Transparent Conductive Films Research Articles

Ferromagnetic and photoluminescence properties of transparent conductive Cd1-xSnxO thin films for light emitting diode applications

Ferromagnetic and photoluminescence properties of transparent conductive Cd1-xSnxO thin films for light emitting diode applications

Piezoelectric dispenser printing and intense pulsed light sintering of AgNW/PEDOT:PSS hybrid transparent conductive films

A hybrid transparent conductive films (TCFs) combining silver nanowires (AgNWs) and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) was fabricated using a piezoelectric dispenser printing method. The innovation lies in optimizing the ink composition and employing intense pulsed light sintering to enhance the TCF's performance. The optimized AgNW/PEDOT:PSS mixture, with an 8:2 ratio, achieved a figure of merit (FOM) of 28.05 × 10-3Ω-1, corresponding to a sheet resistance of 9.93 Ω sq-1and a transmittance of 88.0%. This represents a significant improvement over the pre-sintering FOM of 24.09 × 10-3Ω-1. Additionally, the hybrid TCFs exhibited outstanding structural stability, maintaining functionality after 7000 mechanical bending cycles. The results enable applications in flexible optoelectronic devices, and highlight the potential of this method to produce high-performance, flexible, and durable transparent electrodes, advancing the development of next-generation optoelectronic devices.

Highly Transparent Conductive Gallium-Doped Zinc Oxide Thin Films Grown by Reactive Plasma Deposition for Silicon Heterojunction Solar Cells

Highly Transparent Conductive Gallium-Doped Zinc Oxide Thin Films Grown by Reactive Plasma Deposition for Silicon Heterojunction Solar Cells

Optoelectronic effect of Al-based buffer layers on Al-doped ZnO thin transparent conductive films on flexible substrates

AZO (Al-doped ZnO) film is a transparent conductive film that offers a simple preparation process, low cost, non-toxicity, and excellent stability. It serves as a high-quality material extensively used in liquid crystal displays, solar cells, and other fields. In this study, AZO thin films were prepared on a PET substrate with an Al2O3 buffer layer using the magnetron sputtering method. The deposition parameters were optimized through the Taguchi method and Grey Correlation Analysis. The results demonstrate that the optimal deposition parameters for achieving superior photoelectric properties during the fabrication of AZO films are 100 W (radio frequency power), 1.0 Pa (sputtering pressure), 20 min (coating time), and 20°C (substrate temperature). Furthermore, the incorporation of an Al2O3 buffer layer enhances the quality of AZO film on PET substrate. This investigation successfully deposited uniform and highly efficient AZO thin films onto flexible PET substrates at low temperatures, thereby expanding their potential applications in flexible electronics.

Effect of solutions acidity on Haacke’s Figure of Merit of ZnO and ZnO:F thin films deposited by ultrasonic spray pyrolysis

Fluorine-doped zinc oxide (ZnO:F) thin films are valued for their potential as transparent conductive materials, particularly in optoelectronic applications. In this work, the deposition of highly conductive and transparent fluorine-doped ZnO thin films, deposited by chemical spray on glass substrates is reported. The effect of acetic (AcAc) in the initial fresh solution on Haacke’s Figure of Merit (Φ) of both zinc oxide (ZnO) and fluorine-doped zinc oxide (ZnO:F) thin films was studied. The substrate temperature was fixed to 450°C, and two deposition times (8 and 14 min) were tested. Accordingly, the optical and transport properties, as well as the structural and morphological characteristics of the films were measured. The results indicate that the samples are polycrystalline in all cases and exhibit a wurtzite-type structure of ZnO. The variation of AcAc in the starting solution causes a switch in preferential growth from (002) to (001). As the AcAc content increases, the surface morphology of the films reveals the formation of well-defined hexagonal grains, and the grain size increases. Conversely, the transmittance decreases as the acetic acid increases, which can attributed to carbon incorporation into the film. In addition, the band gap values of the films varied from 3.2 to 3.4 eV. Also, as the acetic acid concentration increased, a drop in the electrical resistivity of ZnO thin films on the order of 0.016 Ω⋅ cm was found for the ZnO:F films deposited with fresh solution for 14 min. This can be ascribed to a dense acetic cloud formed during the synthesis process, trapping volatile F species that incorporate into the ZnO lattice. This enhances Haacke’s Figure of Merit of ZnO:F films deposited with a fresh solution, demonstrating their potential use for application as transparent conductive films. This contrasts with other synthesis methods that require longer aging time in the precursor solution, making these findings useful for large-scale and more efficient production of transparent conductive films.

The Impact of Substrate Temperature on the Adhesion Strength of Electroplated Copper on an Al-Doped ZnO/Si System.

This research, which involved a comprehensive methodology, including depositing electroplated copper on a copper seed layer and Al-doped ZnO (AZO) thin films on textured silicon substrates using DC magnetron sputtering with varying substrate heating, has yielded significant findings. The study thoroughly investigated the effects of substrate temperature (Ts) on copper adhesion strength and morphology using the peel force test and electron microscopy. The peel force test was conducted at angles of 90°, 135°, and 180°. The average adhesion strength was about 0.2 N/mm for the samples without substrate heating. For the samples with substrate heating at 100 °C, the average peeling force of the electroplated copper film was about 1 N/mm. The average peeling force increased to 1.5 N/mm as the substrate heating temperature increased to 200 °C. The surface roughness increases as the annealing temperature of the Cu/AZO/Si sample increases. These findings not only provide a reliable and robust method for applying AZO transparent conductive films onto silicon solar cells but also underscore its potential to significantly enhance the efficiency and durability of solar cells significantly, thereby instilling confidence in the field of solar cell technology.

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.

Centrifugal Inertia-Induced Directional Alignment of AgNW Network for Preparing Transparent Electromagnetic Interference Shielding Films with Joule Heating Ability.

Transparent electromagnetic interference (EMI) shielding is highly desired in specific visual scenes, but the challenge remains in balancing their EMI shielding effectiveness (SE) and optical transmittance. Herein, this study proposed a directionally aligned silver nanowire (AgNW) network construction strategy to address the requirement of high EMI SE and satisfactory light transmittance using a rotation spraying technique. The orientation distribution of AgNW is induced by centrifugal inertia force generated by a high-speed rotating roller, which overcomes the issue of high contact resistance in random networks and achieves high conductivity even at low AgNW network density. Thus, the obtained transparent conductive film achieved a high light transmittance of 72.9% combined with a low sheet resistance of 4.5 Ω sq-1 and a desirable EMI SE value of 35.2dB at X band, 38.9dB in the K-band, with the highest SE of 43.4dB at 20.4GHz. Simultaneously, the excellent conductivity endowed the film with outstanding Joule heating performance and defogging/deicing ability, ensuring the visual transparency of windows when shielding electromagnetic waves. Hence, this research presents a highly effective strategy for constructing an aligned AgNW network, offering a promising solution for enhancing the performance of optical-electronic devices.

Preparation and characterization of ZnS/metal/ZnS transparent conductive multilayer films with different metal layers

ZnS/metal/ZnS transparent conductive multilayer films were deposited on quartz glass by pulsed laser deposition at room temperature with Au, Ag and Cu as the metal layers, and annealed in air at 100, 200 and 300℃ for 1 h. XRD patterns show that β -ZnS(111) diffraction peak of ZnS/Au/ZnS is stronger and sharper than the other two samples, indicating that its crystalline quality is the best. SEM images show the good structural homogeneity of the samples with smooth and compact film surfaces. When the annealing temperature increases from 100 to 300℃, the sheet resistance decreases first and then increases, while the carrier concentration changes in the opposite trend. The maximum transmittance (~85%) for ZnS/Au/ZnS in the visible light region is observed when the sample is annealed at 200℃. The figure of merit is calculated, and the best sample suitable for transparent conductive electrode is determined.

The Low-Attenuation Endfire Leaky-Wave State on an Optically Transparent Lossy Film

The development of high-performance optically transparent radio frequency (RF) radiators is limited by the intrinsic loss issue of transparent conductive films (TCFs). Instead of pursuing expensive endeavors to improve the TCFs’ electrical properties, this study introduces an innovative approach that leverages leaky-wave mode manipulation to mitigate the TCFs’ attenuating effect and maximize the RF radiation. Our finding reveals that the precise control of the mode confinement on glass-coated TCFs can create a low-attenuation window for leaky-wave propagation, where the total attenuation caused by TCF dissipation and wave leakage is effectively reduced. The observed low-attenuation leaky-wave state on lossy TCFs originates from the delicate balance between wave leakage and TCF dissipation, attained at a particular glass cladding thickness. By leveraging the substantially extended radiation aperture achieved under suppressed wave attenuation, this study develops an optically transparent antenna with an enhanced endfire realized gain exceeding 15 dBi and a radiation efficiency of 66%, which is validated to offer competitive transmission performance for advancing ubiquitous wireless communication and sensing applications.

Investigating the optical and electrical performance of rod coated silver nanowire-based transparent conducting films

Silver nanowires (Ag NWs) are highly promising building blocks for developing transparent conducting films (TCFs) due to their high electrical conductivity and good optical transparency. The large-scale production of Ag NW-based high-quality TCFs using low-cost processing methods can replace the traditional oxide based TCFs. Therefore, developing a reliable technique for large-scale fabrication of Ag NW-based TCFs is vital. This work involves the synthesis of Ag NWs, the fabrication of large-area Ag NW-based TCFs using a simple rod coating process, its optimization, and the performance analysis of the fabricated TCFs, including their demonstration as transparent heaters. The polyol synthesis method produces Ag NWs of lengths ranging from 25-110µm and diameters from 80-180 nm. The effect of Ag NW length, the number of coating passes, and the volume of the NW dispersion used per coating pass on the electrical and optical properties of the TCFs are studied by quantifying sheet resistance(Rs)and transmittance (T) of the film. The performance of the fabricated film is evaluated by estimating the figure of merit (FoM) in both percolative and bulk regimes. The TCF made with NWs of length 25.7µm and diameter 85.1 nm had the largest value of bulk FoM (101.3), percolative FoM (43.9), and, conductivity exponent (0.6). This elucidated the superior performance of the fabricated TCFs over those fabricated by other techniques. The critical thickness of the film (tmin), at the crossover between the percolation and bulk, scales with the shortest dimension of the NW, namely its diameter. The percolative FoM showed an increase, with a decrease in both sheet resistance and diameter of the NWs, with lowern. The fabricated TCF is tested as a transparent heater and the demonstration proves that rod coated Ag NW-based TCFs can be used for transparent electrode applications.

SnO2/Silver Nanowire/Polyimide Flexible Transparent Conductive Films for Double-Sided Perovskite Solar Cells and Heaters

SnO₂/Silver Nanowire/Polyimide Flexible Transparent Conductive Films for Double-Sided Perovskite Solar Cells and Heaters

Printable and filament-drawable PDMS based adhesive assisted manufacturing of highly conductive copper micro-patterns

Manufacturing of copper micro-patterns is crucial in electronics for its utilization as high conductivity transparent conductive films (TCFs) and circuits. In the preparation process of current TCFs, a plethora of materials have emerged that can replace traditional indium tin oxide (ITO). However, even for the most promising metal-based nanowire materials, there are issues such as high cost, complex welding, and high contact resistance. To address these problems, this paper proposes a printable and filament-drawable polydimethylsiloxane (PDMS)-based adhesive, which, through a novel additive patterning technology, efficiently and economically manufactures self-welding copper micro-meshes and circuits. The adhesive can be processed into micro-patterns through printing and filament drawing, on which ionic Ag can be in situ reduced and anchored, thereby eliminating the need for tedious pre- and post-treatment steps. The fully exposed Ag particles dramatically minimize the usage of precious metal catalyst, thus efficiently catalyzing electroless copper deposition (ECD) reaction. Highly conductive (1.03 × 107 S m−1) copper circuits can be fabricated on the printed adhesive patterns, exhibiting versatile applicability to diverse substrates. Highly precise copper micro-meshes (∼50 μm) can be fabricated on the filament networks drawn by the adhesive. The copper meshes undergo complete self-welding at junctions during the ECD process, thus exhibiting ultra-low square resistance of 0.45 Ω sq−1 while maintaining a high transmittance of 82.2 %. This is far superior to most of TCFs in published literature.

Conductive three-layer-stacked polycrystalline graphene intercalated with FeCl3

Graphene has attracted attention as a new transparent conductive film (TCF) because of its transparency, stability, strength, and versatility. However, it has a higher resistance than conventional TCFs. Recently, vapor transport intercalation with doping effect materials has been investigated to reduce the resistivity of graphene. Studies have revealed a correlation between the stacking structure and the intercalation efficiency, which favors smaller interactions between the graphene layers. In this study, polycrystalline graphene, which consists of small domains, grown by chemical vapor deposition is stacked in three layers using a layer-by-layer method, and the graphene layers are intentionally randomly stacked to suppress the interlayer interactions. Intercalation of FeCl3, which has p-type doping effects, into randomly stacked three-layer graphene (3LG) significantly reduces the sheet resistance (Rs) of 3LG from 500 to 41 Ω/sq. Interestingly, Raman mapping of the G peak shift of FeCl3 intercalated into randomly stacked 3LG indicates that in-plane intercalation proceeds homogeneously, even though strong interlayer interactions such as AB stacking are observed in some parts of 3LG. This study reveals that a randomly stacked polycrystalline graphene layer is advantageous for intercalation.

Polyelectrolyte-assisted uniform electron transporting layer on texture substrate for perovskite solar cells

Abstract Organic–inorganic halide perovskite solar cells using textured transparent conductive films exhibit high efficiencies with improved short-circuit current density. However, uniform electron transport layer (ETL) deposition on textures by solution process is challenging. In this study, uniform ETL were formed by sequentially spin- coating polyelectrolyte with positively and negatively charged segments and negative SnO2 colloid solution and electrostatically enhancing the SnO2 coverage. The stabilized power output (SPO) was improved from 12.9% to 18.6% by incorporating this polyelectrolyte/SnO2 bilayer.

Fabrication of Flexible Transparent Conductive Films via an Energy-Efficient In Situ Chemical Welding and Reinforcement Strategy.

Recently, flexible transparent conductive films composed of metal nanowires have received significant interest, particularly for flexible electronics. However, the high contact resistance among metal nanowires and the weak bonding effect between metal nanowires and substrates often result in films whose conductivity, adhesion, and flexibility fall short of the stringent requirements demanded by real-world uses. We developed a simple method to fabricate high-performance flexible transparent conductive films via successively spin-coating silver nanowires (AgNWs) and acidic silica sol onto the surface of the substrate. Under the capillary force of ethanol and the etching effect of hydrochloric acid, the adjacent AgNWs are induced to chemically weld in situ to form a stable network. The resulting composite film exhibits a sheet resistance of only 8.5 Ω/sq, marking an impressive 80% decrease compared with the pristine AgNW film. Meanwhile, the silica sol acts as a filler, improving light transmittance while further reinforcing the network structure and firmly bonding it to the substrate. Thus, the delamination of the nanowires under bending motion is effectively inhibited, and the resulting film was endowed with resistance remaining below 15 Ω/sq after 3000 bending and 200 tape peeling. The energy-efficient in situ chemical welding and reinforcement method for nanowires provides an innovative strategy for the batch preparation of flexible transparent conductive films.

Exploring cyclic olefin copolymer (COC) for flexible silver nanowire electrode

The development of flexible electronic devices has been a primary focus in various fields, and silver nanowire (Ag NW) networks show significant promise due to their unique electrical and mechanical properties. However, achieving well-defined and stable nanowire coatings on polymer substrates remains challenging. This work presents a novel and simple approach for directly coating Ag NWs on cyclic olefin copolymer (COC) substrates utilizing ultraviolet/ozone (UVO) treatment, a method not previously demonstrated for this specific material system up to our knowledge. The compatibility of this approach with COC eliminates the need for complex pre- and post-treatment processes, making it a more straightforward and environmentally friendly way to improve adhesion between Ag NWs and COC. The Ag NWs/COC electrodes exhibited excellent optoelectrical performance, with a high optical transmittance of 84% and a low sheet resistance of 13 Ω/sq—metrics that compare favorably to industry standards for transparent conductive films. Additionally, the Ag NWs/COC electrodes displayed excellent mechanical stability, showing no changes in sheet resistance after both tape adhesion and film bending tests. The novelty of the presented Ag NW-COC system, combined with the simplicity and environmental benefits of the UVO coating approach, as well as the demonstrated performance and stability of the resulting electrodes, make this work a significant advancement towards realizing the commercial potential of flexible electronics for biocompatible and wearable device applications.

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.

ZnO nanoarrays/Cu nanowires composite films with high haze value

In this work, we worked on compositing Cu nanowires (NWs) with ZnO nanoarrays (NAs) to enhance the light trapping abilities of transparent conductive films. A well-dispersed, crosslinked network of Cu NWs with appropriate light trapping ability was formed on the surface of the ZnO NAs, and the ZnO NAs/Cu NWs composite structures were obtained ultimately. The Cu NWs on the surface of the composite structures maintained excellent transparency and conductivity while preventing agglomeration phenomena. The ZnO NAs/Cu NWs composite films exhibited low average sheet resistance (59 Ω/sq) and high haze value (0.53) at 550 nm with uniform conductivity and exceptional light trapping performance. The composite films not only demonstrate enhanced light trapping abilities, but also exhibit improved electrical properties, making it an outstanding candidate for transparent front electrode materials in solar cell applications.

A new strategy for fabricating low haze p-type CuI film

As an intrinsic p-type transparent conductor with a wide band gap of 3.1 eV, γ-CuI full of potential has gradually attracted the attention of researchers. However, γ-CuI films deposited by various techniques generally exhibit high haze with a frosted glass-like appearance, which significantly affects the device performance. Herein, a new strategy is proposed in which true p-type CuI thin films with low haze have been successfully synthesised at room temperature. The specular transmittance of the CuI film over 85% in the visible region (400–800 nm) can be achieved. The haze of the as-prepared γ-CuI films can be as low as 0.7%. Meanwhile, the as-prepared CuI film has an FOM as high as 230 MΩ−1. This ideal stable p-type optoelectronic performance was significant among various typical p-type transparent conductive films.