• 文献标题:   Pushing the conductance and transparency limit of monolayer graphene electrodes for flexible organic light-emitting diodes
  • 文献类型:   Article
  • 作  者:   MA LP, WU ZB, YIN LC, ZHANG DD, DONG SC, ZHANG Q, CHEN ML, MA W, ZHANG ZB, DU JH, SUN DM, LIU KH, DUAN XF, MA DG, CHENG HM, REN WC
  • 作者关键词:   flexible optoelectronic, graphene, transparent electrode, doping, antireflection
  • 出版物名称:   PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
  • ISSN:   0027-8424
  • 通讯作者地址:   Chinese Acad Sci
  • 被引频次:   0
  • DOI:   10.1073/pnas.1922521117
  • 出版年:   2020

▎ 摘  要

Graphene has emerged as an attractive candidate for flexible transparent electrode (FTE) for a new generation of flexible optoelectronics. Despite tremendous potential and broad earlier interest, the promise of graphene FTE has been plagued by the intrinsic trade-off between electrical conductance and transparency with a figure of merit (sigma(DC)/sigma(Op)) considerably lower than that of the state-of-the-art ITO electrodes (sigma(DC)/sigma(Op) <123 for graphene vs. similar to 240 for ITO). Here we report a synergistic electrical/optical modulation strategy to simultaneously boost the conductance and transparency. We show that a tetrakis(pentafluorophenyl)boric acid (HTB) coating can function as highly effective hole doping layer to increase the conductance of monolayer graphene by sevenfold and at the same time as an antireflective layer to boost the visible transmittance to 98.8%. Such simultaneous improvement in conductance and transparency breaks previous limit in graphene FTEs and yields an unprecedented figure of merit (sigma(DC)/sigma(Op) similar to 323) that rivals the best commercial ITO electrode. Using the tailored monolayer graphene as the flexible anode, we further demonstrate high-performance green organic light-emitting diodes (OLEDs) with the maximum current, power and external quantum efficiencies (111.4 cd A(-1), 124.9 lm W-1 and 29.7%) outperforming all comparable flexible OLEDs and surpassing that with standard rigid ITO by 43%. This study defines a straight-forward pathway to tailor optoelectronic properties of monolayer graphene and to fully capture their potential as a generational FTE for flexible optoelectronics.