Wearable and Wavelength-Tunable Near-Infrared Organic Light-Emitting Diodes for Biomedical Applications.

Near-infrared organic light-emitting diodes (NIR OLEDs) have significant potential for wearable phototherapeutic applications because of the unique properties of the OLEDs, including their free-form electronics and the excellent biomedical effects of NIR emission. In spite of their tremendous promise, given that the majority of NIR OLEDs in previous research have relied on the utilization of an intrinsically brittle indium tin oxide (ITO) electrode, their practicality in the field of wearable electronics is inherently constrained. Here, we report wearable and wavelength-tunable NIR OLEDs that employ a high-performance NIR emitter and an innovative architecture by replacing the ITO with a silver (Ag) electrode. The NIR OLEDs permit wavelength tuning of emissions from 700 to 800 nm and afford stable operation even under repeated bending conditions. The NIR OLEDs provide a lowered device temperature of 37.5 °C even during continuous operation under several emission intensities. In vitro experiments were performed with freshly fabricated NIR OLEDs. The outcomes were evaluated against experimental results performed using the same procedure utilizing blue, green, and red OLEDs. When exposed to NIR light irradiation, the promoting effect of cell proliferation surpassed the proliferative responses observed under the influence of visible light irradiation. The proliferation effect of human hair follicle dermal papilla cells is clearly related to the irradiation wavelength and time, thus underscoring the potential of wavelength-tunable NIR OLEDs for efficacious phototherapy. This work will open novel avenues for wearable NIR OLEDs in the field of biomedical application.

Study of mechanical degradation of freestanding ALD Al2O3 by a hygrothermal environment and a facile protective method for environmentally stable Al2O3: toward highly reliable wearable OLEDs.

Al2O3 deposited via atomic layer deposition (ALD) has been used as an insulating and barrier film for thin-film transistors, organic electronics, and microelectromechanical systems. However, ALD Al2O3 films are easily degraded by hydrolysis under harsh hygrothermal conditions, owing to their poor environmental stability. In this study, the mechanical properties and water-vapor transmission rate (WVTR) of environmentally degraded Al2O3 films were investigated by varying the temperature and relative humidity (RH). The hygrothermal environment led to surface and pinhole-concentrated degradation based on aluminum hydroxide, which caused an increased WVTR and reduced elongation of the films in harsher environments. In particular, the elongation of the degraded Al2O3 films was reduced to 0.3%, which is one-third of that of as-deposited Al2O3, and their WVTR increased on the order of 10-1 g m-2 day-1, which is more than 1000 times that of as-deposited Al2O3. Therefore, we introduced a functional silane-based inorganic-organic hybrid layer (silamer) onto the Al2O3 films to improve their environmental stability. The silamer helped preserve the characteristics of Al2O3 films by forming a strong and continuous aluminate phase of Al-O-Si at their interface in hygrothermal environments. Furthermore, the silamer-capped Al2O3 was shown to be an environmentally stable encapsulation for application in wearable organic devices.

Highly Air-Stable, Flexible, and Water-Resistive 2D Titanium Carbide MXene-Based RGB Organic Light-Emitting Diode Displays for Transparent Free-Form Electronics.

Flexible see-through displays are considered to be the next generation smart display, providing improved information flow, safety, situational awareness, and overall user experience in smart windows, automotive displays, glass-form biomedical displays, and augmented reality systems. 2D titanium carbides (MXenes) are promising material as electrodes of the transparent and flexible displays due to their high transparency, metallic conductivity, and flexibility. However, current MXene-based devices have insufficient air stability and lack engineering schemes to develop matrix-addressable display forms with sufficient pixels to display information. Here, we develop an ultraflexible and environmentally stable MXene-based organic light-emitting diode (OLED) display by combining high performance MXene electrodes, flexible OLEDs, and ultrathin and functional encapsulation systems. The MXene material was synthesized and used to fabricate a highly reliable MXene-based OLED that can stably operate in air condition for over 2000 h, endure repetitive bending deformation of 1.5 mm radius, and maintain environmental stability for 6 h when exposed to wet surroundings. The RGB MXene-based OLEDs were fabricated, (1691 cd m-2 at 40.4 mA cm-2 for red, 1377 cd m-2 at 4.26 mA cm-2 for green, and 1475 cd m-2 at 18.6 mA cm-2 for blue) and a matrix-addressable transparent OLED display was demonstrated that could display letters and shapes.

Fiber-based quantum-dot pulse oximetry for wearable health monitoring with high wavelength selectivity and photoplethysmogram sensitivity.

Increasing demand for real-time healthcare monitoring is leading to advances in thin and flexible optoelectronic device-based wearable pulse oximetry. Most previous studies have used OLEDs for this purpose, but did not consider the side effects of broad full-width half-maximum (FWHM) characteristics and single substrates. In this study, we performed SpO2 measurement using a fiber-based quantum-dot pulse oximetry (FQPO) system capable of mass production with a transferable encapsulation technique, and a narrow FWHM of about 30 nm. Based on analyses we determined that uniform angular narrow FWHM-based light sources are important for accurate SpO2 measurements through multi-layer structures and human skin tissues. The FQPO was shown to have improved photoplethysmogram (PPG) signal sensitivity with no waveguide-mode noise signal, as is typically generated when using a single substrate (30-50%). We successfully demonstrate improved SpO2 measurement accuracy as well as all-in-one clothing-type pulse oximetry with FQPO.

Heteroleptic Ir(III)-based near-infrared organic light-emitting diodes with high radiance capacity.

Near-infrared organic light-emitting diodes (NIR OLEDs) with heavy metals are regularly reported due to the advantages of their various applications in healthcare services, veil authentication, and night vision displays. For commercial applications, it is necessary to look at radiance capacity (RC) instead of radiance because of power consumption. However, recent papers still reported only simple high radiance performance and do not look at device from the point of view of RC. To overcome this hurdle, we designed Ir(III)-based heteroleptic NIR materials with two types of auxiliary ligand. The proposed emitters achieve a highly oriented horizontal dipole ratio (Ir(mCPDTiq)2tmd, complex 1: 80%, Ir(mCPDTiq)2acac, complex 2: 81%) with a short radiative lifetime (1: 386 ns, 2: 323 ns). The device also shows an extremely low turn-on voltage (Von) of 2.2 V and a high RC of 720 mW/sr/m2/V. The results on the Von and RC of the device is demonstrated an outstanding performance among the Ir(III)-based NIR OLEDs with a similar emission peak.

Wearable Photomedicine for Neonatal Jaundice Treatment Using Blue Organic Light-Emitting Diodes (OLEDs): Toward Textile-Based Wearable Phototherapeutics.

Neonatal jaundice is a very common disease in newborns and can lead to brain damage or death in severe cases. Phototherapy with light-emitting diode (LED) arrays is widely used as the easiest and fastest way to relieve jaundice in newborns, but it has distinct disadvantages such as loss of water in the patient, damage to the retina, and separation from parents. In this paper, a novel light source-based phototherapy for neonatal jaundice is proposed using a textile-based wearable organic light-emitting diode (OLED) platform that can move flexibly and conform to the curvature of the human body. The soft and flexible textile-based blue OLED platform is designed to have a peak wavelength of 470 nm, suitable for jaundice treatment, and shows performance (>20 µW cm-2 nm- 1 ) suitable for intensive jaundice treatment even at low voltage (<4.0 V). The textile-based OLEDs fabricated in this study exhibit an operating reliability of over 100 h and low-temperature operation (<35 °C). The results of an in vitro jaundice treatment test using a large-area blue OLED confirm that the bilirubin level decreases to 12 mg dL-1 with 3 h of OLED irradiation.

Cell proliferation effect of deep-penetrating microcavity tandem NIR OLEDs with therapeutic trend analysis.

Long wavelengths that can deeply penetrate into human skin are required to maximize therapeutic effects. Hence, various studies on near-infrared organic light-emitting diodes (NIR OLEDs) have been conducted, and they have been applied in numerous fields. This paper presents a microcavity tandem NIR OLED with narrow full-width half-maximum (FWHM) (34 nm), high radiant emittance (> 5 mW/cm2) and external quantum efficiency (EQE) (19.17%). Only a few papers have reported on biomedical applications using the entire wavelength range of the visible and NIR regions. In particular, no biomedical application studies have been reported in the full wavelength region using OLEDs. Therefore, it is worth researching the therapeutic effects of using OLED, a next-generation light source, and analyzing trends for cell proliferation effects. Cell proliferation effects were observed in certain wavelength regions when B, G, R, and NIR OLEDs were used to irradiate human fibroblasts. The results of an in-vitro experiment indicated that the overall tendency of wavelengths is similar to that of the cytochrome c oxidase absorption spectrum of human fibroblasts. This is the first paper to report trends in the cell proliferation effects in all wavelength regions using OLEDs.

High-Performance and Reliable White Organic Light-Emitting Fibers for Truly Wearable Textile Displays.

Light-emitting fibers have been intensively developed for the realization of textile displays and various lighting applications, as promising free-form electronics with outstanding interconnectivity. These advances in the fiber displays have been made possible by the successful implementation of the core technologies of conventional displays, including high optoelectronic performance and essential elements, in the fiber form-factor. However, although white organic light-emitting diodes (WOLEDs), as a fundamental core technology of displays, are essential for realizing full-color displays and solid-state lighting, fiber-based WOLEDs are still challenging due to structural issues and the lack of approaches to implementing WOLEDs on fiber. Herein, the first fiber WOLED is reported, exhibiting high optoelectronic performance and a reliable color index, comparable to those of conventional planar WOLEDs. As key features, it is found that WOLEDs can be successfully introduced on a cylindrical fiber using a dip-coatable single white-emission layer based on simulation and optimization of the white spectra. Furthermore, to ensure durability from usage, the fiber WOLED is encapsulated by an Al2 O3 /elastomer bilayer, showing stable operation under repetitive bending and pressure, and in water. This pioneering work is believed to provide building blocks for realizing complete textile display technologies by complementing the lack of the core technology.

Unveiling the Annealing-Dependent Mechanical Properties of Freestanding Indium Tin Oxide Thin Films.

A fundamental understanding of the mechanical behavior of the indium tin oxide (ITO) layer is very important because cracking and delamination of the ITO layers have been a critical obstacle for mechanically robust flexible electronics. In this study, the intrinsic mechanical properties of ITO thin films without a substrate were measured by utilizing a freestanding tensile testing method. Young's modulus (89 ± 1 GPa), elongation (0.34 ± 0.02%), and tensile strength (293 ± 13 MPa) of amorphous as-deposited ITO thin films were successfully measured. The sheet resistance, transparency, and thickness of the as-deposited films were 32.9 ± 0.5 Ω/sq, 92.7% (400-700 nm), and 152 ± 6 nm, respectively. First, we investigated the effects of annealing temperature on the mechanical properties of ITO thin films. For 100- and 150 °C-annealed ITO thin films, which were amorphous, Young's modulus, elongation, and tensile strength were enhanced by increasing the packing density and reducing the structural defects. For 200 °C-annealed ITO thin films, which were polycrystalline, Young's modulus was further increased because of their highly packed crystalline nature. However, there was a significant decrease in elongation and tensile strength because grain boundaries act as critical defects. Next, the annealing time was varied from 0.5 to 6 h for a better understanding of the effects of the annealing time. As a result, the maximum elongation (0.54 ± 0.03%) and tensile strength (589 ± 11 MPa) were obtained at 150 °C for 1 h. Annealing for 1 h was appropriate for sufficient defect reduction; however, excessive annealing for more than 1 h increased the degree of partial crystallization of the ITO thin films. The proposed annealing conditions and the corresponding mechanical properties provide guidelines for the optimum annealing process of ITO thin films and quantitative data for mechanical analysis to design mechanically robust flexible electronics.

Parallel-Stacked Flexible Organic Light-Emitting Diodes for Wearable Photodynamic Therapeutics and Color-Tunable Optoelectronics.

Deformable organic light-emitting diode (OLED) based optoelectronic devices hold promise for various wearable applications including biomedical systems and displays, but current OLED technologies require high voltage and lack the power needed for wearable photodynamic therapy (PDT) applications and wearable displays. This paper presents a parallel-stacked OLED (PAOLED) with high power, more than 100 mW/cm2, at low voltage (<8 V). The current dispersion ratio can be tuned by optimizing the structure of the individual OLEDs stacked to create the PAOLED, allowing control of the PAOLED's wavelength shapes, current efficiency, and power. In this study, a fabricated PAOLED operated reliably for 100 h at a high power of 35 mW/cm2. Confirming its potential application to PDT, the measured singlet oxygen generation ratio of the PAOLED was found to be 3.8 times higher than the reference OLED. The high-power PAOLED achieved a 24% reduction in melanoma cancer cell viability after a short (0.5 h) irradiation. In addition, a white light PAOLED with color tuning was realized through OLED color combination, and a high brightness of over 30 000 cd/m2 was realized, below 8.5 V. In conclusion, the PAOLED was demonstrated to be suitable for a variety of low-voltage, high-power wearable optoelectronic applications.

Organic Light-Emitting Diodes: Pushing Toward the Limits and Beyond.

Organic light-emitting diodes (OLEDs) are established as a mainstream light source for display applications and can now be found in a plethora of consumer electronic devices used daily. This success can be attributed to the rich luminescent properties of organic materials, but efficiency enhancement made over the last few decades has also played a significant role in making OLEDs a practically viable technology. This report summarizes the efforts made so far to improve the external quantum efficiency (EQE) of OLEDs and discusses what should further be done to push toward the ultimate efficiency that can be offered by OLEDs. The study indicates that EQE close to 58% and 80% can be within reach without and with additional light extraction structures, respectively, with an optimal combination of cavity engineering, low-index transport layers, and horizontal dipole orientation. In addition, recent endeavors to identify possible applications of OLEDs beyond displays are presented with emphasis on their potential in wearable healthcare, such as OLED-based pulse oximetry as well as phototherapeutic applications based on body-attachable flexible OLED patches. OLEDs with fabric-like form factors and washable encapsulation strategies are also introduced as technologies essential to the success of OLED-based wearable electronics.

Two-Dimensionally Stretchable Organic Light-Emitting Diode with Elastic Pillar Arrays for Stress Relief.

Recent advanced studies on flexible and stretchable electronic devices and optoelectronics have made possible a variety of soft and more functional electronic devices. With consumer demand for highly functional or free-form displays, high flexibility and stretchability in light-emitting devices are needed. Herein, we developed a unique structure of stretchable substrates with pillar arrays to reduce the stress on the active area of devices when strain is applied. We confirmed the advantages of the produced structures using mechanical simulation tools and determined that the structures effectively lessen the applied stress of interconnection as well as the active area in a stretched state. With this stress-relief stretchable substrate, we realized stretchable OLEDs that are compliant and maintain their performance under high strain deformation. Also, devices can be stretched in the biaxis, which is superior to only one-directional stretchable electronics; as such, devices can be used in practical applications like wearable electronics and health monitoring systems. We propose, for the first time, stretchable OLEDs patterned by the thermal evaporation fabrication process onto stress-relief substrates. These OLEDs can mitigate certain problems in previous studies of stretchable OLEDs without need to find new materials or to use a prestrained fabrication process.

Fibertronic Organic Light-Emitting Diodes toward Fully Addressable, Environmentally Robust, Wearable Displays.

Significant potential of electronic textiles for wearable applications has triggered active studies of luminescent fibers toward smart textile displays. In spite of notable breakthroughs in the lighting fiber technology, a class of information displays with a luminescent fiber network is still underdeveloped due to several formidable challenges such as limited electroluminescence fiber performance, acute vulnerability to chemical and mechanical factors, and lack of decent engineering schemes to form fibers with robust interconnectable pixels for two-dimensional matrix addressing. Here, we present a highly feasible strategy for organic light-emitting diode (OLED) fiber-based textile displays that can overcome these issues by implementing prominent solution options including compatible fabrication method of OLED pixel arrays on adapted fiber configurations and chemically/mechanically sturdy but electrically conductive passivation system. To create solid interconnectable OLED fibers without compromising the high electroluminescence performance, phosphorescence OLED materials are deposited onto process-friendly fibers of rectangular stripes, where periodically patterned OLED pixels are selectively passivated with robust polymer and circumventing metal pads by a stamp-assisted printing method. A woven textile of interlaced interconnectable OLED fibers with perpendicularly arranged conductive fibers serves as a matrix-addressable two-dimensional network that can be operated by the passive matrix scheme. Successful demonstrations of stably working woven OLED textile in the water, as well as under the applied tensile force, support feasibility of the present approach to reify fully addressable, environmentally durable, fiber-based textile displays.

Recent Progress of Fiber Shaped Lighting Devices for Smart Display Applications-A Fibertronic Perspective.

Advances in material science and nanotechnology have fostered the miniaturization of devices. Over the past two decades, the form-factor of these devices has evolved from 3D rigid, volumetric devices through 2D film-based flexible electronics, finally to 1D fiber electronics (fibertronics). In this regard, fibertronic strategies toward wearable applications (e.g., electronic textiles (e-textiles)) have attracted considerable attention thanks to their capability to impart various functions into textiles with retaining textiles' intrinsic properties as well as imperceptible irritation by foreign matters. In recent years, extensive research has been carried out to develop various functional devices in the fiber form. Among various features, lighting and display features are the highly desirable functions in wearable electronics. This article discusses the recent progress of materials, architectural designs, and new fabrication technologies of fiber-shaped lighting devices and the current challenges corresponding to each device's operating mechanism. Moreover, opportunities and applications that the revolutionary convergence between the state-of-the-art fibertronic technology and age-long textile industry will bring in the future are also discussed.

Sandwich-structure transferable free-form OLEDs for wearable and disposable skin wound photomedicine.

Free-form optoelectronic devices can provide hyper-connectivity over space and time. However, most conformable optoelectronic devices can only be fabricated on flat polymeric materials using low-temperature processes, limiting their application and forms. This paper presents free-form optoelectronic devices that are not dependent on the shape or material. For medical applications, the transferable OLED (10 µm) is formed in a sandwich structure with an ultra-thin transferable barrier (4.8 µm). The results showed that the fabricated sandwich-structure transferable OLED (STOLED) exhibit the same high-efficiency performance on cylindrical-shaped materials and on materials such as textile and paper. Because the neutral axis is freely adjustable using the sandwich structure, the textile-based OLED achieved both folding reliability and washing reliability, as well as a long operating life (>150 h). When keratinocytes were irradiated with red STOLED light, cell proliferation and cell migration increased by 26 and 32%, respectively. In the skin equivalent model, the epidermis thickness was increased by 39%; additionally, in organ culture, not only was the skin area increased by 14%, but also, re-epithelialization was highly induced. Based on the results, the STOLED is expected to be applicable in various wearable and disposable photomedical devices.

Plasmonically Engineered Textile Polymer Solar Cells for High-Performance, Wearable Photovoltaics.

A practically applicable type of wearable polymer solar cells (PSCs) is presented with the enhanced performance by exploiting simply embodied, plasmonic nanostructures on a commercially available textile platform of optically opaque, geometrically uneven, and physically permeable woven fabrics that are commonly not compatible with organic photovoltaics. On a conformable fabric substrate preferentially processed with organic/inorganic multilayers for both planarization and encapsulation, the fabrication of top-illuminated, inverted type of PSCs with a transparent top electrode consisting of optimized dielectric/metal/dielectric multilayers is conducted, where a nanostructure of disorderly distributed elliptical hemispheres is implanted at an opaque bottom silver electrode by spin-coated silica nanoparticles in advance of depositing this electrode. The nanostructured bottom electrode promotes the light trapping effect at wavelengths of the surface plasmon resonance, as well as reduces the electrical Ohmic loss, thereby achieving a device with the power conversion efficiency of ∼8.71% at the given plasmonic device, where a net improvement of the efficiency is ∼1.46% compared to the planar device comprising otherwise same constituent layers. Systematic studies on optical properties and associated photovoltaic performance in experiments, together with analytic numerical modeling, allow quantitative understanding of the underlying physics, providing optimal rules for tailoring random nanostructures to the textile PSCs in the context of high-performance wearable photovoltaics.

Low-Temperature and Corrosion-Resistant Gas Diffusion Multibarrier with UV and Heat Rejection Capability-A Strategy to Ensure Reliability of Organic Electronics.

When placed in an outdoor environment, organic electronic devices (OEDs) can degrade on exposure to moisture, UV light, and heat, owing to the chemical sensitivity and decomposition of the organic materials. Therefore, to protect OEDs from outdoor environments, thin-film passivation, which can block harmful elements from reaching organic materials, is required. To meet the demands and trends in encapsulation technologies, in this study, we developed a low-temperature, simple, and effective gas diffusion multibarrier (GDM), which is UV and heat reflective as well as corrosion resistant. The designed UV- and heat-reflective GDM (UHGDM) has a multistacked structure in the form of a UV filter/Ag/gas diffusion barrier (GDB)/polymer based on a dielectric/metal/dielectric (DMD) configuration. First, the DMD structure was used as a heat mirror for infrared reflectance. Second, the bottom dielectric layer of the DMD structure was used as the UV filter, and it consisted of a ZnS/LiF multistacked structure with large differences in refractive indexes. Third, a nanolaminate-based GDB barrier with multi-interfacial and defect-decoupling systems, which achieved a water vapor transmission rate of 1.58 × 10-5 g/m2/day at a thickness of 60 nm, was used as the top dielectric layer of the DMD structure. Finally, an inorganic/organic hybrid polymer layer was coated on the DMD structure to provide corrosion-resistance and waterproofing properties. The fabricated UHGDM showed high transparency in the visible region and excellent reflectance in the UV and IR regions, resulting in excellent UV and heat rejection capability in practical UV and heat reflection tests. In addition to optical functionalities, the UHGDM maintained its functionality against harsh environmental conditions because of the GDB/polymer structure. Finally, the feasibility of the UHGDM was demonstrated using organic solar cells through water immersion and shelf lifetime tests.

Design of Highly Water Resistant, Impermeable, and Flexible Thin-Film Encapsulation Based on Inorganic/Organic Hybrid Layers.

The lack of a transparent, flexible, and reliable encapsulation layer for organic-based devices makes it difficult to commercialize wearable, transparent, flexible displays. The reliability of organic-based devices sensitive to water vapor and oxygen must be guaranteed through an additional encapsulation layer for the luminance efficiency and lifetime. Especially, one of the major difficulties in current and future OLED applications has been the absence of thin-film encapsulation with superior barrier performance, mechanical flexibility, and water-resistant properties. In this work, we fabricated highly water-resistant, impermeable, and flexible inorganic/organic multilayers with optimized Al2O3 and functional organic layers. The key properties of the fabricated multilayers were compared according to the thickness and functionality of the inorganic and organic layers. Improvement of the barrier performance is mainly attributed to the optimized thickness of the Al2O3 films, and is additionally due to the increased lag time and effective surface planarization effects caused by the use of micrometer-thick organic layers. As a result, the 3-dyad multilayer structure composed of 60 nm-thick Al2O3 layers deposited at 70 °C and 2-µm-thick silane-based inorganic/organic hybrid polymer (silamer) layers with layered silica exhibited the lowest WVTR value of 1.11 × 10-6 g/m2/day in storage conditions of 30 °C/90% relative humidity. In addition, the multibarrier exhibited good mechanical stability through the use of alternating stacks of brittle inorganic and soft organic layers, without showing a large increase in the WVTR after bending tests. In addition, silamer layers improved the environmental stability of the Al2O3 ALD film. The silamer layer coated on the Al2O3 film effectively worked as a protective layer against harsh environments. The effective contact at the interface of Al2O3/silamer makes the barrier structure more impermeable and corrosion-resistant. In this study, we not only demonstrated an optimized multilayer based on functional organic layers but also provided a methodology for designing a wearable encapsulation applicable to wearable organic electronics.

Robust Transparent and Conductive Gas Diffusion Multibarrier Based on Mg- and Al-Doped ZnO as Indium Tin Oxide-Free Electrodes for Organic Electronics.

Thin-film encapsulation is strictly required to protect transparent, flexible organic light-emitting diodes (OLEDs) based on plastic substrates with poor moisture barrier performances against water vapor and oxygen. However, additional encapsulation process makes OLED fabrication complex and expensive, resulting in lower yield and higher costs for the manufacture of OLEDs. Therefore, to develop simple, transparent conductive gas diffusion barrier (TCGDB) technologies by providing barrier performances to electrodes can be alternatives. Furthermore, TCGDB based on dielectric/metal/dielectric structures exhibit not only excellent barrier performances to protect metallic and organic layers against the ambient environment but also mechanical flexibility overcoming the brittleness of oxides. In this work, to improve the moisture-resistant, electrical, and optical properties of ZnO film, periodical dopant layers were inserted during the deposition of atomic layer deposition ZnO film. These dopant layers make the intrinsic ZnO film more optically and electrically functional. The dopant of MgO with a wide band gap enables blue-shifted optical transmittance, and the dopant of Al atoms makes doped ZnO more electrically conductive. In addition, these dopant layers in the ZnO film interrupt the film crystallization, making the film less crystalline with fewer channels and grain boundaries. This effect results in significant improvement of its GDB properties. With a functional and material design that takes full advantage of the synergetic combination of highly flexible conductive Ag and a moisture-resistant MAZO layer, the MAZO/Ag/MAZO (MAM) multilayer with a thickness of approximately 110 nm achieves a sheet resistance of 5.60 Ω/sq, an average transmittance of 89.72% in the visible range, and a water vapor transmission rate on the order of 10-5 g/m2/day. In addition, OLEDs with the MAM electrode demonstrated a great potential of indium tin oxide- and encapsulation-free organic electronics.

Author Correction: Plasmonic Chromatic Electrode with Low Resistivity.

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.