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- 摘要
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- 实验方案
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Enhancing Light Outcoupling in OLEDs by Integration of Scattering Electrodes
摘要： Limited outcoupling efficiencies are still a big problem in organic light-emitting devices (OLEDs). In this contribution, a simple and general approach for enhancing the outcoupling efficiency of OLEDs is presented: by using a three-step process including electro-spray deposition of a sacrificial material (step i), thin metal-layer deposition (step ii), and elution of the sacrificial material (step iii), scattering metal structures can be fabricated that can be used in cavity OLEDs. The integration into green-emitting vacuum-processed OLEDs yields in an increased luminous efficiency and EQE by 30% and 27%, respectively.
关键词： OLED,Electrospray Deposition,Organic Electronics,Light Outcoupling
更新于2025-11-14 15:25:21
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Rational Interface Engineering for Efficient Flexible Perovskite Light-Emitting Diodes
摘要： Although perovskite light-emitting diodes (Pe-LEDs) are promising for next-generation displays and lighting, their efficiency is still considerably below that of conventional inorganic and organic counterparts. Significant efforts in various aspects of the electroluminescence process are required to achieve high-performance PeLEDs. Here, we present an improved flexible PeLED structure based on the rational interface engineering for energy-efficient photon generation and enhanced light outcoupling. The interface-stimulated crystallization and defect passivation of the perovskite emitter are synergistically realized by tuning the underlying interlayer, leading to the suppression of trap-mediated nonradiative recombination losses. Besides approaching highly emissive perovskite layers, the outcoupling of trapped light is also enhanced by combining the silver nanowires-based electrode with quasi-random nanopatterns on flexible plastic substrate. Upon the collective optimization of the device structure, a record external quantum efficiency of 24.5% is achieved for flexible PeLEDs based on green-emitting CsPbBr3 perovskite.
关键词： defect passivation,flexible perovskite light-emitting diodes,perovskite light-emitting diodes,silver nanowires,light outcoupling
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 2nd International Conference on Electronics Technology (ICET) - Chengdu, China (2019.5.10-2019.5.13)] 2019 IEEE 2nd International Conference on Electronics Technology (ICET) - Light Outcoupling Integrated Photonic Crystals for OLEDs
摘要： To develop an efficient light outcoupling strategy to improve the efficiency and viewing of organic light emitting diodes (OLEDs) could be beneficial for display application. We propose a hybrid mode formed by integrating a photonic crystal structure on the semitransparent metal electrode of OLEDs to enhance the light outcoupling efficiency and viewing characteristics. The hybrid mode was realized through excite both tamm plasmon mode and microcavity mode.
关键词： OLEDs,tamm plasmon,photonic crystals,light outcoupling
更新于2025-09-16 10:30:52
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Comment on “Improving Light Outcoupling Efficiency for OLEDs with Microlens Array Fabricated on Transparent Substrate”
摘要： The recently published research article, titled “Improving Light Outcoupling Efficiency for OLEDs with Microlens Array Fabricated on Transparent Substrate,” provides a significant design rule for the high extraction efficiency of OLED devices. According to the simulation results, the authors proposed that a well-organized microlens-embedding structure may increase 80% light output efficiency. For an experimental demonstration, about 30% luminance enhancement was induced by a microlens-arrayed substrate. The optical lens design was applied and revealed a noticeable improvement of OLED performances. The authors demonstrated the improved OLED performances by using geometric designs of microlens arrays, which are formed on a glass substrate. The microlens arrays were formed by photoresist material. The photoresist film showed high transmittance above 90% for longer wavelengths (λ>500 nm); however, the photoresist microlens arrays have no electrical advantages for carrier transportation. Meanwhile, we also consider an electrical aspect for further significant enhancement for photoelectric devices, including LEDs and solar cells. A distinctive feature between LEDs and solar cells is a way to utilize energy conversion. LEDs convert the electric energy to light emission and solar cells generate electric power from the incident photon energy. This basic and important understanding may provide mutual applications of photoelectric devices. Previously, we have investigated an indium-tin-oxide (ITO) transparent conducting layer to focus the incident light into the light-reactive semiconducting material. The nanoscale ITO nanodome arrays efficiently focus the incoming light resulting in the enhanced solar cell performances, based on the enlarged current value. This was caused by the optical design to manipulate the light penetration through the Si material. Additionally, the electrical aspect also contributed to increase in current value due to excellent electrical conductivity of the ITO layer, providing an efficient route to collect photogenerated carriers, effectively. This optically and electrically balanced design may be applied in the microlens-arrayed OLED devices. Instead of using the electrically nonconductive material, electrically conductive materials, such as ITO, can be considered for the light-modulating structure. This design would spontaneously provide the electrical advantages and maintain the optical benefit of light manipulation of the patterned structure. To realize these optical and electrical features, one may think of the patterned ITO arrays, which sit on the ITO anode layer. The carriers from organic (light-active) layers can easily reach the ITO anode and the emitted light can efficiently propagate through the patterned ITO arrays. Figure 1 is one of the possible schemes of the functional ITO patterns for efficient OLED. Double anode layers are proposed, where the film ITO is a conventional anode figure and the patterned ITO-array structure is for the functional light extraction. Besides the light management from the patterned ITO-array structure, the electrical conductivity would be enhanced according to double ITO layers.
关键词： OLED,transparent substrate,microlens array,ITO,light outcoupling efficiency,photoelectric devices
更新于2025-09-16 10:30:52
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Inside or outside: Evaluation of the efficiency enhancement of OLEDs with applied external scattering layers
摘要： Improving the efficiency of organic light-emitting diodes (OLEDs) by enhancing light outcoupling is common practise and remains relevant as not all optical losses can be avoided. Especially, externally attached scattering layers combine several advantages. They can significantly increase the performance and neither compromise the electric operation nor add high costs during fabrication. Efficiency evaluations of external scattering layers are often done with lab scale OLEDs. In this work we therefore study different characterization techniques of red, green and blue lab scale OLEDs with attached light scattering foils comprising TiO2 particles. Although we observe an increased external quantum efficiency (EQE) with scattering foils, our analysis indicates that areas outside the active area have a significant contribution. This demonstrates that caution is required when efficiency conclusions are transferred to large area applications, for which effects that scale with the edges become less significant. We propose to investigate brightness profiles additionally to a standard EQE characterizations as latter only work if the lateral scattering length is much smaller than the width of the active area of the OLED. Our results are important to achieve more reliable predictions as well as a higher degree of comparability between different research groups in future.
关键词： external scattering layers,efficiency enhancement,OLEDs,EQE,light outcoupling
更新于2025-09-12 10:27:22