title: Versatile p-Type Chemical Doping to Achieve Ideal Flexible Graphene Electrodes.
abstract: We report effective solution-processed chemical p-type doping of graphene using trifluoromethanesulfonic acid (CF3 SO3 H, TFMS), that can provide essential requirements to approach an ideal flexible graphene anode for practical applications: i) high optical transmittance, ii) low sheet resistance (70 % decrease), iii) high work function (0.83 eV increase), iv) smooth surface, and iv) air-stability at the same time. The TFMS-doped graphene formed nearly ohmic contact with a conventional organic hole transporting layer, and a green phosphorescent organic light-emitting diode with the TFMS-doped graphene anode showed lower operating voltage, and higher device efficiencies (104.1 cd A(-1) , 80.7 lm W(-1) ) than those with conventional ITO (84.8 cd A(-1) , 73.8 lm W(-1) ).
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Nam-gu, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Tae-Hee
authors.initials: TH
authors.lastname: Han
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Nam-gu, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Sung-Joo
authors.initials: SJ
authors.lastname: Kwon
authors.affiliation: Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Nannan
authors.initials: N
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Nam-gu, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Hong-Kyu
authors.initials: HK
authors.lastname: Seo
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Nam-gu, Pohang, Gyungbuk, 790-784, Republic of Korea.
authors.forename: Wentao
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Chemistry, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Republic of Korea.
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Nam-gu, Pohang, Gyungbuk, 790-784, Republic of Korea. twlee@postech.ac.kr.
authors.forename: Tae-Woo
authors.initials: TW
authors.lastname: Lee
keywords: chemical doping; flexible OLEDs; graphene; transparent electrodes