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Organic light‐emitting devices on fabrics (Fa‐OLEDs) are outstanding candidates for high‐quality wearable displays. High flexibility and conformality to clothes deformations are required for Fa‐OLEDs to keep wearing comfort during body movement. However, it is a great challenge to realize an ultrathin planarization layer with ultrasmooth surface simultaneously on the rough surface of fabrics for Fa‐OLEDs fabrication. Here, a template‐stripping process is employed to fabricate both ultrathin and ultrasmooth planarization layers for highly flexible and efficient Fa‐OLEDs. The thickness of the planarization layer is as small as 3 µm while its surface roughness is only 0.6 nm. The planarization process is insensitive to the textures and morphology of fabrics. As a result, the Fa‐OLEDs show excellent electroluminescent performance and flexibility. The maximum current efficiency of 78 cd A−1 is comparable with that of the conventional planar devices. The variation of current efficiency is as small as 8% after 1000 times of bending with 1 mm bending radius, which is the best bending stability of the flexible Fa‐OLEDs reported to date. The Fa‐OLEDs are successfully used as conformal wearable displays by sewing on clothes and keep working well with a series of arm movements. [ABSTRACT FROM AUTHOR]

We report an ultrathin Au transparent electrode with the thickness of only 4.4 nm based on an S-1805/Ag hybrid nucleation layer and its application in flexible organic light-emitting devices (OLEDs) as the replacement of indium tin oxide (ITO) anode. The Volmer–Weber growth mode of the deposited Au film has been suppressed successfully by using the hybrid nucleation layer, in which the S-1805 acts as a substrate modification layer and 0.6 nm Ag acts as a seeding layer. The resulting ultrathin Au film with the thickness of 4.4 nm shows high transparency, high conductivity, and ultrasmooth surface. A 25% improvement in efficiency has been demonstrated for the OLEDs with ultrathin Au anodes compared to the ITO-based devices. The application of the high-performance ultrathin Au electrodes in OLEDs results in high flexibility and mechanical robustness with small performance variations after 2100 bending cycles with a 7.5 mm bending radius. [ABSTRACT FROM AUTHOR]

The demonstration of high efficiency and color tunability has brought organic light-emitting devices (OLEDs) into the lighting and display market. High efficiency is one of the key issues for their commercial applications, for which much effort has been devoted to developing novel materials and device structures. It is well known that around 80% of the generated photons are trapped in OLED structure, so that there is still the greatest scope for significant improvements in its efficiency. This has driven the research towards the integration of micro/nano patterns into device structures that benefit from their abilities in manipulating the generation and propagation of photons. Micro/nano patterns with random or periodic morphologies have demonstrated their effect on the outcoupling of the trapped photons within the device. Moreover, the emitting properties other than the light extraction could be manipulated by introducing the micro/nano patterns. This article reviews the recent progresses in improving the light extraction and manipulating the emission properties of the OLEDs through the introduction of the micro/nano patterns by various fabrication strategies. The light manipulation of the micro/nano patterns in organic photovoltaics is briefly discussed considering its similar working principle and fabrication strategies to that of the OLEDs. [ABSTRACT FROM AUTHOR]

Fe3O4 has been demonstrated to be an efficient p-dopant in improving the performance of organic light-emitting devices. This paper investigates in detail the role of Fe3O4 in improving the hole injection and the hole transport by the ultraviolet/visible/near-infrared absorption, x-ray, and ultraviolet photoelectron spectroscopy. The results demonstrated that Fe3O4 as a p-dopant has different effectiveness when it is doped into different host materials. The improved properties of the OLEDs with the p-doped N, N'-diphenyl-N,N'-bis (1,1'-biphenyl)-4,4'-diamine layer is mainly due to the enhanced hole injection through the lowering of the hole injection barrier, while the enhanced hole transport plays a more important role for the OLEDs with the p-doped 4,4',4”-tris (3-methylphenylphenylamino) triphenylamine due to their higher ability in the formation of charge transfer complex. [ABSTRACT FROM PUBLISHER]

We have demonstrated an indium-tin-oxide free organic light-emitting device (OLED) with improved efficiency by doping poly (3,4-ethylene dioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) with graphene oxide (GO) as a composite anode. In comparison with a pure PEDOT:PSS anode, 55% enhancement in efficiency has been obtained for the OLEDs based on the PEDOT:PSS/GO composite anode at an optimal condition. The PEDOT:PSS/GO composite anode shows a lower hole-injection barrier, which contributes to the improved device efficiency. Moreover, both high transmittance and good surface morphology similar to that of the pure PEDOT:PSS film also contribute to the enhanced efficiency. It is obvious that composite anode will generally be applicable in organic optoelectronic devices which require smooth and transparent anode. [ABSTRACT FROM AUTHOR]

Highlights: [•] An ITO-free flexible OLED with improved efficiency has been fabricated. [•] Template stripping process has been employed to fabricate the ITO-free OLEDs. [•] The smoothness and conductivity of the PEDOT: PSS anode has been improved. [•] The H2SO4 residues on the PEDOT: PSS anode has been eliminated. [•] The device stability has been improved by eliminating the H2SO4 residues. [ABSTRACT FROM AUTHOR]