles with a bending radius of 5.0 mm, indicating the strong adhesion and good mechanical flexibility of Al2O3/Ag NWs composites. In addition, Al2O3/Ag NWs composites possess excellent stability to resist strong oxidizing, hot and humid environments. As a proof of concept, the flexible transparent heater prepared by Al2O3/Ag NWs composites is successfully demonstrated, verifying the practicability.

The preparation of shear coating for silver nanowire transparent conductive films and its electrical performance anisotropy

The preparation of shear coating for silver nanowire transparent conductive films and its electrical performance anisotropy

A two-step junction welding technique for achieving high-performance broadband silver nanowire transparent conductive films.

Transparent conductive films (TCFs) are critical components of various optoelectronic and photovoltaic devices. The performance of TCFs is mainly ascribed to their superior transparency and low sheet resistance. However, the welding strategy for silver nanowires (AgNWs), the primary material used in TCFs, can significantly affect the optical and electrical properties of the films. Herein, we report a simple and effective method for preparing AgNWs TCFs with superior broadband transparency and conductivity. By applying pressure to the surface of graphene, we successfully enhanced the tight connections between loose nanowires. Based on this, we developed a high-performance, wide-spectrum TCF and employed ultraviolet welding as its post-treatment method. The sheet resistance of the electrode decreased to 27.1 Ω sq-1 with the addition of graphene films, and subsequent UV light welding further reduced the resistance value by 25.1%. Moreover, the incorporation of graphene films provides excellent protection for AgNWs against oxidation. One month later, compared to AgNWs without a protective coating, the increase in sheet resistance was reduced by 414.6%. This study provides a new method for preparing TCFs with wide spectrum and high performance.

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.

Surface modification of silver nanowire transparent conductive films by metal oxide nanoparticles and the application of electric ceramic teacup

Surface modification of silver nanowire transparent conductive films by metal oxide nanoparticles and the application of electric ceramic teacup

Shear force strategy for preparation of aligned silver nanowire transparent conductive thin films

Silver nanowires transparent conductive films (AgNWs-TCFs) prepared by traditional rotary coating method, which will cause the failure of conductive channels of AgNWs-TCFs under current load because of their AgNWs distributing randomly, were restricted its industrial application of flexible electronic devices. In this paper, the aligned AgNWs-TCFs were deposited by using the shear force from the high-speed rotating concentrated nanowire solution. Based on the rheological performance test results, the preparation conditions were set at nanowire solution of 2.0 mg/mL and the substrate immersed in PEI of 0.5 mg/mL for 10 min. The aligned AgNWs-TCFs with one-layer structure (1 L-Aligned AgNWs-TCFs) and with perpendicular two-layer structure (2 L-Aligned AgNWs-TCFs) were obtained by shear rate of 400 rpm. It was found that the resistance of 1 L-Aligned AgNWs-TCFs showed a high degree of anisotropy, with a ratio of longitudinal and lateral resistance values of 3.60, while the resistance of 2 L-Aligned AgNWs-TCFs is isotropic similarly to randomly distribution AgNWs-TCFs. However, the current-loading stability of 2 L-Aligned AgNWs-TCFs is significantly improved. The failure voltage of 2 L-Aligned AgNWs-TCFs is 13 V, but that of randomly distributed AgNWs-TCFs is only 9 V. Compared to other aligned AgNWs-TCFs preparation methods, our method enables controllable preparation and industrial development of aligned AgNWs-TCFs.

Improvement of Electrical Properties of Silver Nanowires Transparent Conductive by Metal Oxide Nanoparticles Modification

At present, silver nanowire transparent conductive films (AgNWs-TCFs) still have problems such as high resistance of AgNWs network nodes, uneven distribution of resistance and poor electrical performance stability, which restrict their commercial application. Different from chemical modification, in this paper, a method of modifying AgNWs-TCFs with metal oxide nanoparticles (MONPs) is proposed, that is, ZnO, SnO2, Al2O3 and TiO2 etc., four transparent metal oxides are used as targets respectively in a magnetron sputtering process, modifying the silver nanowire network wire–wire junctions and silver nanowire in AgNWs-TCFs using active MONPs generated by magnetron sputtering. A series of AgNWs@MONPs for the AgNWs@ZnO-TCFs, AgNWs@SnO2-TCFs, AgNWs@Al2O3-TCFs and AgNWs@TiO2-TCFs were obtained. A significant decrease in the resistance of AgNWs-TCFs through the modification of MONPs was shown. Respectively, the reduction of resistance was 75.6%, 70.4%, 53.2% and 59.8% for AgNWs@ZnO-TCFs, AgNWs@SnO2-TCFs, AgNWs@Al2O3-TCFs and AgNWs@TiO2-TCFs. Correspondingly, its non-uniformity of resistance distribution was 12.5% (18.2% before), 10.0% (17.1% before), 10.1% (24.3% before) and 10.6% (13.4% before), respectively, which markedly improved the uniformity of electrical property. Respectively, their failure voltages reach 16, 16, 15 and 16 (V), so accordingly, the electrical stability is considerably enhanced. In addition, the uniformity of temperature distribution was also significantly optimized with its temperature non-uniformity of 10.4%, 8.7%, 10.3% and 9.6%, respectively. Contrast that with AgNWs@MONPs, and the failure voltages and temperature non-uniformity of AgNWs-TCFs are 12 V and 40.6%.

UV–Vis Transparent Conductive Film Based on Cross-Linked Ag Nanowire Network: A Design for Photoelectrochemical Device

The FTO/ITO transparent conductive films currently used in photoelectrochemical devices limit performance improvement due to their low conductivity, poor flexibility, and inability to transmit UV light. Ag nanowire-based films are a very promising alternative to address these problems, and are considered to be the next generation in transparent conductive film. Here, we prepared a cross-linked nano-network composed of ultra-long Ag nanowires by a special physical template method. The obtained Ag nanowire transparent conductive film has a transmittance of over 80% in a wide range of 200 nm–900 nm, a sheet resistance as small as 5.2 Ω/sq, and can be easily transferred to various substrates without damage. These results have obvious advantages over Ag nanowire films obtained by traditional chemical methods. Considering the special requirements of photoelectrochemical devices, we have multifunctionally enhanced the film by a TiO2 layer. The heat-resistant temperature of transparent conductive film was increased from 375 °C to 485 °C, and the mechanical stability was also significantly improved. The presence of the multifunctional layer is expected to suppress the carrier recombination in self-powered photoelectrochemical devices and improve the electron diffusion in the longitudinal direction of the electrode, while serving as a seed layer to grow active materials. The high-quality Ag nanowire network and functional layer synergize to obtain a UV–Visible transparent conductive film with good light transmittance, conductivity, and stability. We believe that it can play an important role in improving the performance of photoelectrochemical devices, especially the UV devices.

Facile fabrication of large-scale silver nanowire transparent conductive films by screen printing

Silver nanowire transparent conductive films (AgNW TCFs) were facilely prepared by screen printing conductive ink on a polyethylene terephthalate (PET) substrate, and the effects of ink compositions and oily stencil on the optoelectrical properties of AgNW TCFs were investigated in detail. 7.3 mg·ml−1 hydroxypropyl methylcellulose (HPMC), 4.12 mg·ml−1 AgNWs and 98T oily stencil allow the preparation of large-scale AgNW TCFs with high transmittance, low square resistance and high uniformity. The resultant screen printed AgNW TCFs possesses a sheet resistance as low as 13.0 ± 0.6 Ω sq−1, a transmittance of about 95.3% at 550 nm wavelength (deducting the background) and a haze of 3.86 (deducting the background), and can achieve a surface root mean square roughness of 3.33 nm, a film size of 15 × 20 cm2 and personalized pattern by means of the screen printing process. The transparent film heater (TFH) constructed by AgNW TCFs can rise to a usable temperature of 55 °C at a low voltage of 4 V within 80 s. This process provides a simple strategy for fabricating uniform, patterned and large size AgNW TCFs for various devices.

Post‐Treatment of Screen‐Printed Silver Nanowire Networks for Highly Conductive Flexible Transparent Films

AbstractScreen printing is an important technique for creating 2D conductive patterns with high conductivity and resolution. Non‐conductive additives are thus required in printable ink formulation in order to achieve appropriate viscosity and rheological behaviors. However, it is still a challenge to recover the conductivity of the printed networks after screen printing, while keeping the integrity of the patterns during repeated water‐washing. Herein, a series of post‐treatments are introduced into the washing process in order to achieve high‐quality silver nanowire (Ag NW) transparent conductive films. Screen‐printed patterns can be well maintained because of the enhanced adhesion between the Ag NW networks and flexible poly(ethylene terephthalate) substrates. High‐performance transparent conductive film with extremely low sheet resistance (0.72 Ω sq−1) is achieved by combining plasma treatment, thermal annealing, and high pressure, making screen‐printed Ag NW conductive networks promising to be used in the next‐generation flexible optoelectronic devices.

Moisture-Assisted Formation of High-Quality Silver Nanowire Transparent Conductive Films with Low Junction Resistance

Silver nanowire (AgNWs) transparent conductive film (TCF) is considered to be the most favorable material to replace indium tin oxide (ITO) as the next-generation transparent conductive film. However, the disadvantages of AgNWs, such as easy oxidation and high wire-wire junction resistance, dramatically limit its commercial application. In this paper, moisture treatment was adopted, and water was dripped on the surface of AgNWs film or breathed on the surface so that the surface was covered with a layer of water vapor. The morphology of silver nanowire mesh nodes is complex, and the curvature is large. According to the capillary condensation theory, water molecules preferentially condense near the geometric surface with significant curvature. The capillary force is generated, making the wire-wire junction of AgNWs mesh bond tightly, resulting in good ohmic contact. The experimental results show that AgNWs-TCF treated by moisture has better conductivity, with an average sheet resistance of 20 Ω/sq and more uniform electrical properties. The bending test and adhesion test showed that AgNWs-TCF treated by moisture still exhibited good mechanical bending resistance and environmental stability.

Structural manipulation of silver nanowire transparent conductive films for optoelectrical property optimization in different application fields

Silver nanowire films as a kind of bright flexible transparent conductive material are expected to have the sheet resistance as low as possible, the critically high optical transmittance and the wide range haze for different applications. Herein, we fabricated a series of silver nanowire transparent conductive films with different structural parameters and sheet resistances. By analyzing the relationship between the structural parameters and optical properties, it was found that the long and thick nanowires led to high transmittance and haze, while long and thin nanowires resulted in high transmittance and low haze. Experimental and theoretical results give instructions of designing silver nanowire films from structural manipulation for various applications in need of high haze, low haze with high transmittance or low haze with high conductivity. Through modification of the diameter, length and density of the silver nanowires, the transparent conductive films with sheet resistance below 75 ohm/square and transmittance above 80% were achieved, while haze at the wavelength of 550 nm could be controlled between 1% and 25%. This work provides insight for practical application of silver nanowires in optoelectronic devices.

Enhanced stability of silver nanowire transparent conductive films against ultraviolet light illumination

Silver nanowires are susceptible to degradation under ultraviolet (UV) light illumination. Encapsulating silver nanowire transparent conductive films (AgNW TCFs) with UV shielding materials usually result in the increasing of the sheet resistance or the decrease of the visible light transparency. Herein, we combine a reducing species (FeSO4) and a thin layer (overcoating) of UV shielding material to solve the stability and the optical performance issues simultaneously. The AgNW TCFs show excellent stability under continuous UV light illumination for 14 h, and their sheet resistance varies only 6%. The dramatic enhancement of the stability against UV light illumination for as-obtained TCFs will make them viable for real-world applications in touch panels and displays.

Solution Process Fabrication of Silver Nanowire Composite Transparent Conductive Films with Tunable Work Function

Solution processed silver nanowire transparent conductive films (AgNW TCFs) have attracted substantial attention for various devices, and optoelectrical properties, surface roughness and work function are major issues affecting commercial applications. In this work, work function tunable AgNW-metal oxide composite TCFs (AgNW composite TCFs) were fabricated by filling AgNW networks with ZnO and Au/MoO3 thin films respectively. The introduction of nanoparticle constructed ZnO thin film as an electron transport layer decreases the work function from 3.82 eV of pristine AgNW TCFs to 2.76 eV due to the charges transport between AgNWs and ZnO nanoparticles, while the Au/MoO3 thin film as a hole injection layer increases the work function to 4.46 eV. The work function tunable AgNW composite TCFs show excellent optoelectronic properties with a sheet resistance of 17 Ω/sq and a transmittance of about 90%. Conductive metal oxides and metal nanoparticles filling the holes of AgNW networks improve the rough surface, uneven electronic field and chemical durability especially for better operating time and stability of organic optoelectrical devices, and provide a simple strategy for regulating the performance of AgNW TCFs.

An electrochemical method to rapidly assess the environmental risk of silver release from nanowire transparent conductive films

Silver nanowires (AgNW) are new nanomaterials designed to be incorporated into transparent conductive films in electronics, microelectrodes, heated surfaces and others. Although in these films, the AgNW are generally protected by a coating material, a risk for release of silver at all stages of the nanoproduct life cycle does exist due to corrodibility of the metal. Since ionic and nanoparticulate Ag represent a toxicological risk for a large number of living cells, there is a need for quantifying the potential Ag release from these product components. We developed an electrochemical method to evaluate possible corrosion activity of silver in AgNW transparent conductive films (TCFs) and concomitant Ag+ release. A polysiloxane polymer was used as protective coating of AgNW TCFs. A consistent correlation is observed between the degree of corrosion and the coatings' characteristics, in particular the thicknesses. A major advantage of the new approach, compared to classical aging studies, is the short experimentation time: 20 min are sufficient for a diagnostic result. The method is an accelerated corrosion and release test. It is environmentally sound methodology with use of very low electric power and with no harmful reagents. A particularly attractive application could be in the field of environmental risk assessment of metals from portable electronics and biosensors.

One-step aqueous fabrication of a silver nanowire composite transparent conductive film with high uniformity and stability

High-performance silver nanowire transparent conductive films composited with the chitosan–lactic acid were fabricated with an aqueous ink via a one-step solution process.

A facile method to prepare silver nanowire transparent conductive film for heaters

We presented a facile method to prepare silver nanowire (Ag NW) transparent conductive film (TCF) for heaters. Hydroxylpropyl methyl cellulose (HPMC) was used for achieving the excellent dispersity of Ag NWs owing to the hydrogen bonding interaction, at the same time, improved the adhesion between the Ag NW and the substrate. Moreover, the transmittance of the conductive film was also promoted. The as-obtained TCF exhibited an outstanding thermal stability as for heaters, which is better than the Ag NW/metal oxide and Ag NW/carbon nanotube hybrid structures. What’s more, the heaters of thermoplastic polyurethanes (TPU)/Ag NW/hydrogel sandwich structure were also fabricated, the performance indicated that the heaters can be used in heating suit and healthcare. We believed that this work can provide a facile method for the preparation of TCF with good practicability.

Sandwich-Structured Silver Nanowire Transparent Conductive Films with 3H Hardness and Robust Flexibility for Potential Applications in Curved Touch Screens.

A sandwich-structured bottom hard-coat/silver nanowire/top hard-coat (BHC/AgNW/THC) transparent conductive film (TCF) has been prepared by embedding the functional AgNW layer between two HC layers. The BHC/AgNW/THC TCFs show high scratch resistance with a hardness of 3H due to the enhanced adhesion to the substrate. In addition, the BHC/AgNW/THC TCFs exhibit a transmittance of 90.6% and a haze of 1% at 550 nm under a sheet resistance of 72 Ω/sq. Furthermore, highly enhanced long-term stability has been guaranteed by the HC layers due to their excellent gas barrier property. The amazing fact is that hard coating has little effect on the flexibility of AgNW films especially under extreme bending conditions and negligible resistance change could be observed after bending over thousands of times. Consequently, the greatly improved performance of BHC/AgNW/THC TCFs provided by employing hard coating layers paves the way for real-world applications of flexible AgNWs in vast areas that rigid indium tin oxide is not suitable.