Near-unity photoluminescence quantum yield in MoS2

By M. Amani, D. Lien, D. Kiriya, Jun Xiao, A. Azcatl, Jiyoung Noh, S. Madhvapathy, R. Addou, S. Kc, Madan Dubey and 8 more. Science, 2015

907 citations recorded by the source corpus.

Brighter molybdenum layers The confined layers of molybdenum disulphide (MoS2) exhibit photoluminescence that is attractive for optolectronic applications. In practice, efficiencies are low, presumably because defects trap excitons before they can recombine and radiate light. Amani et al. show that treatment of monolayer MoS2 with a nonoxidizing organic superacid, bis(trifluoromethane) sulfonimide, increased luminescence efficiency in excess of 95%. The enhancement mechanism may be related to the shielding of defects, such as sulfur vacancies. Science, this issue p. 1065 Superacid treatment enhances the luminescence efficiency of monolayer molybdenum disulfide from 1% to >95%. 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.

Subfields: Materials Chemistry

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Citations in the corpus

2D semiconducting materials for electronic and optoelectronic applications: potential and challenge (2020, methodology): “To eliminate the intrinsic defects of TMDCs and improve their optical and electrical properties, various chemical surface treatments have been utilized [89, 103].”
Mixed-dimensional van der Waals heterostructures. (2016, background): “Towards this end, advances in surface passivation and encapsulation to minimize non-radiative recombination are the necessary first steps.(135) Unlike photovoltaic cells and photodetectors, light-emitting devices will require active layer architectures that maximize the interaction of minority carri”
Excitons in atomically thin 2D semiconductors and their applications (2017, background): “In MoS2, the PL quantum yield can even approach 100%, with the assistance of chemical treatments [12].”
Optical properties of atomically thin transition metal dichalcogenides: observations and puzzles (2016, background): “[49] for efforts to improve the quality of MoS2 optical response).”
Progress in Contact, Doping and Mobility Engineering of MoS2: An Atomically Thin 2D Semiconductor (2018, methodology): “using an air-stable, solution-based chemical treatment by an organic superacid, namely, bis(trifluoromethane) sulfonamide or TFSI, resulting in a near-unity photoluminescence (PL) yield and minority carrier lifetime enhancement, showing great promise for MoS2-based optoelectronic devices [297].”
Micro-reflectance and transmittance spectroscopy: a versatile and powerful tool to characterize 2D materials (2016, methodology): “Although suggestions were made in the literature for the improvement of optical properties for ML materials by chemical treatment [58] and for mechanically stacked systems [59], a decisive comparison requires untreated samples to be investigated, which were fabricated under similar circumstances usi”