title: Highly efficient polymer-based optoelectronic devices using PEDOT:PSS and a GO composite layer as a hole transport layer.
abstract: We demonstrate highly efficient polymer light-emitting diodes (PLEDs), as well as polymer solar cells (PSCs), using a solution-processable poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS):graphene oxide (GO) (PEDOT:GO) composite layer as hole transport layers (HTLs). The PEDOT:GO composite HTL layer shows enhanced charge carrier transport due to improved conductivity by benzoid-quinoid transitions with a well-matched work function between GO (4.89 eV) and PEDOT:PSS (4.95 eV). Moreover, it reduces remarkably exciton quenching and suppresses recombinations that bring higher charge extraction in PSCs and increases the recombinations of holes and electrons within the active layer by the blocking behavior of the electrons from a fluorescent semiconductor due to the existence of GO with large bandgap (∼3.6 eV) in the PEDOT:GO composite layer, therefore leading to an enhancement of device efficiency in PLEDs and PSCs. The optimized PLEDs and PSCs with a PEDOT:GO composite HTL layer shows the maximum luminous efficiency of 21.74 cd/A (at 6.4 V) for PLEDs, as well as the power conversion efficiency of 8.21% for PSCs, which were improved by ∼220 and 12%, respectively, compared to reference PLEDs and PSCs with a PEDOT:PSS layer.
authors.affiliation: School of Materials Science Engineering, ‡KIST-UNIST Ulsan Center for Convergent Materials Center, and §Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST) , UNIST-gil 50, Ulsan 689-798, Republic of Korea.
authors.forename: Jae Choul
authors.initials: JC
authors.lastname: Yu
authors.forename: Jeong In
authors.initials: JI
authors.lastname: Jang
authors.forename: Bo Ram
authors.initials: BR
authors.lastname: Lee
authors.forename: Geon-Woong
authors.initials: GW
authors.lastname: Lee
authors.forename: Joong Tark
authors.initials: JT
authors.lastname: Han
authors.forename: Myoung Hoon
authors.initials: MH
authors.lastname: Song