title: Overcoming the electroluminescence efficiency limitations of perovskite light-emitting diodes.
abstract: Organic-inorganic hybrid perovskites are emerging low-cost emitters with very high color purity, but their low luminescent efficiency is a critical drawback. We boosted the current efficiency (CE) of perovskite light-emitting diodes with a simple bilayer structure to 42.9 candela per ampere, similar to the CE of phosphorescent organic light-emitting diodes, with two modifications: We prevented the formation of metallic lead (Pb) atoms that cause strong exciton quenching through a small increase in methylammonium bromide (MABr) molar proportion, and we spatially confined the exciton in uniform MAPbBr3 nanograins (average diameter = 99.7 nanometers) formed by a nanocrystal pinning process and concomitant reduction of exciton diffusion length to 67 nanometers. These changes caused substantial increases in steady-state photoluminescence intensity and efficiency of MAPbBr3 nanograin layers.
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyungbuk 790-784, Republic of Korea.
authors.forename: Himchan
authors.initials: H
authors.lastname: Cho
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyungbuk 790-784, Republic of Korea.
authors.forename: Su-Hun
authors.initials: SH
authors.lastname: Jeong
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyungbuk 790-784, Republic of Korea.
authors.forename: Min-Ho
authors.initials: MH
authors.lastname: Park
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyungbuk 790-784, Republic of Korea.
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyungbuk 790-784, Republic of Korea.
authors.forename: Christoph
authors.initials: C
authors.lastname: Wolf
authors.affiliation: Advanced Photonics Research Institute (APRI), Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712, Republic of Korea.
authors.forename: Chang-Lyoul
authors.initials: CL
authors.lastname: Lee
authors.affiliation: Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1 Seochon-dong, Giheung-gu, Youngin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Jin Hyuck
authors.initials: JH
authors.lastname: Heo
authors.affiliation: Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Aditya
authors.initials: A
authors.lastname: Sadhanala
authors.affiliation: Advanced Photonics Research Institute (APRI), Gwangju Institute of Science and Technology (GIST), 1 Oryong-dong, Buk-gu, Gwangju 500-712, Republic of Korea.
authors.forename: NoSoung
authors.initials: N
authors.lastname: Myoung
authors.affiliation: Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea.
authors.forename: Seunghyup
authors.initials: S
authors.lastname: Yoo
authors.affiliation: Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1 Seochon-dong, Giheung-gu, Youngin-si, Gyeonggi-do 446-701, Republic of Korea.
authors.forename: Sang Hyuk
authors.initials: SH
authors.lastname: Im
authors.affiliation: Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend
authors.affiliation: Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Pohang, Gyungbuk 790-784, Republic of Korea. Department of Chemical Engineering, Division of Advanced Materials Science, School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-Ro, Nam-Gu, Pohang, Gyungbuk 790-784, Republic of Korea. twlee@postech.ac.kr taewlees@gmail.com.
authors.forename: Tae-Woo
authors.initials: TW
authors.lastname: Lee