SI-CHEN LEE2018-09-102018-09-102015http://www.scopus.com/inward/record.url?eid=2-s2.0-84948470755&partnerID=MN8TOARShttp://scholars.lib.ntu.edu.tw/handle/123456789/393234Two-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 QYof 0.6%, which indicates a considerable defect density. Herewe 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 finalQYofmore 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.[SDGs]SDG7molybdenum; molybdenum disulfide; quantum dot; sulfuric acid; unclassified drug; laser; luminescence; magnitude; molybdenum; optical property; photovoltaic system; physical property; technological development; Article; atomic force microscopy; Auger electron spectroscopy; circular dichroism; density; laser; light emitting diode; photoluminescence; priority journal; quantum yield; room temperature; scanning tunneling microscopy; semiconductor; X ray photoelectron spectroscopyjournal article10.1126/science.aad2114