title: Near-unity photoluminescence quantum yield in MoS₂.
abstract: Two-dimensional (2D) transition metal dichalcogenides have emerged as a promising material system for optoelectronic applications, but their primary figure of merit, the room-temperature photoluminescence quantum yield (QY), is extremely low. The prototypical 2D material molybdenum disulfide (MoS2) is reported to have a maximum QY of 0.6%, which indicates a considerable defect density. Here we report on an air-stable, solution-based chemical treatment by an organic superacid, which uniformly enhances the photoluminescence and minority carrier lifetime of MoS2 monolayers by more than two orders of magnitude. The treatment eliminates defect-mediated nonradiative recombination, thus resulting in a final QY of more than 95%, with a longest-observed lifetime of 10.8 ± 0.6 nanoseconds. Our ability to obtain optoelectronic monolayers with near-perfect properties opens the door for the development of highly efficient light-emitting diodes, lasers, and solar cells based on 2D materials.
authors.affiliation: Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Matin
authors.initials: M
authors.lastname: Amani
authors.affiliation: Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia. Department of Electrical Engineering, Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
authors.forename: Der-Hsien
authors.initials: DH
authors.lastname: Lien
authors.affiliation: Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kiriya
authors.affiliation: National Science Foundation Nanoscale Science and Engineering Center, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Xiao
authors.affiliation: Department of Materials Science and Engineering, University of Texas, Dallas, Richardson, TX 75080, USA.
authors.forename: Angelica
authors.initials: A
authors.lastname: Azcatl
authors.affiliation: Department of Materials Science and Engineering, University of Texas, Dallas, Richardson, TX 75080, USA.
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Noh
authors.affiliation: Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Surabhi R
authors.initials: SR
authors.lastname: Madhvapathy
authors.affiliation: Department of Materials Science and Engineering, University of Texas, Dallas, Richardson, TX 75080, USA.
authors.forename: Rafik
authors.initials: R
authors.lastname: Addou
authors.affiliation: Department of Materials Science and Engineering, University of Texas, Dallas, Richardson, TX 75080, USA.
authors.forename: Santosh
authors.initials: S
authors.lastname: KC
authors.affiliation: Sensors and Electron Devices Directorate, U.S. Army Research Laboratory, Adelphi, MD 20723, USA.
authors.forename: Madan
authors.initials: M
authors.lastname: Dubey
authors.affiliation: Department of Materials Science and Engineering, University of Texas, Dallas, Richardson, TX 75080, USA.
authors.forename: Kyeongjae
authors.initials: K
authors.lastname: Cho
authors.affiliation: Department of Materials Science and Engineering, University of Texas, Dallas, Richardson, TX 75080, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Wallace
authors.affiliation: Department of Electrical Engineering, Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan, Republic of China.
authors.forename: Si-Chen
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Computer, Electrical and Mathematical Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia.
authors.forename: Jr-Hau
authors.initials: JH
authors.lastname: He
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Joel W
authors.initials: JW
authors.lastname: Ager
authors.affiliation: National Science Foundation Nanoscale Science and Engineering Center, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Department of Physics, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
authors.forename: Xiang
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
authors.forename: Eli
authors.initials: E
authors.lastname: Yablonovitch
authors.affiliation: Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA 94720, USA. Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. ajavey@eecs.berkeley.edu.
authors.forename: Ali
authors.initials: A
authors.lastname: Javey