title: Bright light-emitting diodes based on organometal halide perovskite.
abstract: Solid-state light-emitting devices based on direct-bandgap semiconductors have, over the past two decades, been utilized as energy-efficient sources of lighting. However, fabrication of these devices typically relies on expensive high-temperature and high-vacuum processes, rendering them uneconomical for use in large-area displays. Here, we report high-brightness light-emitting diodes based on solution-processed organometal halide perovskites. We demonstrate electroluminescence in the near-infrared, green and red by tuning the halide compositions in the perovskite. In our infrared device, a thin 15 nm layer of CH3NH3PbI(3-x)Cl(x) perovskite emitter is sandwiched between larger-bandgap titanium dioxide (TiO2) and poly(9,9'-dioctylfluorene) (F8) layers, effectively confining electrons and holes in the perovskite layer for radiative recombination. We report an infrared radiance of 13.2 W sr(-1) m(-2) at a current density of 363 mA cm(-2), with highest external and internal quantum efficiencies of 0.76% and 3.4%, respectively. In our green light-emitting device with an ITO/PEDOT:PSS/CH3NH3PbBr3/F8/Ca/Ag structure, we achieved a luminance of 364 cd m(-2) at a current density of 123 mA cm(-2), giving external and internal quantum efficiencies of 0.1% and 0.4%, respectively. We show, using photoluminescence studies, that radiative bimolecular recombination is dominant at higher excitation densities. Hence, the quantum efficiencies of the perovskite light-emitting diodes increase at higher current densities. This demonstration of effective perovskite electroluminescence offers scope for developing this unique class of materials into efficient and colour-tunable light emitters for low-cost display, lighting and optical communication applications.
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Zhi-Kuang
authors.initials: ZK
authors.lastname: Tan
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Reza Saberi
authors.initials: RS
authors.lastname: Moghaddam
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: May Ling
authors.initials: ML
authors.lastname: Lai
authors.affiliation: Ludwig-Maximilians-Universität München, Butenandtstraße 11, 81377, München, Germany.
authors.forename: Pablo
authors.initials: P
authors.lastname: Docampo
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Ruben
authors.identifier: 0000000240407898
authors.initials: R
authors.lastname: Higler
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Felix
authors.initials: F
authors.lastname: Deschler
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Price
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Aditya
authors.initials: A
authors.lastname: Sadhanala
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Pazos
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Dan
authors.identifier: 0000000342462118
authors.initials: D
authors.lastname: Credgington
authors.affiliation: Ludwig-Maximilians-Universität München, Butenandtstraße 11, 81377, München, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Hanusch
authors.affiliation: Ludwig-Maximilians-Universität München, Butenandtstraße 11, 81377, München, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Bein
authors.affiliation: Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, UK.
authors.forename: Henry J
authors.initials: HJ
authors.lastname: Snaith
authors.affiliation: Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE, UK.
authors.forename: Richard H
authors.initials: RH
authors.lastname: Friend
references.citation: Nano Lett. 2013 Apr 10;13(4):1764-9
references.pmid: 23517331
references.citation: Nature. 2013 Sep 19;501(7467):395-8
references.pmid: 24025775
references.citation: Nature. 2013 Jul 18;499(7458):316-9
references.pmid: 23842493
references.citation: Sci Rep. 2012;2:591
references.pmid: 22912919
references.citation: Inorg Chem. 2013 Aug 5;52(15):9019-38
references.pmid: 23834108
references.citation: Nat Mater. 2014 May;13(5):476-80
references.pmid: 24633346
references.citation: J Am Chem Soc. 2014 Jan 22;136(3):850-3
references.pmid: 24387158
references.citation: Nano Lett. 2013 Jul 10;13(7):3124-8
references.pmid: 23772773
references.citation: Science. 2013 Oct 18;342(6156):341-4
references.pmid: 24136964
references.citation: Nano Lett. 2014 Jan 8;14(1):127-33
references.pmid: 24266720
references.citation: Science. 2002 Feb 22;295(5559):1506-8
references.pmid: 11859189
references.citation: Nat Nanotechnol. 2012 May 06;7(6):369-73
references.pmid: 22562037
references.citation: Science. 2012 Nov 2;338(6107):643-7
references.pmid: 23042296
references.citation: Science. 2013 Oct 18;342(6156):344-7
references.pmid: 24136965