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Featuring a combination of size-tunable emission wavelengths, high thermal stability, and low cytotoxicity, carbon quantum dots (CQDs) have opened up a new possibility for next-generation displays. However, the theoretically highest external quantum efficiency (EQE) limit of electroluminescent light-emitting diodes (LEDs) based on fluorescent CQDs is 5% due to the spin-forbidden nature of triplet state transitions. Comparatively, phosphorescent or delayed fluorescence CQDs are expected to overcome this limitation and allow the EQE of the devices to reach nearly 25%. At present, the preparation of CQDs with good solution processability, narrow bandwidth emission, and full-color phosphorescence or delayed fluorescence still faces great challenges. Herein, this review aims to offer a materials-chemistry perspective to tailor highly efficient phosphorescent or delayed fluorescence CQDs and present their applications in electroluminescent LEDs for the display technology. The mechanism and design principle of pure organic phosphorescence and delayed fluorescence as well as their recent advances in electroluminescent devices are summarized. Furthermore, we focus on the prospects and challenges for phosphorescent and delayed fluorescence CQDs in displays. We hope that this review will further stimulate the development of high-performance CQD-based electroluminescent displays with a combined effort from different disciplines.

MXenes (Ti3C2TX) are two-dimensional transition-metal carbides and carbonitrides with high conductivity and optical transparency. However, transparent MXene electrodes with high environmental stability suitable for various flexible organic electronic devices have rarely been demonstrated. By laminating a thin polymer film onto a solution-processed MXene layer to protect the MXene film from harsh environmental conditions, we present transparent and flexible MXene electronic devices. A thin polymer layer spin-coated onto a transparent MXene electrode provides environmental stability even under air exposure longer than 7 d at high temperatures (up to 70 °C) and humidity levels (up to 50%) without degrading the transparency of the electrode. The resulting polymer-laminated (PL) MXene electrode facilitates the development of a variety of field-driven photoelectronic devices by exploiting the electric field exerted between the MXene layer and the counter electrode through the insulating polymer. Field-induced electroluminescent displays, based on both organic and inorganic phosphors, with PL-MXene electrodes are demonstrated with high transparency and mechanical flexibility. Furthermore, our PL-MXene electrode exhibits high versatility through successful implementation in capacitive-type pressure sensors and triboelectric nanogenerators, resulting in field-driven sensing and energy harvesting electronic devices with excellent operation reliability.

The visualization of accurate colour information using quantum dots has been explored for decades, and commercial products employing environmentally friendly materials are currently available as backlights1. However, next-generation electroluminescent displays based on quantum dots require the development of an efficient and stable cadmium-free blue-light-emitting device, which has remained a challenge because of the inferior photophysical properties of blue-light-emitting materials2,3. Here we present the synthesis of ZnSe-based blue-light-emitting quantum dots with a quantum yield of unity. We found that hydrofluoric acid and zinc chloride additives are effective at enhancing luminescence efficiency by eliminating stacking faults in the ZnSe crystalline structure. In addition, chloride passivation through liquid or solid ligand exchange leads to slow radiative recombination, high thermal stability and efficient charge-transport properties. We constructed double quantum dot emitting layers with gradient chloride content in a light-emitting diode to facilitate hole transport, and the resulting device showed an efficiency at the theoretical limit, high brightness and long operational lifetime. We anticipate that our efficient and stable blue quantum dot light-emitting devices can facilitate the development of electroluminescent full-colour displays using quantum dots. Cadmium-free blue quantum dot light-emitting diodes are constructed with a quantum yield of unity, an efficiency at the theoretical limit, high brightness and long operational lifetime.

A stretchable alternating current electroluminescent display seamlessly combines the light-emitting capabilities with mechanical compliance, which offers exciting opportunities for applications in wearable gadgets, soft robots, and fashion designs. The widespread adaption to deformable forms of optoelectronics is currently impeded by the tedious and labor-intensive fabrication process. This study reports an efficient and scalable procedure to create a fully screen-printed, multicolor, and stretchable electroluminescent display. The as-prepared device exhibits excellent deformability and low-voltage operation. The practical implementation is demonstrated by creating a wearable sound-synchronized sensing system with an epidermal display responsive to the rhythm of music. The ink formulation and printing procedure developed here pave the way for convenient fabrication of stretchable electronic devices.

The patterning of silver nanowires (AgNWs) is subject to critical challenges, which have seriously limited their practical applications. This work describes a simple and efficient method combining screen printing with vacuum filtration for patterning AgNW networks. The screen-printed poly(dimethylsiloxane) (PDMS) mask layer was shown to be strongly adhered to the filtration membrane, which resulted in well-defined sharp edges of the deposited AgNW patterns, and a 50 μm patterning resolution was achieved. The patterned films with low densities of AgNWs (≤15 μg/cm2) were transferred to the surface of PDMS to make patterned stretchable transparent conductive films (TCFs). The low sheet resistance of 7.3 Ω/sq was achieved at an optical transmittance of 79.6% (at 550 nm wavelength) with a AgNW deposition density of only 12.5 μg/cm2. As an application example, the patterned TCFs were used as the top electrodes to fabricate stretchable alternating current electroluminescent (ACEL) displays with stretchability up to 70% of their original dimension, which were applied to a smart system for simulating heart beats together with a digitally operated flexible circuit. The ACEL device exhibited a bright and uniform emission with a clear and smooth edge even with a pattern width as narrow as 100 μm, as well as exceptional elasticity and durability in spite of bending, stretching, and twisting. The present work provides a new way of patterning AgNWs and can be extended to a variety of applications.

Stretchable alternating current electroluminescent display is an emerging form of light-emitting device by combining elasticity with optoelectronic properties. The practical implementations are currently impeded by the high operating voltages required to achieve sufficient brightness. In this study, we report the development of dielectric nanocomposites by filling surface-modified ceramic nanoparticles into polar elastomers, which exhibit a series of desirable attributes, in terms of high permittivity, mechanical deformability, and solution processability. Dielectric nanocomposite effectively concentrates electric fields onto phosphor to enable low-voltage operation of stretchable electroluminescent display, thereby alleviating safety concerns toward wearable applications. The practical feasibility is demonstrated by an epidermal stopwatch that allows intimate integration with the human body. The high-permittivity nanocomposites reported here represent an attractive building block for stretchable electron...

Lanthanide fluoride thin films have gained interest as materials for various optical applications, including electroluminescent displays and mid-IR lasers. However, the number of atomic layer deposition (ALD) processes for lanthanide fluorides has remained low. In this work, we present an ALD process for TbF3 using tris(2,2,6,6-tetramethyl-3,5-heptanedionato)terbium and TiF4 as precursors. The films were grown at 175–350 °C. The process yields weakly crystalline films at the lowest deposition temperature, whereas strongly crystalline, orthorhombic TbF3 films are obtained at higher temperatures. The films deposited at 275–350 °C are exceptionally pure, with low contents of C, O, and H, and the content of titanium is below the detection limit (

Next-generation electroluminescent displays require efficient and stable red, green and blue light-emitting diodes (LEDs) with low cost, excellent color purity and flexibility, for which perovskite-based LEDs (PeLEDs) are a promising candidate. Among the three primary colors, the low efficiencies and poor stability of blue PeLEDs is the major hurdle to their commercialization. Here, we report an in situ surface engineering strategy incorporating a simple hot injection method with one pot synthesis for surface passivation of cadmium ions (Cd2+) into blue-emissive all-inorganic perovskite nanocrystals (PNCs). The optimized PNCs containing 0.2% Cd show improved photoluminescence quantum yield (PLQY; 66.8%) and ambient stability compared to the neat PNCs (25.5%) at an emission wavelength of 475 nm. PeLEDs with the PNCs show a luminance of 51 cd m−2 and EQE of 3.71%. Through a series of ab initio calculations and comprehensive XPS analysis, we show that Cd incorporation into systems with reduced dimensionality such as PNCs likely takes place via surface inclusion in the perovskite B-site, which effectively suppresses the formation of halide defects and yields enhanced device efficiencies.

Development of a human-interactive display enabling the simultaneous sensing, visualisation, and memorisation of a magnetic field remains a challenge. Here we report a skin-patchable magneto-interactive electroluminescent display, which is capable of sensing, visualising, and storing magnetic field information, thereby enabling 3D motion tracking. A magnetic field-dependent conductive gate is employed in an alternating current electroluminescent display, which is used to produce non-volatile and rewritable magnetic field-dependent display. By constructing mechanically flexible arrays of magneto-interactive displays, a spin-patchable and pixelated platform is realised. The magnetic field varying along the z-axis enables the 3D motion tracking (monitoring and memorisation) on 2D pixelated display. This 3D motion tracking display is successfully used as a non-destructive surgery-path guiding, wherein a pathway for a surgical robotic arm with a magnetic probe is visualised and recorded on a display patched on the abdominal skin of a rat, thereby helping the robotic arm to find an optimal pathway., Designing human-interactive displays enabling the simultaneous sensing, visualization, and memorization of a magnetic field remains a challenge. Here, the authors present a skin-patchable magneto-interactive electroluminescent display by employing a magnetic field-dependent conductive gate, thereby enabling 3D motion tracking.

The authors reported a facile, scalable, high-yield, universal fabrication approach for creating micro- and nanoscale metallic patterns for flexible electronic and plasmonic applications through imprint-transfer of catalytic Pd nanoparticles using a reusable imprint mold with selectively adsorbed catalytic nanoparticles and selective electroless deposition of metals. Metallic patterns are mass-produced on flexible plastics according to the predefined micro-/nanofeatures on the imprint mold without any chemical modification on the substrate, which significantly reduces both fabrication costs and environmental pollution, compared to other methods utilizing electroless deposition. The excellent dimensional scalability and material versatility of this method have been confirmed by fabricating metallic micromeshes with a linewidth down to 3 μm, and metallic nanodisk arrays with a pitch of 500 nm. Using this method, flexible transparent electrodes were constructed on Cu micromesh-patterned plastic films with transmittance values higher than 75% and sheet resistance values below 0.4 Ohms sq−1, as well as high figures of merit up to 4 × 103. This method is further demonstrated in the fabrication of flexible thin-film heaters, electroluminescent displays, and flexible printed circuits, as well as plasmonic refractometric sensors.

The metal pattern plays a crucial role in various optoelectronic devices. However, fabrication of high-resolution metal patterns has serious problems including complicated techniques and high cost. Herein, an inkjet printed water-soluble sacrificial layer was proposed to fabricate a high-resolution metal pattern. The water-soluble sacrificial layer was inkjet printed on a polyethylene glycol terephthalate (PET) surface, and then the printed surface was deposited with a metal layer by evaporating deposition. When the deposited surface was rinsed by water, the metal layer deposited on the water-soluble sacrificial layer could be removed. Various high-resolution metal patterns were prepared, which could be used in electroluminescent displays, strain sensors, and 3D switches. This facile method could be a promising approach for fabricating high-resolution metal patterns.

All-inorganic CsPbBr3 perovskite quantum dots (QDs) hold great promise as candidate materials for next-generation electroluminescent displays owing to their excellent optoelectronic properties. However, the long insulating ligands on the surface of CsPbBr3 QDs originating from the synthesis process hinder the fabrication of high-performance optoelectronic devices. Herein, an efficient ligand-exchange route is proposed with the use of perovskite-precursor-based halide ligands, including a series of phenalkylammonium bromides with a π-conjugation benzene ring and different branch lengths. Based on the ligand-exchange method, the conductivity of the CsPbBr3 QD layer is significantly improved owing to ligand shortening and the insertion of the π-conjugation benzene ring. As a result, high brightness (up to 12,650 cd/m2) and low turn-on voltage (as low as 2.66 V) can be realized in CsPbBr3 QD light-emitting diodes (QLEDs), leading to dramatic improvements in device performance with a current efficiency of 13.43 cd/A, power efficiency of 12.05 lm/W, and external quantum efficiency of 4.33%.

Transparent conducting metal oxides (TCOs) associate the properties of high optical transparency and electrical conductivity, which makes them suitable for variety of applications such as window layer in liquid crystal and electroluminescent display devices as well as in solar cells. Among different TCO’s, cadmium oxide (CdO) has received tremendous attention as a potential alternative to Sn-doped In2O3 (ITO) due to its high intrinsic dopability coupled with outstanding mobility and high electrical conductivity. In the present study, for first time the doping of ytterbium (Yb) into CdO films prepared using a simple and effective spray pyrolysis technique demonstrated. The structural, morphological and optoelectronic properties of Yb doped CdO thin films as a function of Yb concentration (1–3 at.%) have been studied. X-ray diffraction, field-emission scanning electron microscopy, X-ray photoelectron spectroscopy, optical absorption spectroscopy, luminescence measurements and for electrical properties Hall effect set up in van der Pauw configuration have been employed to study the properties of Yb-doped CdO thin films. Yb doped CdO thin films exhibit excellent optical transparency, with an average transmittance over 75% in the visible region. It is found that Yb doping widens the optical band gap from 2.63 to 2.88 eV, via a Moss–Burstein shift and further decreases to 2.77 eV. The maximum reflectivity of 97.24% achieved for 2.5 at.% Yb:CdO film. The better values of resistivity, carrier concentration, mobility and figure of merit have been obtained for 2.5 at.% Yb:CdO, which are 2.6 × 10−4 Ω cm, 13.9 × 1020 cm−3, 17.39 cm2/Vs and 45.87 × 10−3 (Ω)−1 respectively. The obtained results revealed that Yb dopant has a significant influence on the optoelectronic properties of CdO-based TCO compound.

In the preceding decade, the metal complexes of lanthanide ions with light harvesting organic chromophores have garnered intensive and greater attention due to their marvelous performance in various advanced fields. Researches in the field of organic compounds that sensitize the luminescence phenomenon in lanthanides enforce the advancement in the preparation of novel lanthanide compounds. Better emission properties, fine color gamut and high luminescent efficiency of lanthanide complexes makes them a suitable material for electroluminescent display devices and solid state lighting. Such complexes are extensively used to manufacture optoelectronic gadgets which show occasions to conquer energy-pertinent issues. In this review, molecular structure and spectroscopic characteristic data of lanthanide complexes as an emanating layer in organic light-emitting diodes (OLEDs) have been represented systematically. The design principles, methods of device fabrication and various characterization techniques for OLEDs are described. Electroluminescent devices based on the lanthanide complexes have gathered much awareness and possess various applications in efficient energy displays, solid-state lighting and the automotive sector. The immense review on OLEDs presumes that our current lighting network can be supplanted with OLEDs, an energy saving lighting innovation.

The development of methods and means of testing the applicability of thin-film electroluminescent indicator devices as displays in aircraft is carried out. Thin-film electroluminescent displays are used in equipment and systems that require high image quality and reliability, as well as a long service life of the devices. The result of the performed work is the ExpAT program, which allows to carry out a computational experiment to test of the applicability of the TFEL indicator devices in aeronautical engineering. As a result of the computational experiment, variants of structures of thin-film emitting structures that meet the operating conditions of indicators in avionics are shown.

All inorganic CsPbBr3 perovskite quantum dots (QDs) are potential emitters for electroluminescent display. We demonstrated an easy hot-injection method to partially replace the toxic Pb2+ with the highly stable Sn4+. Meanwhile, the absolute photoluminescence (PL) quantum yield of CsPb1-xSnxBr3 with Sn(IV) substitution increased from 45% to 83%. Based on femtosecond transient-absorption (TA), time-resolved PL, and single-dot spectroscopies, TA dynamics in undoped CsPbBr3 and CsPb0.67Sn0.33Br3 QDs at various excitation fluences., providing a clear evidence for the suppression of trion generation. These highly luminescent CsPb0.67Sn0.33Br3 QDs exhibit emission wavelength of 517 nm. The highest device performance exhibited a luminescence of 12,500 cd/m2, a current efficiency (CE) of 11.63 cd/A, an external quantum efficiency (EQE) of 4.13%, a power efficiency (PE) of 6.76 lm/w, and a low turn-on voltage of 3.6 V, which are the highest values among reported Sn-based perovskite QLEDs.

All inorganic CsPbBr3 perovskite quantum dots (QDs) are potential emitters for electroluminescent displays. We have developed a facile hot-injection method to partially replace the toxic Pb2+ with highly stable Sn4+ . Meanwhile, the absolute photoluminescence quantum yield of CsPb1-x Snx Br3 increased from 45 % to 83 % with SnIV substitution. The transient absorption (TA) exciton dynamics in undoped CsPbBr3 and CsPb0.67 Sn0.33 Br3 QDs at various excitation fluences were determined by femtosecond transient absorption, time-resolved photoluminescence, and single-dot spectroscopy, providing clear evidence for the suppression of trion generation by Sn doping. These highly luminescent CsPb0.67 Sn0.33 Br3 QDs emit at 517 nm. A device based on these QDs exhibited a luminance of 12 500 cd m-2 , a current efficiency of 11.63 cd A-1 , an external quantum efficiency of 4.13 %, a power efficiency of 6.76 lm w-1 , and a low turn-on voltage of 3.6 V, which are the best values among reported tin-based perovskite quantum-dot LEDs.

This chapter gives the reader an insight into the phenomenon of luminescence, the emission kinetics, its intrinsic and extrinsic variations, features of sensitized luminescence, and self-quenching. The merits of photoluminescence as an optical analytical tool are discussed. The industrial display scenario is laid down, with special mention on thin-film electroluminescent displays and its unique features. The shift in the research focus from sulfide-based phosphors to oxide-based light emitters is briefly outlined. Various binary and ternary oxide-based phosphor system matrices are presented in detail. The chapter concludes by highlighting the significant achievements made in related works carried at our laboratory.

International audience; Magnesium yttrium oxide (MgO-Y2O3) nanocomposites have been purposefully tailored using an oxalate precursor pathway. Commonly, MgO-Y2O3 nanocomposites possessed a significant technological challenge in electroceramics; particularly remarkable as the anode material for solid oxide fuel cells (SOFC). In this regard, different weight ratios, % of MgO and Y2O3 including (20:80), (50:50) and (80:20) were fabricated based on oxalic acid as a fuel in acidic medium. Indeed, the impact of the annealing temperature on the phase composition, crystallite size, morphology and optical properties was investigated using X-ray diffraction, field emission electron microscope (FESEM), TEM, FTIR and UV-VIS-NIR spectrophotometer. The FESEM results showed the nanocomposite had a cubic like structure with the fine grain sizes of 0-150 nm because of the rapid solidification. The band gap energy was found to be 4.83, 5.10 and 5.08 eV with increasing the ratio of Mg2+ ion from 20 to 50 and 80, respectively. Eventually, our currently studies consider to be an important achievement to investigate and recognize the features of the MgO-Y2O3 system for different applications involving microwave systems, advanced displays (field emission display, plasma display, electroluminescent display), ultra-fast sensors, durable, infrared windows and lasers.

Stretchable polymer composites are a new group of materials with a wide range of application possibilities in wearable electronics. The purpose of this study was to fabricate stretchable electroluminescent (EL) structures using developed polymer compositions, based on multiple different nanomaterials: luminophore nanopowders, dielectric, carbon nanotubes, and conductive platelets. The multi-layered EL structures have been printed directly on textiles using screen printing technology. During research, the appropriate rheological properties of the developed composite pastes, and their suitability for printed electronics, have been confirmed. The structure that has been created from the developed materials has been tested in terms of its mechanical strength and resistance to washing or ironing.

Alternating Current Electroluminescence (ACEL)was measured in orange and blue phosphors and a mixture of them in a ratio of 2: 1. The phosphor, dielectric and top silver electrodes were prepared by screen printing. Nowadays ACEL is presented on the market as the only technique for quick and easy preparation of large area, low cost electroluminescent panels by the means of material printing. From the optical microscope images, we could conclude that the radiation of blue phosphor dominates over the orange one. These results are confirmed in the absolute irradiance spectra. Moreover, using samples, based on phosphor stripes leads to a decrease of the total irradiance, but, on the other hand, the uniformity of the emitted EL light is improved. Printing of striped active layer is preferred from the point of view of achieving more uniformly distributed light. The summarized fitting parameters show that driving frequency around 300 Hz will produce white light with reasonable intensity and with values of x, y coordinates higher than 0.31. The somewhat lower intensity of the emitted light can be improved by setting higher driving AC voltage. The voltage tested in this work was set to be constant at 250 V pp .

Stretchable alternating-current electroluminescent (ACEL) devices are required due to their potential in wearable, biomedical, e-skin, robotic, lighting, and display applications; however, one of the main hurdles is to achieve uniform electroluminescence with an optimal combination of transparency, conductivity, and stretchability in electrodes. We therefore propose a fabrication scheme involving strategically combining two-dimensional graphene layers with a silver nanowire (Ag NW)-embedded PEDOT:PSS film. The developed hybrid electrode overcomes the limitations of commonly known metallic NWs and ionic conductor-based electrodes for ACEL applications. Furthermore, the potential of the hybrid electrode is realized in demonstrating large-area stretchable ACEL devices composed of an 8 × 8 passive array. The prototype ACEL passive array demonstrates efficient and uniform electroluminescence under high levels of mechanical deformation such as bending, rolling, twisting, and stretching.

Today, Quantum Dots are perfecting LCD displays, enabling a new generation of brighter, more efficient televisions with lifelike colors. This has given LCD technology an important edge as it battles new display entrants such as WOLED. What’s next for this novel nanotechnology? This paper looks at how quantum dots are the technology platform for displays including their evolving use in LCD displays, as well as how they enhance and are being used in OLEDs and micro-LED displays, and how they are being developed as emitter materials for future printable electroluminescent displays.

Colloidal semiconductor nanocrystals (SCNCs) or, more broadly, colloidal quantum nanostructures constitute outstanding model systems for investigating size and dimensionality effects. Their nanoscale dimensions lead to quantum confinement effects that enable tuning of their optical and electronic properties. Thus, emission color control with narrow photoluminescence spectra, wide absorbance spectra, and outstanding photostability, combined with their chemical processability through control of their surface chemistry leads to the emergence of SCNCs as outstanding materials for present and next-generation displays. In this Review, we present the fundamental chemical and physical properties of SCNCs, followed by a description of the advantages of different colloidal quantum nanostructures for display applications. The open challenges with respect to their optical activity are addressed. Both photoluminescent and electroluminescent display scenarios utilizing SCNCs are described., Comment: 59 pages, 13 figures

Solid ternary compounds of Eu(III) with fluorinated β-diketone (4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)-1,3-hexanedione) (Hfth) and heteroaromatic monodentate ancillary ligands (aqua/triphenylphosphineoxide/pyridine-N-oxide/2-pyridionl-N-Oxide) were prepared for red color emissive materials. The luminescence characteristics of prepared compounds were illustrated using absorption and emission spectral measurements which specified that the β-diketone ligand could effectively sensitized the central europium ion meant for the improved emission of the light. Due to interaction metal complexes displays distinguished effectual on photoluminescence efficacy (η) as well as Judd Ofelt luminous factor (Ω2). An extensive relative approach of enhancement in luminescent behavior of the synthesized metal complexes had been carried out by replacing aqua ligand in the inner coordination sphere of conventionally prepared parent aqua complex with others ancillary oxide ligands to make metal complex co-coordinatively saturated as well as suitable for fabricating electroluminescent display devices.

The colour purity and high photoluminescence quantum efficiency of quantum dots has led to their widespread use in the backlight units of liquid crystal displays. However, as industry standards continue to push the boundaries of display technology, new technologies are needed to meet these requirements. Herein, we discuss the development of heavy metal-free quantum dots for use in next-generation electroluminescent displays.

Electroluminescence (EL) of commercial phosphor pastes was investigated and an equivalent circuit of the EL stack was determined. The model was used to develop a simple driver electronics capable to operate electroluminescent displays (ELD) with a good contrast and visibility. Flexible displays with a passive matrix of 32 × 5 pixels and up to 11 pictogram elements were produced by screen printing on PET foil and combined with the driver to form a standalone unit. Several demonstrators with the ELDs integrated into a bag or a back pack were manufactured with the primary goal to allow traffic signalling for cyclists or skaters during the dark periods of day; the displays were controlled wirelessly using either a smartphone or a dedicated control device. Present work describes technical implementation details of the printed electroluminescent display and its driving electronics. The following aspects are discussed: empirical model of the EL stack, intensity of emitted light in dependence of driving voltage and frequency, waveforms used for driving the ELD, implemented driver circuit, layout and packaging considerations for the display module.

Organic electronics are the domain in which the components and circuits are made of organic materials. This new electronics help to realize electronic and optoelectronic devices on flexible substrates. In recent years, organic materials have replaced conventional semiconductors in many electronic components such as, organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs) and organic photovoltaic (OPVs). It is well known that organic light emitting diodes (OLEDs) have many advantages in comparison with inorganic light-emitting diodes LEDs. These advantages include the low price of manufacturing, large area of electroluminescent display, uniform emission and lower the requirement for power. The aim of this paper is to model polymer LEDs and OLEDs made with small molecules for studying the electrical and optical characteristics. The purpose of this modeling process is, to obtain information about the running of OLEDs, as well as, the injection and charge transport mechanisms. The first simulation structure used in this paper is a mono layer device; typically consisting of the poly (2-methoxy-5(2`-ethyl) hexoxy-phenylenevinylene) (MEH-PPV) polymer sandwiched between an anode with a high work function, usually an indium tin oxide (ITO) substrate, and a cathode with a relatively low work function, such as Al. Electrons will then be injected from the cathode and recombine with electron holes injected from the anode, emitting light. In the second structure, we replaced MEH-PPV by tris (8-hydroxyquinolinato) aluminum (Alq3). This simulation uses, the Poole-Frenkel -like mobility model and the Langevin bimolecular recombination model as the transport and recombination mechanism. These models are enabled in ATLAS- SILVACO. To optimize OLED performance, we propose to change some parameters in this device, such as doping concentration, thickness and electrode materials.

Lanthanide complexes are widely used as emitters for applications in the fields of bioimaging, molecular sensing, disease diagnosis, and optoelectronics. Particularly, the high luminescence efficiencies of these complexes make them attractive for electroluminescent display and solid-state lighting. As color purity and saturation are the most stringent criteria for red emission in display technology, europium(III) complexes featuring an emission peak centered at ∼612 nm with a narrow bandwidth hold great potential as red-emitting materials. This review highlights the recent development of electroluminescent europium(III) complexes, with emphasis on correlations between molecular structures and optoelectronic performance. After a fundamental introduction on the optical and electrical properties of europium(III) complexes, efforts will be devoted toward the controlled synthesis and functionalization of molecules for improved charge injection/transportation, good processability, and enhanced emission efficiency.

A screen-printed electroluminescent display with different sensing capabilities is presented. The sensing principle is based on the direct relationship between the light intensity of the lamp and the conductivity of the external layers. The proposed device is able to detect the ionic concentration of any conductive species. Using both top and bottom emission architectures, for the first time, a humidity sensor based on electroluminescent display functionalized by a graphene oxide nanocomposite is introduced. In this regard, just by coupling the display to a smartphone camera sensor, its potential was expanded for automatically monitoring human respiration in real time. Besides, the research includes a responsive display in which the light is spatially turned on in response to pencil drawing or any other conductive media. The above mentioned features together with the easiness of manufacturing and cost-effectiveness of this electroluminescent display can open up great opportunities to exploit it in sensing applications and point-of-care diagnosis., We acknowledge financial support from EU Graphene Flagship Core 2 Project (No. 785219). This work is also funded by the CERCA Program/Generalitat de Catalunya. ICN2 is supported by the Severo Ochoa program from the Spanish MINECO (Grant No. SEV-2013-0295). A.Y. and O.C. thank the Science Achievement Scholarship of Thailand (SAST), the Thailand Research Fund via the Research Team Promotion Grant (RTA6080002) and the Ratchadaphisaksomphot Endowment Fund of Chulalongkorn University. A.M. thanks Silver Merkoci̧ from Gwent Electronic Materials Ltd./Sun Chemical for his inspiring discussions on the use of electroluminescent materials in sensing. R.Á.-D. acknowledges the financial support from the CONACYT (Mexico).

A novel geometry for electroluminescent devices, which does not require transparent electrodes for electrical input, is demonstrated, theoretically analyzed, and experimentally characterized. Instead of emitting light through a conventional electrode, light emission occurs through a polar liquid or solid and input electrical electrodes are coplanar, rather than stacked in a sandwich configuration. This new device concept is scalable and easily deployed for a range of modular alternating-current-powered electroluminescent light sources and light-emitting sensing devices. The polar-electrode-bridged electroluminescent displays can be used as remotely readable, spatially responsive sensors that emit light in response to the accumulation and distribution of materials on the device surface. Using this device structure, various types of alternating current devices are demonstrated. These include an umbrella that automatically lights up when it rains, a display that emits light from regions touched by human fingers (or painted upon using a mixture of oil and water), and a sensor that lights up differently in different areas to indicate the presence of water and its freezing. This study extends the dual-stack, coplanar-electrode device geometry to provide displays that emit light from a figure drawn on an electroluminescent panel using a graphite pencil.

We investigated blue fluorescent organic light-emitting diode (OLED) with a charge control layer (CCL) to produce high efficiency and improve the half-decay lifetime. Three types of devices (device A, B, and C) were fabricated following the number of CCLs within the emitting layer (EML), maintaining the thickness of whole EML. The CCL and host material, 2-methyl-9,10-di(2-naphthyl)anthracene, which has a bipolar property, was able to control the carrier movement with ease inside the EML. Device B demonstrated a maximum luminous efficiency (LE) and external quantum efficiency (EQE) of 9.19 cd/A and 5.78%, respectively. It also showed that the enhancement of the half-decay lifetime, measured at an initial luminance of 1,000 cd/m2, was 1.5 times longer than that of the conventional structure. A hybrid white OLED (WOLED) was also fabricated using a phosphorescent red emitter, bis(2-phenylquinoline)-acetylacetonate iridium III doped in 4,4'-N,N'-dicarbazolyl-biphenyl. The property of the hybrid WOLED with CCL showed a maximum LE and an EQE of 13.46 cd/A and 8.32%, respectively. It also showed white emission with Commission International de L'Éclairage coordinates of (x = 0.41, y = 0.33) at 10 V.

Optoelectronic materials can source, detect, and control light wavelengths ranging from gamma and x rays to ultraviolet, visible, and infrared regions. Optoelectronic devices are usually systems that transduce electricity to optical signal or vice versa. Optoelectronic devices include many modern necessities such as lamps, displays, lasers, solar cells, and various photodetectors. Some important research topics in the field of optoelectronics materials are development of new materials, new technologies for fabricating materials, and design of device structures. Atomic layer deposition (ALD) is a technology that was developed in the early 1970s for manufacturing high-quality luminescent and dielectric films to be used in AC-driven thin film electroluminescent (TFEL) displays. Monochromic yellow-black displays based on a ZnS:Mn luminescent layer have been manufactured industrially using ALD since the mid-1980s. Multicolor displays (green-yellow-red) were successfully realized by filtering the broad emission band of ZnS:Mn or adding another luminescent material, e.g., green-emitting ZnS:Tb or SrS:Ce. However, applicable full-color AC TFEL devices could not be developed because of the lack of an efficient deep blue-emitting phosphor. Currently, the most promising application area in TFEL displays is transparent displays, which are commonly used in various vehicles. In the mid-1980s, epitaxial III-V semiconductors were studied using ALD. It was shown that manufacturing real epitaxial [atomic layer epitaxy (ALE)] films is possible for different III (Al, Ga, In) and V (N, P, As) materials. The advantages of ALE processing compared to more traditional metalorganic chemical vapor deposition or molecular beam epitaxy methods have remained low, however, and ALE is not used on a large scale. Research continues to be carried out using ALE, especially with nitride films. Thin film solar cells have continuously received attention in ALD research. ALD films may be used as both an absorber (CdTe, SnS) and a passivation [In2S3, Zn(O,S)] material. However, in the solar cell field, the real industrial-level use is in passivation of silicon cells. Thin ALD Al2O3 film effectively passivates all types of silicon cells and improves their efficiency. Transition metal dichalcogenides are emerging 2D materials that have potential uses as channel materials in field-effect transistors, as well as phototransistors and other optoelectronic devices. The problem with achieving large-scale use of these 2D materials is the lack of a scalable, low-temperature process for fabricating high-quality, large-area films. ALD is proposed as a solution for these limitations. This review covers all of these ALD applications in detail.Optoelectronic materials can source, detect, and control light wavelengths ranging from gamma and x rays to ultraviolet, visible, and infrared regions. Optoelectronic devices are usually systems that transduce electricity to optical signal or vice versa. Optoelectronic devices include many modern necessities such as lamps, displays, lasers, solar cells, and various photodetectors. Some important research topics in the field of optoelectronics materials are development of new materials, new technologies for fabricating materials, and design of device structures. Atomic layer deposition (ALD) is a technology that was developed in the early 1970s for manufacturing high-quality luminescent and dielectric films to be used in AC-driven thin film electroluminescent (TFEL) displays. Monochromic yellow-black displays based on a ZnS:Mn luminescent layer have been manufactured industrially using ALD since the mid-1980s. Multicolor displays (green-yellow-red) were successfully realized by filtering the broad emission...

Electroluminescent (EL) lamps are flat solid-state ac driven devices in which light is generated by impact excitation to optical energies of luminescent centers in a Mn-, Cu-, or Tb-doped ZnS phosphor layer by high-energy electrons and radiant decay to the ground state of these luminescent centers. They are useful in applications which require diffuse low-level uniform illumination. This paper presents measurements of light emission and related spectra of EL lamps as a function of operation frequency and sinusoidal voltage amplitude. The excitation of other voltage waveforms is also analyzed, and parameters of the equivalent electrical circuit are presented.

The combination of a SiO2 electron accelerator layer with a silicon-rich nitride layer forming a bilayer embedded in a metal-oxide-semiconductor structure has proved to enhance the integrated visible-infrared EL intensity by more than two orders of magnitude in comparison to the single-layer electroluminescent device approach. The origin of such an improvement is attributed to the massive ionization of defects in the silicon-rich nitride layer by direct impact of injected hot electrons coming from the SiO2 conduction band. Our premises are further corroborated by performing a thorough study of the charge transport in the bilayer structure. This study displays a main electrical mechanism at steady state that combines hot-electron tunneling injection from the SiO2 accelerator layer and space charge-limited current enhanced by Poole-Frenkel conduction from the silicon-rich nitride electroluminescent layer. The proposed electrical mechanism is validated by numerical simulations that provide good agreement with the experimental behavior. These results point out the feasibility of boosting electroluminescence efficiency of Si-based light emitting devices by performing an adequate gate stack engineering that maximizes the hot-electron injection into the electroluminescent layer.

Advances in image quality in recent decades have made it necessary to develop new technologies for producing displays to meet remarkably stricter standards. The display market is governed mainly by liquid crystal display and light-emitting diode (LED) technology; however, it suffers from limitations that can be overcome by developing the next generation of electroluminescent displays. The introduction of colloidal quantum dots (QDs) as down-converters has enabled the production of displays with extremely high color purity and gamut. Therefore, colloidal nanocrystals are excellent candidates for the preparation of electroluminescent devices, which represent a straightforward approach to the development of unprecedented high-quality displays. We synthesized light-emitting QDs covering the entire visible spectrum with high fluorescence quantum yields and color purity, and produced high-brightness single-color LEDs with external quantum efficiencies of 0.39%, 1.04%, 2.10%, and 1.30% for red-, orange-, green-, and blue-emitting dots, respectively. Additionally, white LEDs were prepared by mixing QDs; they showed color temperatures of 5,300 K and color rendering indices exceeding 80%. Very importantly, we exhaustively characterized the LED performance, including the response time, stability, and evolution of the light characteristics, thus providing crucial information toward the development of high-quality electroluminescent displays.

International audience; Recent advances in materials science research have enabled the production of highly stretchable sensors and displays. However, such technologies are not yet accessible to non-expert makers. We present a novel and inexpensive fabrication method for creating Stretchis, highly stretchable user interfaces that combine sensing capabilities and visual output. We use Polydimethylsiloxan (PDMS) as the base material for a Stretchi and show how to embed stretchable touch and proximity sensors and stretchable electroluminescent displays. Stretchis can be ultra-thin, flexible, and fully customizable, enabling non-expert makers to add interaction to elastic physical objects, shape-changing surfaces, fabrics, and the human body. We demonstrate the usefulness of our approach with three application examples that include ubiquitous computing, wearables and on-skin interaction.

In this demo we aim to demonstrate final design and hardware implementation of our large and fully flexible electroluminescent based 48 X 48 pixel display (ELD) panel. Each panel is 45 X 45 cm and they can be connected horizontally to increase overall area. EL is an enabling technology for highly flexible, robust and large-scale displays production. The display has a very simple layer structure and it can be printed manually without need for a specialized manufacturing facility. Due to the high voltage alternating field nature of an EL main complexity comes down to the driving circuitry. We also implemented a stackable, high voltage display driver circuit architecture to further ease the control and expansion of our display.

An extremely stretchable electroluminescent device is fabricated by P. S. Lee and co-workers, as described on page 4490. The stretchable alternating-current electroluminescent (ACEL) device possesses extremely high stretchability, and can be linearly stretched to 700% with the luminance being maintained at 70% of the initial value before stretching. The device can be repeatedly stretched to 400% with stable emission behavior. The presented device will provide new opportunities in stretchable lighting, volumetric 3D displays, interactive readout systems, and other unprecedented applications.

A high permittivity composite is developed to enhance the brightness of stretchable electroluminescent displays. The unique two-step assembly process yields dense layers, in which the voids around the electroluminescent particles are filled with smaller high dielectric particles. A stretchable seven-segment display based on the composite is bright enough to be used under standard indoor lighting conditions.

To make a full color organic electroluminescent display, conventionally it requires three fine metal shadow masks (FMM) to pattern the red, green and blue light-emitting layer. In this work, by arranging the blue light-emitting layer as a shared layer for all sub-pixels, we demonstrate that a full color display can be achieved by two FMM processes, thus reducing one FMM process compared to conventional method. The red, green and blue sub-pixels can be optimized independently despite the reduction of one FMM process. Also, the performance of the red and green sub-pixels is not degraded by the shared blue light-emitting layer. Due to elimination of one FMM, the process TACT time, mask cost and alignment error can all be reduced, thus cutting down the manufacturing cost of full color organic electroluminescent display.

[EN] Many types of solutions have been studied and developed in order to give the user feedback when using touchpads, buttons, or keyboards in textile industry. Their application on textiles could allow a wide range of applications in the field of medicine, sports or the automotive industry. In this work, we introduce a novel solution that combines a 2D touchpad with an electroluminescent display (ELD). This approach physically has two circuits over a flexible textile substrate using the screen-printing technique for wearable electronics applications. Screen-printing technology is widely used in the textile industry and does not require heavy investments. For the proposed solution, different layer structures are presented, considering several fabric materials and inks, to obtain the best results., This work was supported by Spanish Government/FEDER funds (grant number MAT2015-64139-C4-3-R (Mineco/Feder)). The work presented is also funded by the Conselleria d'Economia Sostenible, Sectors Productius i Treball, through IVACE (Instituto Valenciano de Competitividad Empresarial) and cofounded by ERDF funding from the EU. Application No.: IMAMCI/2017/1.

Alternating-current-type inorganic powder electroluminescence (PEL) devices were successfully fabricated on four kinds of paper substrates, i.e., glossy paper, sticker paper, magazine paper, and newspaper. To protect the paper from wet chemical and heating processes during the formation of the PEL device, the paper substrate was coated with a spin-on-glass layer that served as a buffer layer. In spite of the fragility of paper, quite satisfactory results were obtained-the performance of paper-based PEL devices was almost equivalent to that of PEL devices on a plastic substrate. Extension of a substrate to paper, even to flimsy daily newspaper, will widen the opportunity of PEL devices as one of flexible and disposable displays.