Ultra‑Transparent and Multifunctional IZVO Mesh Electrodes for Next‑Generation Flexible Optoelectronics

Mechanically durable transparent electrodes are essential for achieving long-term stability in flexible optoelectronic devices.Furthermore,they are crucial for applications in the fields of energy,display,healthcare,and soft robotics.Conducting meshes represent a promising alternative to traditional,brittle,metal oxide conductors due to their high electrical conductivity,optical transparency,and enhanced mechanical flexibility.In this paper,we present a simple method for fabricating an ultra-transparent conducting metal oxide mesh electrode using selfcracking-assisted templates.Using this method,we produced an electrode with ultra-transparency(97.39%),high conductance(Rs=21.24Ωsq^(−1)),elevated work function(5.16 eV),and good mechanical stability.We also evaluated the effectiveness of the fabricated electrodes by integrating them into organic photovoltaics,organic light-emitting diodes,and flexible transparent memristor devices for neuromorphic computing,resulting in exceptional device performance.In addition,the unique porous structure of the vanadium-doped indium zinc oxide mesh electrodes provided excellent flexibility,rendering them a promising option for application in flexible optoelectronics.

Stably doped graphene transparent electrode with improved lightextraction for efficient flexible organic light-emitting diodes

Graphene-based flexible transparent electrodes(FTEs)are promising candidate materials for developing next-generation flexible organic light-emitting diodes(OLEDs).However,the quest for high-efficiency OLEDs is hindered by the low light-extraction and charge injection efficiencies of graphene electrode.Here,we combine the frustrated Lewis pair doping with nanostructure engineering to obtain high-performance graphene FTE.A p-type dopant aci-nitromethane-tris(pentafluorophenyl)borane(ANBCF)was synthesized and deposited on graphene FTE to form an aperiodic nanostructure,which not only improves the light-extraction but also stably p-dopes graphene to enhance its hole injection.The use of ANBCF-doped graphene as the anode enables high-efficiency flexible green OLEDs with external quantum efficiency(EQE)and power efficiency(PE)out-performing most flexible graphene OLEDs of comparable structure.This study provides a simple and effective pathway to fabricate high-performance graphene FTEs for efficient flexible OLEDs.

Photonic crystal slabs in flexible organic light-emitting diodes

Photonic crystal slabs integrated into organic light-emitting diodes(OLEDs) allow for the extraction of waveguide modes and thus an increase in OLED efficiency. We fabricated linear Bragg gratings with a 460-nm period on flexible polycarbonate substrates using UV nanoimprint lithography. A hybrid organic–inorganic nanoimprint resist is used that serves also as a high refractive index layer. OLEDs composed of a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate(PEDOT:PSS) polymer anode, an organic emission layer [poly(p-phenylene vinylene)(PPV)-derivative 'Super Yellow'], and a metal cathode(Li F/Al) are deposited onto the flexible grating substrates. The effects of photonic crystal slab deformation in a flexible OLED are studied in theory and experiment. The substrate deformation is modeled using the finite-element method. The influence of the change in the grating period and the waveguide thickness under bending are investigated. The change in the grating period is found to be the dominant effect. At an emission angle of 20° a change in the resonance wavelength of 1.2% is predicted for a strain of 1.3% perpendicular to the grating grooves. This value is verified experimentally by analyzing electroluminescence and photoluminescence properties of the fabricated grating OLEDs.

Materials and devices for flexible and stretchable photodetectors and light-emitting diodes

Recently,significant efforts have been directed at overcoming the limitations of conventional rigid optoelectronic devices,particularly their poor mechanical stability under bending,folding,and stretching deformations.One of major approaches for rendering optoelectronic devices mechanically deformable is to replace the conventional electronic/optoelectronic materials with functional nanomaterials or organic materials that are intrinsically flexible/stretchable.Further,advanced device designs and unconventional fabrication methods have also contributed to the development of soft optoelectronic devices.Accordingly,new devices such as bio-inspired curved image sensors,wearable light emitting devices,and deformable bio-integrated optoelectronic devices have been developed.In this review,recent progress in the development of soft optoelectronic materials and devices is outlined.First,various materials such as nanomaterials,organic materials,and their hybrids that are suitable for developing deformable photodetectors,are presented.Then,the nanomaterials and organic/polymeric materials that are applicable in deformable light-emitting diodes are described.Finally,representative system-level applications of flexible and stretchable photodetectors and light-emitting diodes are reviewed,and future prospects are discussed.

Fabrication and Properties of DC Magnetron Sputtered Indium Tin Oxide on Flexible Plastic Substrate

Indium tin oxide （ITO） thin films deposited on flexible polyethylene terephthalate （PET） substrates at low temperature by DC magnetron sputtering from an In-Sn （90-10 wt pct） alloy target were studied. The correla- tion between deposition conditions and ITO property was systematically investigated and characterized. These as-deposited ITO films were used as the anode contact for flexible organic light-emitting diodes （FOLEDs）. The fabricated FOLEDs with a structure of PET/ITO/NPB （50 nm）/Alq （20 nm）/Mg：Ag （100 nm） showed a maximum luminance of 2125 cd/m^2 at 13 V.

Design and Modeling of a Flexible Conductive Fabric Antenna Integrated in an OLED Light Source for WIMAX Wireless Communication Systems

This work presents a new bendable antenna for worldwide interoperability for microwave access (WiMAX) wireless communication systems. These antennas, transparent and flexible, will be easily integrated into various mdia and in particular OLED lighting which could be part of the public lighting network of tomorrow as well as on all display media. The integration of these antennas as close as possible to the end-user is a possible solution to reduce the energy consumption which goes hand in hand with the increase in the data rate. This kind of new antenna, designed to be integrated in organic light-emitting diode (OLED), was modeled from a transparent VeilShieldTM conductive fabric and was placed on a 100% polyester substrate with a thickness of 1.5 mm and a loss tangent of 0.02. We have tested and evaluated the characteristic parameters of our antenna, namely the reflection coefficient, the radiation pattern and the gain, to find out the performance of our proposed design. The performance of the transparent conductive fabric integrated in the 100% polyester substrate is tested for the application of flexible antenna operating at 3.5 GHz with a gain value of 5.38 dB. We have integrated this proposed new antenna with the OLED light source containing four layers of different materials and electrical properties: aluminum cathode layer, polymer layer, indium tin oxide (ITO) anode layer and glass substrate layer. After integration, the resonant frequency shifted to 3.52 GHz with a gain value of 4.61 dB. In addition, we also tested the concave bending on the reflection coefficient of the proposed flexible antenna taking into account the different bending angles. This work demonstrates the possibility of integrating these unconventional materials used for the proposed antenna within the OLED despite weak effects on the resonant frequency and the gain of the proposed antenna after integration.

Thin-film organic semiconductor devices:from flexibility to ultraflexibility

Flexible thin-film organic semiconductor devices have received wide attention due to favorable properties such as light-weight,flexibility,reproducible semiconductor resources,easy tuning of functional properties via molecular tailoring,and low cost large-area solution-procession.Among them,ultraflexible electronics,usually with minimum bending radius of less than 1 mm,are essential for the development of epidermal and bio-implanted electronics,wearable electronics,collapsible and portable electronics,three dimensional(3D) surface compilable electronics,and bionics.This review firstly gives a brief introduction of development from flexible to ultraflexible organic semiconductor electronics,and design of ultraflexible devices,then summarizes the recent advances in ultraflexible thin-film organic semiconductor devices,focusing on organic field effect transistors,organic light-emitting diodes,organic solar cells and organic memory devices.

用于OLED的碳纳米管

首先,介绍了传统柔性有机发光二极管(FOLED)的基本结构及缺点。其次,对氧化铟锡(ITO)玻璃应用于FOLED生产的局限性进行了阐述。然后将碳纳米管(CNT)与ITO薄膜进行了对比,对碳纳米管应用于FOLED制备的可行性进行了分析,并对碳纳米管生产及器件的制备进行了说明。对碳纳米管的分类以及分离进行了简要阐述,着重分析了采用喷涂技术制备碳纳米管导电薄膜,并将其用作器件阳极技术以及一种较为新颖的碳纳米管阳极形式。最后,对碳纳米管的应用前景进行了展望,如碳纳米管应用于FOLED制备的关键是进行金属性碳纳米管的分离,碳纳米管对人体免疫系统的影响可能会制约碳纳米管的发展等。

基于银纳米线的柔性透明电极的制备及性能研究

有机发光二极管(organic light emitting diodes, OLEDs)可以柔性制备,在未来的可穿戴应用上有广阔的发展前景,而柔性透明电极(flexible transparent electrode, FTE)的性能直接影响着柔性OLED的性能。本文基于银纳米线(AgNWs)和聚(3,4-乙烯二氧噻吩)∶聚苯乙烯磺酸(PEDOT∶PSS)制备了FTE,并采用甲醇浸渍、氩等离子处理、紫外辐射3种不同的方式对该电极进行处理,优化FTE的光电性能。研究发现:甲醇浸渍,可减少AgNWs上聚合物的包覆;等离子体处理和紫外辐射,可对AgNWs进行焊接;而两种方式的协同作用则可以对FTE的光电性能进一步优化。实验获得最优FTE的方阻为14.18Ω/sq,在550 nm处的透过率可达到84%以上。经过500次弯曲测试后,FTE的方阻变化率低于15%。本文的工作对FTE的制备及优化提供了可行性方案。

柔性有机电致发光器件制备及光电性能研究

制作了结构为ITO/PVK:TPD/Alq3/Al、分别以PET为衬底的柔性的和以玻璃为衬底的普通的有机电致发光二极管(OLED),对两种器件的电流密度-电压曲线、光电流-电压曲线及量子效率-电流密度曲线进行了测量与分析。结果表明,它们的光电特性非常接近,但柔性OLEDs(FOLEDs)的开启电压略高;在20 V电压驱动下,FOLEDs的亮度达到1 000 cd/m2,量子效率为0.27%。对器件进行了抗弯折性能的测试。

采用碳纳米管导电薄膜作为OLED的阳极

采用碳纳米管(CNT)替代ITO作为OLED阳极可以解决ITO薄膜存在的可弯曲性能差,可靠性低等缺点,使得柔性显示成为可能。本文采用混合型CNT导电薄膜作为阳极,探讨了CNT薄膜的制备工艺、掺杂方式及表面修饰等因素对绿光OLED性能的影响。实验结果表明,P型掺杂对CNT薄膜的导电性能影响有限;而PEDOT修饰层可以很好的提高CNT导电薄膜的平整度;此外,采用"十字交叉"的阳极形状有助于降低阳极拐角处毛刺。通过优化器件各参数,制备的PET/CNTs/PEDOT/NPB/ALq3/LiF/Al绿光OLED发光效率达到了195cd/m2,结果表明采用混合型CNT作为OLED阳极是可行的。