Replace Indium Tin Oxide Research Articles

Improving the Performance of Transparent Conducting Electrodes Based on Cu Nanowires

The fabrication of transparent conducting electrodes (TCEs) is dominated by indium tin oxide (ITO). Some efforts are being made to find alternative materials as a substitute for ITO. Cu nanowire (CuNWs) is an equivalent candidate as a replacement for ITO but has a weakness that is easily oxidized. In this contribution, we report an increase in the performance of CuNWs, which can reduce the effect of oxidation. In this study, we provide a coating of CuNWs using PVP, PVA, and silver nanoparticles (AgNPs). The morphology, formation structure, and conductivity of CuNWs have been investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), and IV meter. The average length and diameter of the CuNWs were 5.5 μm and 120 nm, respectively. The transparent conducting has a stable conductivity after coating with PVP, PVA and AgNPs. The application of transparent conducting electrodes are sensors, electronic devices, solar cells, and organic light-emitting diodes (OLEDs).

Silver Nanowires (AgNWs) Post-Treatment Effect in Application of Flexible Transparent and Conductive Electrodes: A Mini Review

Transparent flexible electrodes (TFEs) are extremely crucial for expanding flexible and wearable electronic devices. Silver nanowires (AgNWs) have been extensively investigated as an alternative to replace Indium Tin Oxide (ITO) as a commercial TFE due to their high conductivity, transparency, and flexibility. AgNWs have replaced ITO-based electrodes as the preferred approach in flexible, transparent, and conductive electrodes (FTCE). AgNWs outperform other materials, such as Reduced Graphene Oxide (RGO), ceramic material, Carbon Nanotubes (CNT), and conductive polymers, in terms of electrical conductivity, transmittance, flexibility, and low sheet resistance. Numerous techniques, including as electrospinning, spray coating, spin coating, and doctor blades, are used to use AgNWs as flexible substrates. Seed-based growth and template-assisted synthesis are two fundamental synthesis techniques that could be used to generate AgNWs. However, poor adhesiveness, and thermal and electrical stability, begin to be bottlenecks for AgNWs as high deployment in a variety of devices. So AgNWs synthesis process began to shift to other methods, such as wet chemical and polyol. In this paper, short and clear summary of various advances including post-treatment methods such as UV radiation, microwave, sonication, quenching, and so on is conducted to be one step forward to test mechanical properties and to improve AgNWs performance.

MXene and AgNW based flexible transparent conductive films with sandwich structure for high-performance EMI shielding and electrical heaters

With the popularization of 5G technology and the development of science and technology, flexible and transparent conductive films (TCF) are increasingly used in the preparation of optoelectronic devices such as electromagnetic shielding devices, transparent flexible heaters, and solar cells. Silver nanowires (AgNW) are considered the best material for replacing indium tin oxide to prepare TCFs due to their excellent comprehensive properties. However, the loose overlap between AgNWs is a significant reason for the high resistance. This article investigates a sandwich structured conductive network composed of AgNW and Ti3C2Tx MXene for high-performance EMI shielding and transparent electrical heaters. Polyethylene pyrrolidone (PVP) solution was used to hydrophilic modify PET substrate, and then MXene, AgNW, and MXene were assembled layer by layer using spin coating method to form a TCF with a sandwich structure. One-dimensional AgNW is used to provide electron transfer channels and improve light penetration, while two-dimensional MXene nanosheets are used for welding AgNWs and adding additional conductive channels. The flexible TCF has excellent transmittance (85.1 % at 550 nm) and EMI shielding efficiency (27.1 dB). At the voltage of 5 V, the TCF used as a heater can reach 85.6 °C. This work offers an innovative approach to creating TCFs for the future generation.

Flexible Transparent Electrode Based on Ag Nanowires: Ag Nanoparticles Co-Doped System for Organic Light-Emitting Diodes.

Flexible organic light-emitting diodes (FOLEDs) have promising potential for future wearable applications because of their exceptional mechanical flexibility. Silver nanowire (Ag NW) networks are the most promising candidates to replace indium tin oxide (ITO), which is limited by its poor bendability. In this study, three different methods including methanol impregnation, argon plasma treatment, and ultraviolet radiation were used to reduce the junction resistance of Ag NWs to optimize the flexible transparent electrodes (FTEs); which were prepared using Ag NWs and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS). Then, the optoelectronic properties of the FTEs were further improved by using a co-doped system of silver nanowires and silver nanoparticles (Ag NPs), the structure of which consisted of PET/Ag NWs: Ag NPs/PEDOT: PSS/DMSO. The largest FOM value of 1.42 × 10-2 ohm-1 and a low sheet resistance value of 13.86 ohm/sq were obtained using the optimized FTEs. The prepared FOLED based on the optimized FTEs had a luminous efficiency of 6.04 cd/A and a maximum EQE of 1.92%, and exhibited no observed decline in efficiency when reaching maximum luminance. After 500 bending tests, the luminance still reached 82% of the original value. It is demonstrated that the FTEs prepared via the co-doped system have excellent optoelectronic properties as well as high mechanical stability.

Integration of Metal Meshes as Transparent Conducting Electrodes into Perovskite Solar Cells

AbstractAs the demand for photovoltaic technologies continues to grow, the quest for efficient and sustainable transparent conducting electrodes (TCEs) rapidly rises. Traditional solutions, such as indium tin oxide (ITO), face challenges related to indium scarcity and environmental impact. To tackle these issues, a novel metal mesh rear TCE consisting of gold micro‐meshes is developed as ITO replacement in perovskite solar cells (PSCs). This study reveals that optimized Au meshes can guarantee 75% of the extracted photocurrent compared to reference devices with ITO and a promising power conversion efficiency (PCE) of 8.65%. By utilizing hybrid mesh structures with a 10‐nm ITO layer, the PCE further improves to 12.1%, with the extracted current exceeding 80% of the reference. Metal meshes can even serve to replace the opaque metal contact of PSCs, amplifying their functionality and efficiency through bifacial and multi‐junction applications. Here, aerosol jet‐printed silver meshes serve as front electrodes, combined with either 5–10 nm of Au, achieving efficient semi‐transparent devices (PCE 16.8%), or with 5–10 nm of ITO, providing enhanced bifacial properties while maintaining competitive efficiency. Overall, this work highlights remarkable features of metal meshes, making them promising alternatives to commonly used TCEs in optoelectronic applications.

Effect of Cu addition on the optical, electrical, and structural properties of ultrathin Ag-based oxide/metal/oxide multilayer films

Ga and Al co-doped ZnO (GAZO) were used as oxide layers to fabricate GAZO/Ag/GAZO sandwich multilayer transparent conductive films. The effects of Cu addition in the middle layer on the optical, electrical, and structural properties of multilayer films were investigated. The influences of the Ag-Cu layer and GAZO layer thickness on the optical and electrical properties of multilayer films were further studied. The experimental results show that co-sputtering Cu and adding an ultrathin Cu seed layer changed the growth pattern of Ag films. GAZO/Ag-Cu/GAZO and GAZO/Cu/Ag/GAZO multilayer films exhibit high optical transparency and high electric conductivity. The annealing treatment can enhance the optical and electrical properties of the GAZO/Ag-Cu/GAZO and GAZO/Cu/Ag/GAZO multilayer films. The lowest sheet resistance of 9.49 Ω sq−1 and maximum average light transmittance in the visible range of 95.74 % can be obtained for the GAZO/Ag-Cu/GAZO films. The corresponding figure of merit is 68.18×10−3 Ω−1. The addition of Cu in the GAZO/Ag/GAZO multilayer films led to high transmittance and low resistivity, which can be used in various photoelectronic fields to replace indium tin oxide films.

Al-delta-doped ZnO films made by atomic layer deposition and flash-lamp annealing for low-emissivity coating

In this work, we have investigated and optimized the Al-delta-doped ZnO (δ -AZO) superlattices for mid-infrared applications. Thin films of δ -AZO are fabricated by atomic layer deposition (ALD) followed by millisecond-range (ms-range) flash-lamp annealing (FLA). During the FLA process, the superlattice structure is preserved and Al is electrically activated. The highest carrier concentration and lowest resistivity estimated from Hall-effect measurements are 2.7 × 1021 cm−3 and 8.8 × 10-4 Ωcm, respectively, for the δ -AZO superlattice with an Al:Zn ratio of 1:20. Moreover, glass substrates coated with the developed δ -AZO superlattice show a reflectance above 60 % in the near- and mid-infrared spectral range, while the transmittance in the visible range maintains above 80 %. The presented δ -AZO superlattice is a good alternative material to replace indium tin oxide films for cost-efficient low-emissivity glazing.

Recent Progress in All‐Solution‐Processed Organic Solar Cells

Comprehensive SummaryAll‐solution‐processed organic solar cells (OSCs) (from the bottom electrode to the top electrode) are highly attractive thanks to their low cost, lightweight and high‐throughput production. However, achieving highly efficient all‐solution‐processed OSCs remains a significant challenge. One of the key issues is the lack of high‐quality solution‐processed electrode systems that can replace indium tin oxide (ITO) and vacuum‐deposited metal electrodes. In this paper, we comprehensively review recent advances in all‐solution‐processed OSCs, and classified the devices as the top electrode materials, including silver nanowires (AgNWs), conducting polymers and composite conducting materials. The correlation between electrode materials, properties of electrodes, and device performance in all‐solution‐processed OSCs is elucidated. In addition, the critical roles of the active layer and interface layer are also discussed. Finally, the prospects and challenges of all‐solution‐processed OSCs are presented.

Solution-Processed ZnO with Conductivity over 1000 S cm-1 for ITO-Free Organic Photovoltaics.

Developing transparent conductors to replace indium tin oxide (ITO) is a critical objective in the field of organic optoelectronics. Non-atomically doped (NAD) ZnO thin films, while currently exhibiting limited conductivity, are highly promising candidates due to their unique advantages, such as having complete transparency in both the visible and near-infrared spectral regions, solution processability, and the desired surface electronic properties. In this work, the impact of surface modification by insulating polymers on the ultraviolet-enhanced conductivity of NAD-ZnO films is investigated. It was found that polymer modifiers that are rich in amino and hydroxyl groups are effective at increasing the concentration of oxygen vacancies and the conductivity of NAD-ZnO films. The highest conductivity of over 1000 S cm-1, which is more than twice as high as the previous record for NAD-ZnO films, is achieved using polyethylenimine ethoxylated (PEIE) to modify NAD-ZnO films. Subsequently, the replacement of ITO in organic photovoltaic devices by a ZnO/PEIE electrode is realized. The ZnO/PEIE-based OPV devices that were created exhibit performances comparable to those of ITO-based devices under simulated solar illumination and performances better than those achieved with ITO-based devices under simulated indoor illumination. These results make NAD-ZnO a promising candidate for the widespread replacement of ITO in optoelectronic devices.

Growth of SrMoO3 thin films by suboxide molecular beam epitaxy

Among ABO3 perovskites, SrMoO3 possesses the lowest electrical resistivity in addition to having high optical transparency in the visible spectrum. This unusual combination of material properties allows it to be a potential replacement for indium tin oxide as a transparent electrode. Thus far, its thin film synthesis has been challenging and limited primarily to pulsed laser deposition and sputtering. Here, we report the growth of SrMoO3 thin films by suboxide molecular beam epitaxy. We demonstrate that optically transparent and conductive SrMoO3 films can be grown by supplying elemental strontium via a conventional effusion cell and thermally evaporating MoO3 pellets as a molybdenum source. The direct supply of a molecular oxygen flux to the MoO3 charge was utilized to prevent reduction to lower oxidation states of the charge to ensure congruent evaporation and, thus, a stable MoO3 molecular flux. The optimal growth conditions were found by varying the Sr to MoO3 flux ratio determined from quartz crystal microbalance measurements and monitoring the growth by reflection high-energy electron diffraction. SrMoO3 thin films with 21 nm thickness were confirmed to be optically transparent with transmission between 75 and 91% throughout the visible spectral range and electrically conducting with a room temperature resistivity of 5.0 × 10−5 Ω cm. This realization of this thin film growth method can be further expanded to the growth of other transition metal perovskites in which cations have extremely low vapor pressure and cannot be evaporated in elemental forms.

Research on graphene and its application in touch screen

Graphene is a two-dimensional nanomaterial formed by the hybridization of carbon atoms. Graphene has become a popular new material in emerging industries because of its high conductivity, high toughness, high strength, high transparency, large specific surface area and other excellent properties. In view of the excellent properties and potential application value of graphene materials, a series of important progress has been made in semiconductor devices, transparent displays, sensors, capacitors, and other aspects. Graphene film light transmittance and conductivity is close to it ITO material, and can well solve the bottleneck of touch screen transparent electrode technology. It is one of the materials that replace Indium Tin Oxide (ITO) in flexible displays. Therefore, systematic research on graphene will play an important role in promoting the development of science and technology in the future. In this paper, the structure, properties, and development status of graphene are analyzed. Three traditional methods for preparing graphene films: mechanical peeling, chemical peeling, and chemical vapor deposition, and three novel process preparation methods: rotary spraying method, Plasma Enhanced Chemical Vapor Deposition (PECVD) method and layered self-assembly method are introduced. It summarizes the production process of graphene touch screen: transfer, modification, graphical, capacitive screen module preparation, its latest progress, and existing problems. Although preliminary studies have been conducted on the application of graphene films in various fields, the feasibility of its application has been verified, and it is expected to have significant advantages in some application fields, most of them are in the early stage of research and still face many technical challenges.

PEDOT:PSS Conductivity Enhancement through Addition of the Surfactant Tween 80.

Replacement of indium tin oxide with the intrinsically conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been of significant interest in recent years as a result of lower processing and material costs. In addition, the inclusion of additives has been reported to further enhance the conductivity, rheology, and wettability of PEDOT:PSS. In this study, Tween 80 was shown to decrease the sheet resistance of PEDOT:PSS films from approximately 1000 to 76 Ω□-1 at a 2.67 wt% surfactant concentration. Through X-ray diffraction, Raman spectroscopy, and atomic force microscopy, it was shown that the surfactant caused phase separation and structural ordering of the PEDOT and PSS components, leading to this improvement in conductivity. Furthermore, Tween 80 altered the rheological properties and decreased the surface tension of PEDOT:PSS, making coating common commodity polymers, often used as flexible substrates, more viable.

Predictive Modeling of Cracking Behaviors in Flexible Perovskite Solar Cells

Cracking behaviors within perovskite thin films are modeled through finite element analysis. Coupons of polyethylene terephthalate (PET), Indium Tin Oxide (ITO), and perovskite layers are deformed in three-point bend mode. Modeling gives insight into ranges for the physical properties of each layer due to gaps in literature inputs. The model proves the relationship between perovskite crystal size and its mechanical tolerance. Models with smaller crystals withstand more than 30% further displacement than those with crystals twice their size. A material replacement of ITO, the driving force causing cracking in films, is also modeled, and cracking within the perovskite layer occurred significantly later, showing an improved resilience to bending.

Graphene-Induced Performance Enhancement of Batteries, Touch Screens, Transparent Memory, and Integrated Circuits: A Critical Review on a Decade of Developments.

Highlights Graphene possesses high electronic mobility, minimal light absorbance, large surface area and exclusive mechanical properties. Graphene’s unique characteristics make it the perfect material for use in batteries, touch screens, transparent memory, and integrated circuits. The development of high-quality homogenous graphene, simple transfer processes, a lack of effective characterization methods, and high production costs prevent graphene from being widely used in the electronic industry. The production of large-area, nearly defect-free graphene using contemporary synthesis techniques, such CVD, holds great potential for the development of nanoelectronic devices.Graphene achieved a peerless level among nanomaterials in terms of its application in electronic devices, owing to its fascinating and novel properties. Its large surface area and high electrical conductivity combine to create high-power batteries. In addition, because of its high optical transmittance, low sheet resistance, and the possibility of transferring it onto plastic substrates, graphene is also employed as a replacement for indium tin oxide (ITO) in making electrodes for touch screens. Moreover, it was observed that graphene enhances the performance of transparent flexible electronic modules due to its higher mobility, minimal light absorbance, and superior mechanical properties. Graphene is even considered a potential substitute for the post-Si electronics era, where a high-performance graphene-based field-effect transistor (GFET) can be fabricated to detect the lethal SARS-CoV-2. Hence, graphene incorporation in electronic devices can facilitate immense device structure/performance advancements. In the light of the aforementioned facts, this review critically debates graphene as a prime candidate for the fabrication and performance enhancement of electronic devices, and its future applicability in various potential applications.

Transparent Conducting Films Based on Carbon Nanotubes: Rational Design toward the Theoretical Limit.

Electrically conductive thin‐film materials possessing high transparency are essential components for many optoelectronic devices. The advancement in the transparent conductor applications requires a replacement of indium tin oxide (ITO), one of the key materials in electronics. ITO and other transparent conductive metal oxides have several drawbacks, including poor flexibility, high refractive index and haze, limited chemical stability, and depleted raw material supply. Single‐walled carbon nanotubes (SWCNTs) are a promising alternative for transparent conducting films (TCFs) because of their unique and excellent chemical and physical properties. Here, the latest achievements in the optoelectronic performance of TCFs based on SWCNTs are analyzed. Various approaches to evaluate the performance of transparent electrodes are briefly reviewed. A roadmap for further research and development of the transparent conductors using “rational design,” which breaks the deadlock for obtaining the TCFs with a performance close to the theoretical limit, is also described.

Vibration and nonlinear dynamic response of nanocomposite multi-layer solar panel resting on elastic foundations

This paper dealt with the nonlinear dynamic response and vibration of multilayer organic solar panels subjected to mechanical and thermal loadings. The nanocomposite multilayer organic solar panel contains five layers which are manufactured by Al, P3HT: PCBM, PEDOT: PSS, Glass and Graphene which is a flexible replacement for indium tin oxide as a transparent and conducting electrode in the construction of solar panel. Based on classical theory, the basic equations are established by taking into account the effect of elastic foundations, von Kármán nonlinearity terms, and initial imperfection. The closed form expressions of the frequency–amplitude curves and natural frequency are obtained by using the Galerkin and Runger–Kutta methods. The numerical results illustrate positive effect of elastic foundations, negative effect of temperature increment and initial imperfection, considerable influence of geometrical parameters as well as excitation force on the free vibration and dynamic response of multilayer organic solar panel.

Wafer‐Scale Graphene Anodes Replace Indium Tin Oxide in Organic Light‐Emitting Diodes (Advanced Optical Materials 3/2022)

A novel use of large-area catalyst-free graphene to replace indium tin oxide (ITO) as an electrode in wafer-scale organic light emitting diodes is reported by Zhichao Weng, Colin J. Humphreys, William P. Gillin, and co-workers in article number 2101675. Indium is one of the nine rarest elements in the earth's crust. This research opens the door to replacing non-sustainable indium with sustainable graphene in optoelectronic devices.

Tunable physical properties of Al-doped ZnO thin films by O2 and Ar plasma treatments

Al-doped ZnO (AZO) is a promising transparent conducting oxide that can replace indium tin oxide (ITO) owing to its excellent flexibility and eco-friendly characteristics. However, it is difficult to immediately replace ITO with AZO because of the difference in their physical properties. Here, we study the changes in the physical properties of AZO thin films using Ar and O2 plasma treatments. Ar plasma treatment causes the changes in the surface and physical properties of the AZO thin film. The surface roughness of the AZO thin film decreases, the work function and bandgap slightly increase, and the sheet resistance significantly decreases. In contrast, a large work function change is observed in the AZO thin film treated with O2 plasma; however, the change in other characteristics is not significant. Therefore, the results indicate that post-treatment using plasma can accelerate the development of high-performance transparent devices.

Enhanced adhesion of Ag nanowire based transparent conducting electrodes for application in flexible electrochromic devices

Silver nanowires (Ag NWs) are currently the most likely to replace indium tin oxide (ITO) as flexible transparent conducting electrodes (FTCEs), but conventional preparation methods such as solution deposition will lead to weak conductivity and low adhesion to the substrate. In this work, polymethyl methacrylate (PMMA) as a superior mediate for the pressure embedding of Ag NW networks as transparent electrodes with 120 °C is demonstrated. The sheet resistance of the PMMA/Ag NWs FTCEs decreases from 32 Ω/sq. to 8.1 Ω/sq. at an optical transmittance of ~77.5 %. The calculated value of figures of merit ( FoM )is as high as 9.77 × 10 −3 Ω −1 . At the same time, after 10 min of ultrasonication and 30 times of wiping cycle, the sheet resistance is almost unchanged, indicating that the Ag NW networks have good adhesion to the flexible substrate. Meanwhile, the PMMA/Ag NWs FTCEs exhibit good mechanical flexibility with a bending radius up to 0.75 mm. Finally, the successful implementation of the PMMA/Ag NWs FTCEs into a flexible electrochromic device is demonstrated, verifying the applicability of PMMA/Ag NWs FTCEs. • High-reliable PMMA/AgNW FTCEs are obtained by hot lamination process. • PMMA/AgNW FTCEs show simultaneously improved conductivity and adhesion. • Resistance does not show significant change after ultrasonication and wiping test. • Flexible electrochromic device based on FTCEs is prepared and demonstrated.

Flexible and transparent silver nanowires/biopolymer film for high-efficient electromagnetic interference shielding

Flexible and transparent conductive films are highly desirable in some optoelectronic devices, such as smart windows, touch panels, as well as displays and electromagnetic protection field. Silver nanowire (Ag NW) has been considered as the best material to replace indium tin oxide (ITO) to fabricate flexible transparent electromagnetic interference (EMI) shielding films due to its superior comprehensive performance. However, the common substrates supporting Ag NWs require surface modification to enhance the adhesion with Ag NWs. In this work, a flexible and transparent Ag NWs EMI shielding film with sandwich structure through a facile rod-coating method, wherein Ag NWs network were embedded between biodegradable gelatin-based substrate and cover layer. The interfacial adhesion between Ag NWs and gelatin-based layers was enhanced by hydrogen-bonding interaction and swelling effect without any pretreatment. The shielding effectiveness (SE) of the G/Ag NW/G (G represents gelatin-based layer) film reaches 37.74 dB at X band with an optical transmittance of 72.0 %. What’s more, the flexible gelatin-based layer and encapsulated structure endow the resultant G/Ag NW/G film integrating excellent mechanical properties, reliable durability, antioxidation, as well as anti-freezing performance. This work paves a new way for fabricating flexible transparent EMI shielding films.