title: Surface-Engineered Graphene Quantum Dots Incorporated into Polymer Layers for High Performance Organic Photovoltaics.
abstract: Graphene quantum dots (GQDs), a newly emerging 0-dimensional graphene based material, have been widely exploited in optoelectronic devices due to their tunable optical and electronic properties depending on their functional groups. Moreover, the dispersibility of GQDs in common solvents depending on hydrophobicity or hydrophilicity can be controlled by chemical functionalization, which is particularly important for homogeneous incorporation into various polymer layers. Here we report that a surface-engineered GQD-incorporated polymer photovoltaic device shows enhanced power conversion efficiency (PCE), where the oxygen-related functionalization of GQDs enabled good dispersity in a
  PSS hole extraction layer, leading to significantly improved short circuit current density (Jsc) value. To maximize the PCE of the device, hydrophobic GQDs that are hydrothermally reduced (rGQD) were additionally incorporated in a bulk-heterojunction layer, which is found to promote a synergistic effect with the GQD-incorporated hole extraction layer.
authors.affiliation: Department of Mechanical Engineering, Stanford University, Stanford, California 94305, USA.|Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Jung Kyu
authors.initials: JK
authors.lastname: Kim
authors.affiliation: Department of Chemistry, College of Natural Sciences, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 151-747, Republic of Korea.|Soft Innovative Materials Research Center, Korea Institute of Science and Technology, Eunha-ri san 101, Bongdong-eup, Wanju-gun, Jeollabukdo, 565-905, Republic of Korea.
authors.forename: Sang Jin
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Chemistry, College of Natural Sciences, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 151-747, Republic of Korea.
authors.forename: Myung Jin
authors.initials: MJ
authors.lastname: Park
authors.affiliation: Soft Innovative Materials Research Center, Korea Institute of Science and Technology, Eunha-ri san 101, Bongdong-eup, Wanju-gun, Jeollabukdo, 565-905, Republic of Korea.
authors.forename: Sukang
authors.initials: S
authors.lastname: Bae
authors.affiliation: Department of Chemistry, College of Natural Sciences, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 151-747, Republic of Korea.
authors.forename: Sung-Pyo
authors.initials: SP
authors.lastname: Cho
authors.affiliation: Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis North, 138632, Singapore.
authors.forename: Qing Guo
authors.initials: QG
authors.lastname: Du
authors.affiliation: School of Integrative Engineering, Chung-Ang University, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756, Republic of Korea.
authors.forename: Dong Hwan
authors.initials: DH
authors.lastname: Wang
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Republic of Korea.
authors.forename: Jong Hyeok
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Chemistry, College of Natural Sciences, Seoul National University, Gwanak-ro 1, Gwanak-gu, Seoul, 151-747, Republic of Korea.
authors.forename: Byung Hee
authors.initials: BH
authors.lastname: Hong