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Produced at ton scale, vat dyes are major environmental pollutants generated by the textile industry. However, they represent ideal and accessible candidates for chemical upcycling since they are usually composed of large π‐conjugated scaffolds. Based on the valorization of "old" products, waste or even contaminant into high‐added value goods, this concept can be easily transposed to the laboratories. As a contribution to the current environmental and ecological transition, we demonstrate herein the valorization/upcycling of wastewaters generated during the dyeing procedure. To do so, the reduced (leuco) form of vat violet 10, also known as isoviolanthrone, was functionalized to afford a readily soluble derivative that was subsequently and successfully used as active material in operating solution processed light‐emitting electrochemical cells, that is, from textile dyeing to high‐tech application. [ABSTRACT FROM AUTHOR]

Polymer light‐emitting electrochemical cells (PLECs) and light‐emitting diodes (PLEDs) receive interest for large‐area lighting and signage applications. During operation of a PLEC, a p–i–n junction develops where electrons and holes are injected into the film and are transported along n‐ and p‐doped regions to the intrinsic (i) region, where they recombine under light emission. Conceptually, this resembles the PLED device architecture equipped with Ohmic charge‐injection and transport layers. The similarity between the i‐region of the PLEC and the emissive layer of the PLED is obvious; however, implication of this has not been examined in detail so far. For example, for PLEDs it is known that electron traps hinder the electron transport, and that hole trap formation dictates the long‐term durability. Here, for PLECs the electrical and optical response to electrical driving and breaks are studied, the current response to external light irradiation is probed, and degradation is followed with long‐term absorption and capacitance measurements. The electron traps in PLECs are identified and it is found that hole trap formation limits the device lifetime, in the same manner as established for PLEDs. It is concluded that charge traps in semiconducting polymers present important, but so far overlooked intrinsic performance limitations for PLECs. [ABSTRACT FROM AUTHOR]

Light-emitting electrochemical cells (LECs) have received increasing attention during recent years due to their simple architecture, based on solely air-stabile materials, and ease of manufacture in ambient atmosphere, using solution-based technologies. The LEC's active layer offers semiconducting, luminescent as well as ionic functionality resulting in device physical processes fundamentally different as compared with organic light-emitting diodes. During operation, electrical double layers (EDLs) form at the electrode interfaces as a consequence of ion accumulation and electrochemical doping sets in leading to the in situ development of a light-emitting p-i-n junction. In this paper, we comment on the use of impedance spectroscopy in combination with complex nonlinear squares fitting to derive key information about the latter events in thin-film ionic transition metal complex-based light-emitting electrochemical cells based on the model compound bis-2-phenylpyridine 6-phenyl-2,2'-bipyridine iridium(III) hexafluoridophosphate ([Ir(ppy)2(pbpy)][PF6]). At operating voltages below the bandgap potential of the ionic complex used, we obtain the dielectric constant of the active layer, the conductivity of mobile ions, the transference numbers of electrons and ions, and the thickness of the EDLs, whereas the transient thickness of the p-i-n junction is determined at voltages above the bandgap potential. Most importantly, we find that charge transport is dominated by the ions when carrier injection from the electrodes is prohibited, that ion movement is limited by the presence of transverse internal interfaces and that the width of the intrinsic region constitutes almost 60% of the total active layer thickness in steady state at a low operating voltage. [ABSTRACT FROM AUTHOR]

[Display omitted] • A DFT-based theoretical approach to investigate interactions in PLECs was presented. • Electrochemical and electrodynamic processes can take place in PLECs. • Interaction between ions and neutral polymer facilitates the charge injection. • Interaction between ions and charged polymer stabilizes localized electronic levels. • Charge hopping and ions movement govern the charge transport in PLECs. Polymer light emitting electrochemical cells (PLECs) are organic electronic devices that define interesting alternatives to organic light-emitting devices. However, despite their potential application, some of the basic operational mechanisms involved in their operation are still not completely understood. In this context, here we report a theoretical attempt to unravel some basic aspects on this subject considering a model system based on poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4- phenylene vinylene] (MDMO-PPV), potassium(I) trifluoromethanesulfonate (KCF 3 SO 3) and polyethylene oxide (PEO). Structural and reactivity properties of the constituents were evaluated via DFT-based electronic structure calculations. Condensed-to-atoms Fukui indexes were estimated via Hirshfeld partition charge to identify preferred sites for PLEC component's interactions. The results suggest that the presence of ionic salt induces significant changes on the semiconducting polymer's electronic properties, which are dependent on the number of salt molecules and their oxidation state, influencing the devices' charge dynamics (injection and transport), reinforcing previous results obtained for other similar systems. [ABSTRACT FROM AUTHOR]

Abstract Great efforts have been made to develop blue emitting organic small molecules for light-emitting electrochemical cells. Herein, blue emitting CPC (CarPhenCar) was synthesized and its emissive properties were studied. CPC exhibits blue fluorescence in toluene solution as well as in solid thin-films. CPC exhibits good thermal and electrochemical stabilities. Application of CPC molecule in solution processed light-emitting electrochemical cells resulted blue emission centered at 485 nm with brightness of 454 cd/m2, current efficiencies of 1.33 cd/A and external quantum efficiencies of 1.76%. These results adequately demonstrate the practicability of tuning the emission color of phenothiazine derivative into blue region. Graphical abstract Image 1 Highlights • Charged organic small molecule was synthesized and photophysically characterized. • Synthesized compound shows blue color in solution as well as in thin-film state. • Light-emitting electrochemical cells (LECs) were fabricated. • Blue color light emission with CIE of (0.16, 0.33). [ABSTRACT FROM AUTHOR]

Abstract: The light‐emitting electrochemical cell (LEC) is fundamentally dependent on mobile ions for its operation. In polymer LECs, the mobile ions are commonly provided by dissolving a salt in an ion transporter, with the latter almost invariably being an ether‐based compound. Here, the synthesis, characterization, and application of a new class of carbonate‐based ion transporters are reported. A polymer LEC, comprising a star‐branched oligocarbonate endowed with aliphatic side groups as the ion transporter, features a current efficacy of 13.8 cd A−1 at a luminance of 1060 cd m−2, which is a record‐high efficiency/luminance combination for a singlet‐emitting LEC. It is further established that the design principles of a high‐performance carbonate ion transporter constitute the selection of an oligomeric structure over a corresponding polymeric structure and the endowment of the oligomer with functional side chains to render it compatible with the polymeric emitter. [ABSTRACT FROM AUTHOR]

Abstract: Solid‐state lighting (SSL) is one of the biggest achievements of the 20th century. It has completely changed our modern life with respect to general illumination (light‐emitting diodes), flat devices and displays (organic light‐emitting diodes), and small labeling systems (light‐emitting electrochemical cells). Nowadays, it is however mandatory to make a transition toward green, sustainable, and equally performing lighting systems. In this regard, several groups have realized that the actual SSL technologies can easily and efficiently be improved by getting inspiration from how natural systems that manipulate light have been optimized over millennia. In addition, various natural and biocompatible materials with suitable properties for lighting applications have been used to replace expensive and unsustainable components of current lighting devices. Finally, SSL has also started to revolutionize the biomedical field with the achievement of efficient implantable lighting systems. Herein, the‐state‐of‐art of (i) biological materials for lighting devices, (ii) bioinspired concepts for device designs, and (iii) implantable SSL technologies is summarized, highlighting the perspectives of these emerging fields. [ABSTRACT FROM AUTHOR]

Abstract: The use of biomaterials and bioinspired concepts in electronics will enable the fabrication of transient and disposable technologies within areas ranging from smart packaging and advertisement to healthcare applications. In this work, the use of a nonhalogenated biodegradable solid polymer electrolyte based on poly(ε‐caprolactone‐co‐trimethylene carbonate) and tetrabutylammonium bis‐oxalato borate in light‐emitting electrochemical cells (LECs) is presented. It is shown that the spin‐cast devices exhibit current efficiencies of ≈2 cd A−1 with luminance over ≈12 000 cd m−2, an order of magnitude higher than previous bio‐based LECs. By a combination of industrially relevant techniques (i.e., inkjet printing and blade coating), the fabrication of LEC devices on a cellulose‐based flexible biodegradable substrate showing lifetimes compatible with transient applications is demonstrated. The presented results have direct implications toward the industrial manufacturing of biomaterial‐based light‐emitting devices with potential use in future biodegradable/biocompatible electronics. [ABSTRACT FROM AUTHOR]

Abstract: Recently, the use of a new family of electroluminescent copper(I) complexes—i.e., the archetypal [Cu(IPr)(3‐Medpa)][PF6] complex; IPr: 1,3‐bis‐(2,6‐di‐iso‐propylphenyl)imidazole‐2‐ylidene; 3‐Medpa: 2,2′‐bis‐(3‐methylpyridyl)amine—has led to blue light‐emitting electrochemical cells (LECs) featuring luminances of 20 cd m−2, stabilities of 4 mJ, and efficiencies of 0.17 cd A−1. Herein, this study rationalizes how to enhance these figures‐of‐merit optimizing both device fabrication and design. On one hand, a comprehensive spectroscopic and electrochemical study reveals the degradation of this novel emitter in common solvents used for LEC fabrication, as well as the impact on the photoluminescence features of thin‐films. On the other hand, spectro‐electrochemical and electrochemical impedance spectroscopy assays suggest that the device performance is strongly limited by the irreversible formation of oxidized species that mainly act as carrier trappers and luminance quenchers. Based on all of the aforementioned, device optimization was realized using ionic additives and a hole transporter either as a host–guest or as a multilayered architecture approach to decouple hole/electron injection. The latter significantly enhances the LEC performance, reaching luminances of 160 cd m−2, stabilities of 32.7 mJ, and efficiencies of 1.2 cd A−1. Overall, this work highlights the need of optimizing both device fabrication and design toward highly efficient and stable LECs based on cationic copper(I) complexes. [ABSTRACT FROM AUTHOR]

This work provides the synthesis, structural characterization, electrochemical and photophysical features, as well as the application in light-emitting electrochemical cells (LECs) of a novel small molecule belonging to the pyridilimidazo[1,5-a]pyridine family, namely 3-(2-methoxyphenyl)-5-methyl-1-(6-methylpyridin-2-yl)H-imidazo[1,5-a]pyridine (Me-impy). This compound shows a low-cost and facile synthesis, excellent redox properties, and a high photoluminescence quantum yield (Φ) of 0.4 associated to a blue emission (∼436 nm) in solution. Despite these appealing features, the emission in solid state is red-shifted to the yellow region, owing to its aggregation character. Additionally, the electroluminescence response shows a broader and red-shifted emission even upon dilution of Me-impy thin films with polymethyl methacrylate (PMMA). Herein, we report an in-depth study on the aggregation features and their impact on the electroluminescence response of Me-impy, providing relevant information to design small-molecule based LECs. [ABSTRACT FROM AUTHOR]

In contrast to mononuclear iridium(III) complexes, dinuclear iridium(III) complexes have been less well studied, especially as dopants in phosphorescent organic light-emitting devices (PhOLEDs). This is largely a consequence of the established view that dinuclear iridium(III) complexes are poorly emissive and give unsatisfactory device performance. However, this is not always the case. In this review, recent advances in dinuclear iridium(III) complexes and their applications in OLEDs are discussed. Systems with bridges comprising bis(µ-Cl), bis(µ-NCO), N^N, N^O and C^N structures are included. The relationships between chemical structures and luminescent properties are presented. Additionally, recent reports of good electroluminescence (EL) performance of dinuclear iridium(III) emitters demonstrate that rationally designed diiridium complexes present a feasible alternative to typical monoiridium systems in optoelectronic applications, with the bridging ligands providing additional structural versatility. [ABSTRACT FROM AUTHOR]

In this minireview, a state of the art of the NHC transition metal complexes applied in two different modern technologies for lightening applications, namely Organic Light Emitting Diodes (OLEDs) and Light-Emitting Electrochemical Cells (LECs), is presented. In each technology, the different transition metal centres studied are described and the advantages brought by the NHC ligands in terms of electronic and steric properties is discussed. Devices obtained with these complexes are also presented and the stability and their efficiencies are also highlighted. [ABSTRACT FROM AUTHOR]

Solid-state light-emitting electrochemical cells (LECs) show several advantages over conventional organic light-emitting devices (OLEDs) such as simple device structure compatible with solution processes, low operation voltage and capability of utilizing inert cathode metals. However, device performance of LECs must be improved, e.g. enhancing light extraction, to meet the requirements for practical applications. Among the optical modes trapped in LECs, light trapped in substrate mode is easier to be extracted, e.g. , by simply roughing the output surface. Therefore, increasing the percentage of substrate mode is beneficial in improving light extraction. In this work, the contributions of optical modes in LECs employing substrates with various refractive indices are analyzed. Higher-refractive-index substrates are shown to trap more light in the substrates. Smaller refractive index difference between higher-refractive-index substrate and indium tin oxide (ITO) layer also increases the cutoff spectral range of light waveguided in ITO layer. Furthermore, light intensity in surface plasmon mode significantly reduces as the refractive index of the substrate increases. Reducing the percentage of surface plasmon mode facilitates light extraction since it requires more complicated methods for outcoupling light in this mode. With commercially available unpolished sapphire substrates, light output of LECs is enhanced by 56%. When a scattering layer was inserted between ITO and sapphire substrate, more light in substrate mode can be extracted and 71% enhancement in light output is realized. High external quantum efficiency up to 5.5% is consequently obtained in LECs based on a ruthenium complex. Such device efficiency is among the highest reported values for red-emitting LECs and thus confirms that utilizing higher-refractive-index substrates would offer a simple and feasible approach to improve light output of LECs. In comparison to OLEDs, increased EL trapped in substrates of LECs mainly comes from surface plasmon mode rather than waveguide mode. [ABSTRACT FROM AUTHOR]

In consideration of the advantages of light-emitting electrochemical cells (LECs), it is desired to develop the saturated blue LECs for LEC display, which is hindered by the features of broad emission spectrum and emission peak not short enough. In this study, we demonstrated a novel method to improve blue saturation of the sky-blue LECs by engineering its emission spectrum through the plasmonic filters. These plasmonic filters composed of randomly distributed silver nanoparticles (Ag-NPs) can absorb the green and red emission tail of the sky-blue LECs due to localized surface plasmon resonance (LSPR). The LSPR wavelengths of Ag-NPs are tuned by manipulating the effective refractive index of materials around Ag-NPs through the accurate control of the TiO 2 thickness using atomic layer deposition technique. By integrating with the plasmonic filters, the CIE1931 coordinate of the blue LECs can approach to (0.14, 0.22), which is comparable to or even better than the reported bluest values of blue LECs. Combination with the green and red LECs, the color gamut increases from 34% (without filters) to 54% of National Television System Committee (NTSC) color gamut, corresponding to 1.6 times enhancement. In addition, the blue LECs integrated with plasmonic filters still have better efficiency than those of the reported bluest LECs. [ABSTRACT FROM AUTHOR]

The authors present high-color-rendering-index (CRI) white polymer light-emitting electrochemical cells (PLECs) based on ionic host-guest systems. PLECs were fabricated with blend films composed of a blue fluorescent cationic π-conjugated polymer, poly(9,9-bis[6′-( N , N , N ,-trimethylammonium)hexyl]fluorine- co -alt-1,4-phenylene)bromide (PFN + Br − ), used as a host, and a red phosphorescent cationic iridium complex, [Ir(ppy) 2 (biq)] + (PF 6 ) − (where (ppy) − = 2-phenylpyridinate and biq = 2,2′-biquinoline), used as a guest. By optimizing the composition of PFN + Br − and [Ir(ppy) 2 (biq)] + (PF 6 ) − in the active layers, white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (x = 0.28, y = 0.31) and a very high CRI of 95.8 was achieved through mixing of blue and red light at an applied voltage of 4.0 V. The white light emissions were obtained at a low [Ir(ppy) 2 (biq)] + (PF 6 ) − concentration (PFN + Br − :[Ir(ppy) 2 (biq)] + (PF 6 ) − = 1:0.01 (mass ratio)), showing that [Ir(ppy) 2 (biq)] + (PF 6 ) − acts as a suitable energy acceptor. The emission mechanism of the ionic host-guest PLECs can be explained by Förster resonance energy transfer (FRET) and Dexter energy transfer (DET) from the excited PFN + Br − to [Ir(ppy) 2 (biq)] + (PF 6 ) − . Utilization of ionic host-guest PLECs is a very promising method for realizing white light-emitting devices with very high CRI. [ABSTRACT FROM AUTHOR]

Abstract: Quantum dot/electrolyte hybrid light‐emitting devices (QLECs) present a novel class of large‐area light‐emitting devices potentially combining the efficiency, robustness, and color‐tunability of colloidal quantum dots (QDs) with the simple device architecture and easy fabrication of light emitting electrochemical cells. In this work, a Cd‐free QLEC based on CuInS2/ZnS (CIS/ZnS) core/shell QDs is presented. The impact of the amount of ionic liquid on the QLEC device performance is systematically studied. The introduction of the additional electron injecting/hole blocking ZnO nanocrystal top layer as well as the proper adjustment of the ionic component leads to CIS‐based QLECs exceeding 350 cd m−2 in brightness. [ABSTRACT FROM AUTHOR]

This review surveys the design of cyclometallated iridium(III) complexes for applications in light-emitting electrochemical cells (LECs). Typical iridium-containing ionic transition metal complexes (Ir-iTMCs) are of the general type [Ir(C^N) 2 (N^N)] + where H(C^N) is a cyclometallating ligand and N^N is a 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen) or related, chelating ligand. In a more recently introduced series of emitters, the N^N ligand has been replaced by a heterocyclic carbene. Since single component white-light emitting LECs are difficult to design, a more common approach is through colour-mixing. Colour-tuning of [Ir(C^N) 2 (N^N)] + emissions is achieved by manipulation of the C^N and/or N^N units because the HOMO and LUMO are, respectively, localized on the Ir/C^N or N^N domains. This review surveys synthetic strategies to Ir-iTMCs and illustrates the way in which ligand design can address emission colour and LEC stability. We consider the different approaches used to obtain blue-emitters; highly efficient and stable deep-blue emitters are required to complement the wide variety of orange emitting Ir-iTMCs for application in white-light devices. We also review the ways in which deep-red-emitting Ir-iTMCs are accessed. In addition to targeting changes in the Ir-iTMC band-gap and therefore the colour of the emission, ligand-design is critical to improving LEC stability and turn-on times; only a handful of stable deep-red-emitting LECs have been reported. One successful strategy for improving device lifetime is the introduction of intra-cation π-stacking interactions which protect the iridium metal centre in the excited state of the complex; however, a wide range of investigations suggests that the choice of stacked rings is significant and that the involvement of the cyclometallated ring(s) may be important. There are now many data to confirm that the presence of peripheral bulky substituents is beneficial, resulting in greater spatial separation of the Ir-iTMC cations in the solid state which, in turn, reduces self-quenching. Finally, we comment on why it is often difficult to legitimately compare results of different investigations of LEC performances. [ABSTRACT FROM AUTHOR]

The structure–property relationship of carborane-embedded cationic iridium(iii) complexes was investigated in this work, especially with donor–acceptor-type ligands. Firstly, an efficient synthetic approach for the new donor–acceptor-type ligands (2 and 4) was developed. By using these ligands, novel iridium(iii) complexes II and IV were prepared. Complex IV shows about a 92 nm red-shift in solution (ΦP = 0.13 in ethanol), and the emission color has an obvious change from green to red when compared with the Model complex. In addition, the photophysical characteristics of complex IV are quite sensitive to the oxygen level in living cells, based on which endocellular hypoxia imaging of complex IV has been realized by the phosphorescence lifetime imaging microscopy (PLIM) technology. Besides the experimental studies, density functional theory (DFT) and time dependent DFT (TD-DFT) calculations have been successfully applied to investigate the excited-state electronic structures of carborane-modified iridium complexes. [ABSTRACT FROM AUTHOR]

A butterfly shaped phenothiazine based electroluminescent material PPPSO2 was synthesized as an ionic small molecule emitter for light-emitting electrochemical cells (LECs). PPPSO2 shows deep blue emission in solution with high fluorescent quantum yield of 0.49. By employing the active molecule PPPSO2 as an emitter in LECs, the device shows electroluminescence centered at 498 nm with CIE coordinates of (0.21, 0.31) and maximum luminance of 509 cd m−2. The results show that the versatility of phenothiazine based luminescent materials such as high thermal stability and different emission color by tuning the oxidation state makes phenothiazine derivatives a prospective material for light-emitting devices. [ABSTRACT FROM AUTHOR]

Recently, white solid-state light-emitting electrochemical cells (LECs) have drawn great attention since they exhibit advantages such as low-voltage operation, compatibility with solution processes and employing inert cathode metals. Since different correlated color temperatures (CCTs) of background illumination are necessary for various lighting applications, a real-time tunable CCT of white LECs would be highly desired in modern smart lighting systems. In this work, a widely and dynamically tuning CCT (>10000 K) of white LEC is demonstrated by employing an electrochromic device (ECD) as a real-time controllable color filter. By increasing the applied bias on the ECD to attenuate more the red parts of white EL from the white LEC, the LEC-based white light source becomes more bluish and, in consequence, shows higher CCT. This proposed LEC-based white light source with the characteristics of wide CCT range and real-time tunability is suitable for most lighting applications and modern smart lighting systems. [ABSTRACT FROM AUTHOR]

Light-emitting electrochemical cells (LECs) can be fabricated as a single emissive organic/salt layer sandwiched between two electrodes, offering cost-effective next generation signage and lighting applications. Cyanine dyes are especially attractive to exploit the low cost potential of LECs. Cyanines denote a large class of fluorescent organic salts with tuneable emission wavelength, inherent conductivity for ionic and electronic charges, and many cyanines are commercially available at low cost. We systematically tested a set of cyanine dyes for visible emitting LECs. To circumvent non-radiative quenching processes in pure cyanine films (monomer fluorescence quantum yields, PLQE, < 1.5%) we exploited the efficient resonance energy transfer (RET) from cyanine host to cyanine guest molecules (PLQE maximum = 16.2%). The analysis indicated that specific host-guest interactions or a parallel energy transfer channel to host dimers can reduce the guest PLQE, despite a generally high RET efficiency in cyanine host-guest systems. By comparing single component with host-guest LECs, we found that the PLQE enhancement directly translated into the device efficiency increase, and red-emitting host-guest LECs with an external quantum efficiency (EQE) of 0.36% were achieved, close to the theoretical EQE maximum (0.81%). Chemical approaches that provide sterically demanding (to increase the PLQE) and high bandgap (for emission at smaller wavelengths) cyanines at low cost promise further progress in the field. [ABSTRACT FROM AUTHOR]

Hence, as a contribution to the current ecological transition, we demonstrate the valorization/upcycling of wastewaters, generated during the staining process, through the functionalization and use of the reduced ( I leuco i ) form of a vat dye, namely, violet 10, also known as isoviolanthrone. Keywords: vat dyes; upcycling; organic electronics; waste valorization; light emitting electrochemical cells EN vat dyes upcycling organic electronics waste valorization light emitting electrochemical cells 1 1 1 03/17/23 20230314 NES 230314 B Produced at a ton scale b for textile industries, vat dyes have a significant environmental impact as they are considered major water contaminants. Vat dyes, upcycling, organic electronics, waste valorization, light emitting electrochemical cells. [Extracted from the article]

The design, fabrication and operation of a range of functional power converter circuits, based on diode-configured organic field-effect transistors as the rectifying unit and capable of transforming a high AC input voltage to a selectable DC voltage, are presented. The converter functionality is demonstrated by selecting and tuning its constituents so that it can effectively drive a low-voltage organic electronic device, a light-emitting electrochemical cell (LEC), when connected to high-voltage AC mains. It is established that the preferred converter circuit for this task comprises an organic full-wave rectifier and a regulation resistor but is void of a smoothing capacitor, and that such a circuit connected to the AC mains (230 V, 50 Hz) successfully can drive an LEC to bright luminance (360 cd m −2 ) and high efficiency (6.4 cd A −1 ). [ABSTRACT FROM AUTHOR]

Construction of intramolecular π-π packing between cyclometalated and ancillary ligand have been proved to be a feasible way to design cationic Ir(III) phosphors for stable light-emitting electrochemical cells (LECs). Employing blue-green ( C1 ) and yellow-emitting ( C2 ) Ir(III) complexes as emitters, in which such π-π interactions between ligands occur, the stable and efficient LECs with peak current efficiency of 21.9 cd/A and 20.3 cd/A, respectively, were realized. To achieve the white electroluminescence, herein, a new red-emitting cationic Ir (III) complex ( C3) using 2-(5-phenyl-2-phenyl-2 H -1,2,4-triazol-3-yl)pyridine as ancillary ligand was designed and synthesized. A warm white light emitting, by doping C3 into the blue-green emitting C1 , exhibits the current efficiency of 10.1 cd/A. In addition, the obtained LECs are more stable than those of previous reports due to presence of intrinsic super-cage structures in the systems. The results indicate that the efficient white LECs hold promising applications in the practical solid state lighting. [ABSTRACT FROM AUTHOR]

Self-propelled micromotors offer considerable promise to solve electroanalytical challenges. This timely review provides a comprehensive overview of the potential of Janus micromotors for new electroanalytical and biosensing applications. We will describe first the use of Janus micromotors to assist electrochemical measurements using strip-based microvolume electrodes. Recent advances on actively moving electrochemical (bio)sensors, ranging from enzyme-powered to light-emitting electrochemically powered Janus micromotors, will be also described. We hope that this Review provides the reader with some general knowledge and future prospect of the potential of Janus micromotors for electroanalysis. [ABSTRACT FROM AUTHOR]

This paper presents a ray tracing visualization technique to generate realistic images of turbulent non-sooting hydrocarbon flames. The method uses flamelet libraries to reconstruct the flame structure in physical space, calculating the light emitted in the visual range of light emitting radicals present in the flame. The generated visualizations clearly convey the complex structure of turbulent flames and provide a vehicle for presenting complex simulations of turbulent flames to the general public. [ABSTRACT FROM AUTHOR]

Nowadays, the design and development of novel phosphorescent iridium(III) complexes for various optoelectronic applications is a well-recognized area of research. The fascinating photophysical properties of iridium(III) compounds are strongly influenced by the spin-orbit coupling exerted by the iridium(III) core, usually resulting in intense emissions with short excited-state lifetimes, which can be precisely controlled with the aid of molecular engineering of the chelating ligand. This review focuses on the recent developments and state of the art knowledge on phosphorescent iridium(III) compounds, especially on heteroleptic complexes derived from 2,3′-bipyridine class of cyclometalating and ancillary ligands, highlighting the excited state phenomenon behind their emission behavior. [ABSTRACT FROM AUTHOR]

The synthesis of four cyclometallated [Ir(C^N)2(N^N)][PF6] compounds in which N^N is a substituted 2,2′-bipyridine (bpy) ligand and the naphthyl-centred ligand 2,7-bis(2-(2-(4-(pyridin-2-yl)phenoxy)ethoxy)ethoxy)naphthalene provides the two cyclometallating C^N units is reported. The iridium(iii) complexes have been characterized by 1H and 13C NMR spectroscopies, mass spectrometry and elemental analysis, and their electrochemical and photophysical properties are described. Comparisons are made with a model [Ir(ppy)2(N^N)][PF6] compound (Hppy = 2-phenylpyridine). The complexes containing the naphthyl-unit exhibit similar absorption spectra and excitation at 280 nm leads to an orange emission. The incorporation of the naphthalene unit does not lead to a desirable blue contribution to the emission. Density functional theory calculations were performed to investigate the geometries of the complexes in their ground and first triplet excited states, as well as the energies and compositions of the highest-occupied and lowest unoccupied molecular orbital (HOMO and LUMO) manifolds. Trends in the HOMO–LUMO gaps agree with those observed electrochemically. The energy difference between the LUMO and the lowest unoccupied MO located on the naphthyl unit (LUMO+7) is large enough to explain why there is no contribution from the naphthyl-centred triplet excited state to the phosphorescence emission. Singlet excited states were also investigated. Light-emitting electrochemical cells (LECs) using the [Ir(C^N)2(N^N)][PF6] and [Ir(ppy)2(N^N)][PF6] complexes in the emissive layer were made and evaluated. The presence of the naphthyl-bridge between the cyclometallating units does not significantly alter the device response. [ABSTRACT FROM AUTHOR]

Acridines play an important role in various fields of sciences. Besides their application for treatment of a number of infections, cancer, viral and prion diseases, they have been extensively used in chemiluminescence. Electrochemiluminescence (ECL) is a unique kind of chemiluminescence with the precise temporal and spatial control of light emitting reactions by utilizing electrochemistry techniques. These advantages result in increasing attention towards acridines ECL. This review summarizes acridines used in ECL, ECL mechanisms, strategies for increasing ECL intensities, and ECL analytical applications, as well as prospects the future development of acridine ECL. [ABSTRACT FROM AUTHOR]

ABSTRACT Donor-π-acceptor type fluorene-based copolymers with a sulfone unit were designed and synthesized for application in efficient pure-blue light emitting. The electroluminescence behaviors of these copolymers were investigated by fabricating light-emitting diodes and electrochemical cell devices. The former device little functioned but the latter worked well. The electrochemical cell devices having a configuration of ITO/PEDOT:PSS/copolymer:ionic liquid/Al exhibited purplish blue electroluminescence with an emission maximum at 434 nm (CIE coordinates ( x, y) = (0.17, 0.10)) measured at 7 V. The initial positive scan of the D-π-A polysulfone based light emitting electrochemical cell with a sweep rate of 0.1 V s−1 afforded a maximum luminance of 1080 cd m−2 with a current efficiency of 1.96 cd A−1 at an operating voltage of 12.5 V. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3454-3461 [ABSTRACT FROM AUTHOR]

A series of heteroleptic [Cu(N^N)(P^P)][PF6] complexes is described in which P^P = bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos) and N^N = 4,4′-diphenyl-6,6′-dimethyl-2,2′-bipyridine substituted in the 4-position of the phenyl groups with atom X (N^N = 1 has X = F, 2 has X = Cl, 3 has X = Br, 4 has X = I; the benchmark N^N ligand with X = H is 5). These complexes have been characterized by multinuclear NMR spectroscopy, mass spectrometry, elemental analyses and cyclic voltammetry; representative single crystal structures are also reported. The solution absorption spectra are characterized by high energy bands (arising from ligand-centred transitions) which are red-shifted on going from X = H to X = I, and a broad metal-to-ligand charge transfer band with λmax in the range 387–395 nm. The ten complexes are yellow emitters in solution and yellow or yellow-orange emitters in the solid-state. For a given N^N ligand, the solution photoluminescence (PL) spectra show no significant change on going from [Cu(N^N)(POP)]+ to [Cu(N^N)(xantphos)]+; introducing the iodo-functionality into the N^N domain leads to a red-shift in λmaxem compared to the complexes with the benchmark N^N ligand 5. In the solid state, [Cu(1)(POP)][PF6] and [Cu(1)(xantphos)][PF6] (fluoro-substituent) exhibit the highest PL quantum yields (74 and 25%, respectively) with values of τ1/2 = 11.1 and 5.8 μs, respectively. Light-emitting electrochemical cells (LECs) with [Cu(N^N)(P^P)][PF6] complexes in the emissive layer have been tested. Using a block-wave pulsed current driving mode, the best performing device employed [Cu(1)(xantphos)]+ and this showed a maximum luminance (Lummax) of 129 cd m−2 and a device lifetime (t1/2) of 54 h; however, the turn-on time (time to reach Lummax) was 4.1 h. Trends in performance data reveal that the introduction of fluoro-groups is beneficial, but that the incorporation of heavier halo-substituents leads to poor devices, probably due to a detrimental effect on charge transport; LECs with the iodo-functionalized N^N ligand 4 failed to show any electroluminescence after 50 h. [ABSTRACT FROM AUTHOR]

The differences in the electroluminescence (EL) of red-emitting free-base ( H2TPP) and Zn-metalated ( ZnTPP) archetypal porphyrins are rationalized in light-emitting electrochemical cells by means of an electric-field dependent effect, leading to whitish and reddish devices, respectively. Although H2TPP shows superior electrochemical and photophysical features compared to ZnTPP, devices prepared with ZnTPP surprisingly stand out with a deep-red EL similar to its photoluminescence (PL), while H2TPP devices feature unexpected whitish EL. Standard arguments such as degradation, device architecture, device mechanism, and changes in the nature of the emitting excited states are discarded. Based on electrochemical impedance spectroscopy and first-principles electronic structure methods, we provide evidence that the EL originates from two H2TPP regioisomers, in which the inner ring H atoms are placed in collinear and vicinal configurations. The combination of their optical features provides an explanation for both the high- and low-energy EL features. Here, the emitting excited state nature is ascribed to the Q bands, since the Soret excited states remain high in energy. This contrasts to what is traditionally postulated in reports focused on H2TPP lighting devices. Hence, this work provides a new explanation for the nature of the high-energy EL band of H2TPP that might inspire future works focused on white-emitting molecular-based devices. [ABSTRACT FROM AUTHOR]

The syntheses, photophysical/electrochemical characterizations of different metallated porphyrins –i.e., Zn2+, Pt2+, Pd2+, and Sn4+ porphyrins – as well as their first application in light-emitting electrochemical cells are provided. A direct comparison demonstrates that depending on the metallation either efficient (Pt-por) or stable (Zn-por) devices are achieved, demonstrating that the choice of the metal core is a key aspect for future developments. [ABSTRACT FROM AUTHOR]

We present a study of the electrical properties of electrochemically doped conjugated polymers using polymeric light-emitting electrochemical cells (PLECs) and interpreting the results according to a phenomenological model (PM) which assumes that, above the device turn-on voltage, the bulk transport properties of the doped organic semiconductor are responsible for the main contribution to the whole device conductivity. To confirm the predictions of this model, the dependence of the conductivity of PLECs with different parameters is evaluated and compared with the behavior expected for a doped semiconducting polymeric material. The organic semiconductor doping level, the blend concentration of organic semiconducting molecules, the device thickness, the charge carrier mobility, and the temperature are the parameters varied to perform this analysis. We observed that the device conductivity is independent of the active layer thickness, weakly dependent on the temperature, but strongly dependent on the semiconductor doping level, on the semiconductor fraction in the blend, and on the intrinsic charge carrier mobility. These results were well described by the variable range hopping (VRH) model, which has been widely employed to describe the charge transport in doped semiconducting polymeric materials, confirming the prediction of the phenomenological model. The current analysis demonstrates that PLECs are a suitable system for studying, in situ, the electrochemical doping of semiconducting polymers, permitting the evaluation of material properties as, for instance, the density of electronic charge carriers (and, consequently, the ionic charge carrier concentration) necessary to achieve the maximum electrochemical doping level of the organic semiconductor. [ABSTRACT FROM AUTHOR]

We report the use of a straightforward alternative accelerated lifetime test (ALT) method, derived from general electrical principles, for estimating how encapsulated light-emitting electrochemical cells (LECs) operate in ambient conditions. The LECs that we tested were made with poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV), poly(ethylene oxide) (PEO), trifluoromethanesulfonate (KCF 3 SO 3 ) and PEDOT:PSS. These LECs were fabricated by using a common method that is described in published investigations of operational lifetime. The method we developed used only a single data point originating from a high level of current density, and could predict the operational lifetimes of the encapsulated LECs to within a margin of error of less than 4% in this system. [ABSTRACT FROM AUTHOR]

This work provides the synthesis, structural characterization, electrochemical and photophysical features, as well as the application in light-emitting electrochemical cells (LECs) of a novel heteroleptic copper(i) complex – [Cu(impy)(POP)][PF6], where impy is 3-(2-methoxyphenyl)-1-(pyridine-2-yl)imidazo[1,5-a]pyridine and POP is bis{2-(diphenylphosphanyl)phenyl}ether. This compound shows blue photoluminescence (PL, λ = 450 nm) in solution and solid-state and excellent redox stability. Despite these excellent features, the electroluminescence (EL) response is located at ∼550 nm. Although the EL spectrum of LECs is typically red-shifted compared to the PL of the electroluminescent material, a shift of ca. 100 nm represents the largest one reported in LECs. To date, the large shift phenomena have been attributed to (i) a change in the nature of the lowest emitting state due to a concentration effect of the films, (ii) a reversible substitution of the ligands due to the weak coordination to the Cu(i), and (iii) a change in the distribution of the excited states due to polarization effects. After having discarded these along with others like the irreversible degradation of the emitter during device fabrication and/or under operation conditions, driving conditions, active layer composition, and changes in the excited states under different external electrical stimuli, we attribute the origin of this unexpected shift to a lack of a thermally activated delayed fluorescence (TADF) process due to the solely ligand-centered character of the excited states. As such, the lack of a charge transfer character in the excited states leads to a blue-fluorescence and yellow-phosphorescence photo- and electro-responses, respectively. This corroborates recent studies focused on the design of TADF for heteroleptic copper(i) complexes. Overall, this work is a clear insight into the design of new copper(i) complexes towards the preparation of blue LECs, which are still unexplored. [ABSTRACT FROM AUTHOR]

Light-Emitting Electrochemical Cells (LECs) with a simple device structure ITO/Ru complex/Ga:In were prepared by using heteroleptic ruthenium(ii) complexes containing 2-(2-hydroxyphenyl)-1-(4-bromophenyl)-1h-imidazo[4,5-f][1,10]phenanthroline (hpbpip) as the π-extended ligand. After ancillary ligand modification, the [Ru(hpbpip)(dmbpy)2](ClO4)2 complex shows a deep red electroluminescence emission (2250 cd m−2 at 6 V) centered at 685 nm, 65 nm red-shifted compared to the [Ru(bpy)3](ClO4)2 benchmark red-emitter at a very low turn voltage (2.6 V), demonstrating its potential for low-cost deep-red light sources. Moreover, the PL quantum yield of the [Ru(hpbpip)(bpy)2](ClO4)2 complex was revealed to be higher (0.121) than the benchmark standard [Ru(bpy)3]2+ (0.095). [ABSTRACT FROM AUTHOR]

We report the synthesis of four cationic iridium complexes, [Ir(ppy) 2 (mepzpy)]PF 6 ( 1a ), [Ir(dfppy) 2 (mepzpy)]PF 6 ( 1b ), [Ir(ppy) 2 (dmpzpy)]PF 6 ( 2a ), and [Ir(dfppy) 2 (dmpzpy)]PF 6 ( 2b ), containing the methyl-substituted pyrazole-based ancillary ligand and the phenylpyridine-based cyclometalating ligands. UV–visible, photoluminescence (PL), and voltammetric measurements were made to study the photophysical and electrochemical properties of complexes 1a – 2b . Light-emitting electrochemical cells (LECs) were fabricated, which showed yellow emission for complexes 1a and 2a and green emission for complexes 1b and 2b . The LEC incorporating 2b exhibited a high luminance of 658 cd m −2 and a current efficiency of 0.34 cd A −1 . The higher luminance and efficiency of the device based on 2b were due to the smooth surface morphology and the presence of sterically hindered dimethyl groups on the ancillary ligand (dmpzpy), which causes a more balanced charge carrier injection and recombination. [ABSTRACT FROM AUTHOR]

Polymer light-emitting electrochemical cells (LECs) are inherently dependent on a suitable electrolyte for proper function. Here, we design and synthesize a series of alkyl carbonate-capped star-branched oligoether-based electrolytes with large electrochemical stability windows, facile ion release, and high compatibility with common light-emitting materials. LECs based on such designed electrolytes feature fast turn-on, a long operational lifetime of 1400 h at >100 cd m-2 and a record-high power conversion efficiency of 18.1 lm W-1, when equipped with an external outcoupling film. [ABSTRACT FROM AUTHOR]

Intermediate band solar cells are a new generation of photovoltaics that allow for better utilization of the solar spectrum. The key and most challenging requirement for these cells is an efficient optical coupling between the intermediate band and the charge conducting bands. GaNAs based intermediate band solar cells have been used to generate electroluminescence. Two electroluminescence peaks are generated in the structure with electrically blocked intermediate band. The peaks are observed for both forward and reverse bias configuration and are attributed to optical transitions from the conduction to the intermediate band, and from the intermediate band to the valence band. The origin of the electroluminescence is confirmed by the temperature dependence of the electroluminescence peak energies that is consistent with the band anticrossing model of the intermediate band formation in dilute nitride alloys. This is the first direct observation of the optical transitions required for the operation of intermediate band solar cells. The results also demonstrate that properly modified intermediate band solar cell structures could be used as multicolor light emitters. [ABSTRACT FROM AUTHOR]

We report two unprecedent alkynyl bridging cyclometalated clusters [Ir2M2(ppy)4(μ-C≡CC6H4-OMe3)4] where M is Ag (2) and Cu (3), which display distinctive luminescence properties. While 2 features a green phosphorescence/electroluminescence nature located at the ppy ligands (3LC), 3 shows an orange emission confined to the metals and alkynyl groups having a mixed 3L′C/3L′MCT/3MMCT (L′ = alkynyl) nature. [ABSTRACT FROM AUTHOR]

Six new tricationic IrIII complexes of cyclometalating ligands derived from 1-methyl-2-(2′-pyridyl)pyridinium or 1-methyl-4-(2′-pyridyl)pyridinium are described. These complexes of the form [IrIII(C^N)2(N^N)]3+ (C^N = cyclometalating ligand; N^N = α-diimine) have been isolated and characterised as their PF6− and Cl− salts. Four of the PF6− salts have been studied by X-ray crystallography, and structures have been obtained also for two complex salts containing MeCN and Cl− or two Cl− ligands instead of N^N. The influence of the position of the quaternised N atom in C^N and the substituents on N^N on the electronic/optical properties are compared with those of the analogous complexes where C^N derives from 1-methyl-3-(2′-pyridyl)pyridinium (B. J. Coe, et al., Dalton Trans., 2015, 44, 15420). Voltammetric studies reveal one irreversible oxidation and multiple reduction processes which are mostly reversible. The new complexes show intramolecular charge-transfer absorptions between 350 and 450 nm, and exhibit bright green luminescence, with λmax values in the range 508–530 nm in both aqueous and acetonitrile solutions. In order to gain insights into the factors that govern the emission properties, density functional theory (DFT) and time-dependent DFT calculations have been carried out. The results confirm that the emission arises largely from triplet excited states of the C^N ligand (3LC), with some triplet metal-to-ligand charge-transfer (3MLCT) contributions. [ABSTRACT FROM AUTHOR]

While perovskite light-emitting diodes typically made with high work function anodes and low work function cathodes have recently gained intense interests. Perovskite light-emitting devices with two high work function electrodes with interesting features are demonstrated here. Firstly, electroluminescence can be easily obtained from both forward and reverse biases. Secondly, the results of impedance spectroscopy indicate that the ionic conductivity in the iodide perovskite (CH3NH3PbI3) is large with a value of ≈10−8 S cm−1. Thirdly, the shift of the emission spectrum in the mixed halide perovskite (CH3NH3PbI3−xBrx) light-emitting devices indicates that I− ions are mobile in the perovskites. Fourthly, this work shows that the accumulated ions at the interfaces result in a large capacitance (≈100 μF cm−2). The above results conclusively prove that the organic–inorganic halide perovskites are solid electrolytes with mixed ionic and electronic conductivity and the light-emitting device is a light-emitting electrochemical cell. The work also suggests that the organic–inorganic halide perovskites are potential energy-storage materials, which may be applicable in the field of solid-state supercapacitors and batteries. [ABSTRACT FROM AUTHOR]

The synthesis, structures and photophysical properties of a series of bis-cyclometallated Ir(iii) complexes bearing phenylpyrazole (ppz) cyclometallating ligands and phenanthroline-based ancillary ligands containing thienyl- and bithienylamido groups are reported. All complexes are emissive in solution, while in PMMA films strong emission is observed from the thienylamido substituted complex with no emission from the bithienylamido complex. The bithienylamido substituted complex has an excited state lifetime which is significantly longer than the emission lifetime, attributed to the population of non-equilibrated 3MLCT and 3LC states in this complex. This represents a rare example of this unusual excited state behaviour. DFT calculations show that the emitting 3MLCT state and the dark 3LC state on bithiophene are close in energy and that a large change in the triplet state geometry occurs upon excitation that effectively lowers the energy of the 3MLCT state below that of the dark 3LC state. The low quantum yield of the bithienylamido complex is attributed to a structural rearrangement upon relaxation back to the ground state, opening a non-radiative decay pathway. [ABSTRACT FROM AUTHOR]

A novel concept for the light-emitting electrochemical transistor (LECT) which consists of the electrochemical light-emitting cell (LEC) and the electrochemical transistor (ECT) was introduced. The four-electrode electrochemical system using interdigitated array (IDA) electrodes was employed to demonstrate the concept of LECT in solution. Cyclic voltammetric (CV) measurement was carried out in solution containing Ru(bpy)3(PF6)2as redox species and a light-emitting material. We confirmed that the light emission was controlled at the electrode potential difference between both fingers of IDA electrodes. [ABSTRACT FROM AUTHOR]

A solution-based fabrication of flexible and light-weight light-emitting devices on paper substrates is reported. Two different types of paper substrates are coated with a surface-emitting light-emitting electrochemical cell (LEC) device: a multilayer-coated specialty paper with an intermediate surface roughness of 0.4 μm and a low-end and low-cost copy paper with a large surface roughness of 5 μm. The entire device fabrication is executed using a handheld airbrush, and it is notable that all of the constituent layers are deposited from solution under ambient air. The top-emitting paper-LECs are highly flexible, and display a uniform light emission with a luminance of 200 cd m−2 at a current conversion efficacy of 1.4 cd A−1. [ABSTRACT FROM AUTHOR]

The great success of electrochemiluminescence (ECL) for in vitro diagnosis (IVD) and its promising potential in light-emitting devices greatly promote recent ECL studies. More than 45% of ECL articles were published after 2010, and the first international meeting on ECL was held in Italy in 2014. This critical review discusses recent vibrant developments in ECL, and highlights novel ECL phenomena, such as wireless ECL devices, bipolar electrode-based ECL, light-emitting electrochemical swimmers, upconversion ECL, ECL resonance energy transfer, thermoresponsive ECL, ECL using shape-controlled nanocrystals, and ECL as an ion-selective electrode photonic reporter, a paper-based microchip, and a self-powered microfluidic ECL platform. We also comment on the latest progress in bioassays, light-emitting devices and, the computational approach for the ECL mechanism study. Finally, perspectives and key challenges in the near future are addressed (198 references). [ABSTRACT FROM AUTHOR]

Recently, solid-state light-emitting electrochemical cells (LECs) based on ionic transition metal complexes (iTMCs) have attracted much research interest since they have the advantages of a simple device structure, a low operation voltage and compatibility with air-stable electrodes. These properties enable LECs to be cost-effective, versatile and power-efficient organic light-emitting sources. However, it is generally not easy to modify the molecular structure to achieve balanced carrier mobilities without altering the photoluminescence quantum yield of the iTMC. Furthermore, the carrier balance and the consequent device efficiency of single-layered LECs would not be easy to optimize since no carrier injection and transport layers can be used. In this perspective, some reported techniques to improve carrier balance of LECs based on iTMCs are described and reviewed. The importance and impact of these studies are highlighted. The effects on device lifetime and turn-on time because of employing these techniques to improve the carrier balance are also discussed. This perspective concludes that even with electrochemically doped layers, improving the carrier balance of LECs would be required for realizing efficient electroluminescent emission from simple-structure organic light-emitting sources. [ABSTRACT FROM AUTHOR]

Green- and yellow-emitting cationic iridium complexes, [Ir(dfppy) 2 (pybi)]PF 6 (Complex 1) and [Ir(ppz) 2 (pybi)]PF 6 (Complex 2), were synthesized using 2-(2,4-difluorophenyl)pyridine (Hdfppy) and 1-phenylpyrazole (Hppz) as the cyclometalating ligands and 2-(2-pyridyl)benzimidazole (pybi) as the ancillary ligand. In order to gain insight into the photophysical and electrochemical behavior, density functional theory (DFT) calculations were simulated on the above complexes, which showed consistency in energy gaps obtained from both experimental and theoretical results. Light-emitting electrochemical cells (LECs) based on Complex 1 were obtained by solution-processed fabrication, and they showed green (523 nm) electroluminescence with Commission Internationale de L'Eclairage (CIE) coordinates of (0.33, 0.58); on the other hand, the LEC utilizing Complex 2 showed yellow electroluminescence with CIE coordinates of (0.41, 0.56). The highest luminance of 1492 cd m −2 and current density of 83.13 mA cm −2 were achieved for the LEC utilizing Complex 2, owing to the more balanced carrier injection and recombination as compared to those for Complex 1. The negative role of the free – NH group in the electroluminescent properties of LECs is confirmed by comparing the current results with those previously reported for N-alkylated benzimidazole moieties. [ABSTRACT FROM AUTHOR]

The emergence of wearable electronics and optoelectronics requires the development of devices that are not only highly flexible but can also be woven into textiles to offer a truly integrated solution. Here, we report a colour-tunable, weavable fibre-shaped polymer light-emitting electrochemical cell (PLEC). The fibre-shaped PLEC is fabricated using all-solution-based processes that can be scaled up for practical applications. The design has a coaxial structure comprising a modified metal wire cathode and a conducting aligned carbon nanotube sheet anode, with an electroluminescent polymer layer sandwiched between them. The fibre shape offers unique and promising advantages. For example, the luminance is independent of viewing angle, the fibre-shaped PLEC can provide a variety of different and tunable colours, it is lightweight, flexible and wearable, and it can potentially be woven into light-emitting clothes for the creation of smart fabrics. [ABSTRACT FROM AUTHOR]