Outcoupling-enhanced flexible organic light-emitting diodes on ameliorated plastic substrate with built-in indium-tin-oxide-free transparent electrode

Heng-Yang Xiang, Yan-Qing Li, Lei Zhou, Hao-Jun Xie, Chi Li, Qing-Dong Ou, Lin-Sen Chen, Chun-Sing Lee, Shuit-Tong Lee, Jian-Xin Tang

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79 Citations (Scopus)


Enhancing light outcoupling in flexible organic light-emitting diodes (FOLEDs) is an important task for increasing their efficiencies for display and lighting applications. Here, a strategy for an angularly and spectrally independent boost in light outcoupling of FOLEDs is demonstrated by using plastic substrates with a low refractive index, consisting of a bioinspired optical coupling layer and a transparent conductive electrode composed of a silver network. The good transmittance to full-color emission (>94% over the whole visible wavelength range), ultralow sheet resistance to carrier injection (<5 Ω sq-1), and high tolerance to mechanical bending of the ameliorated plastic substrates synergistically optimize the device performance of FOLEDs. The maximum power efficiencies reach 47, 93, 56, and 52 lm W-1 for red, green, blue, and white emissions, which are competitive with similarly structured OLEDs fabricated on traditional indium-tin-oxide (ITO) glass. This paradigm for light outcoupling enhancement in ITO-free FOLEDs offers additional features and design freedoms for highly efficient flexible optoelectronics in large-scale and low-cost manufacturing without the need for a high-refractive-index plastic substrate.

Original languageEnglish
Pages (from-to)7553-7562
Number of pages10
JournalACS Nano
Issue number7
Publication statusPublished - 28 Jul 2015


  • flexible OLEDs
  • flexible transparent conductors
  • light outcoupling
  • plastic substrates

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