Fabrication of an oxide/metal/oxide structured electrode integrated with antireflective film to enhance performance in flexible organic light-emitting diodes. (June 2021)

• Record Type: Journal Article
• Authors: Ko, K.-J.; Shin, S.-R.; Lee, H.B.; Jeong, E.; Yoo, Y.J.; Kim, H.M.; Song, Y.M.; Yun, J.; Kang, J.-W.
• Is Part Of: Materials today energy. Volume 20(2021)
• Publication Date: 2021-06
• Subjects: Light extraction -- Silica nanoparticles -- Refractive index -- OMO TCE -- Flexible OLED; Energy development -- Periodicals; Energy industries -- Periodicals; Power resources -- Periodicals; Energy policy -- Periodicals; Energy development; Energy industries; Energy policy; Power resources; Electronic journals; Periodicals; 621.042
• DOI: 10.1016/j.mtener.2021.100704
• Languages: English
• ISSNs: 2468-6069

Abstract

Abstract: Flexible organic light-emitting diodes (OLEDs) are used widely in optoelectronic devices, with possible new applications, including foldable/rollable displays. Unique features of flexible OLEDs included high brightness, low power consumption, and flexibility. The performance of a flexible OLED is frequently hindered by refractive index difference between the air and the flexible substrate medium, leading to inefficient light outcoupling. To address this issue, we developed a mechanically robust oxide/metal/oxide (OMO) structured transparent conducting electrode (TCE), integrated with silica nanoparticles–based antireflective (AR) film, to improve the light extraction efficiency of flexible OLEDs. The AR-OMO structures were prepared on polyethylene terephthalate substrates using a combination of plasma-enhanced chemical vapor deposition and magnetron sputtering. Our results show that an OLED device based on AR-OMO TCE exhibits higher luminance efficiency ( LE ) and total external quantum efficiency ( EQE tot ) than devices based on pristine OMO or an indium tin oxide structure due to the presence of AR film that suppresses waveguided-mode light loss at the air-substrate interface. The champion AR-OMO-based flexible OLED devices achieved an LE of 12.3 cd/A and an EQE tot of 5.0%. The AR-OMO device also demonstrated outstanding mechanical flexibility, retaining 100% of its initial luminance up to a bending radius of 6 mm. Graphical abstract: An oxide-metal-oxide (OMO) transparent conducting electrode integrated with a silica nanoparticles–based antireflective (AR) film was developed for the making of high-performance flexible organic light-emitting diodes (OLEDs). Because of the suppression of waveguided-mode light loss by the AR film, the resulting AR-OMO-OLED achieved an improvement of device efficiency (enhancement ratio of ~1.31) with commendable mechanical flexibility. Image 1 Highlights: Oxide-metal-oxide (OMO) transparent conducting electrode integrated with a silica nanoparticles–based antireflective (AR) film. Improvement of organic light-emitting diode (OLED) efficiency (enhancement ratio of ~1.31) based on AR-OMO electrode. Mechanical flexibility of OLEDs, retaining 100% of its initial luminance up to a bending radius of 6 mm.