Near-Unity Photoluminescence Quantum Yield in MoS2

摘要

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 poor. The prototypical 2D material, MoS2 is reported to have a maximum QY of 0.6% which indicates a considerable defect density. 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 over two orders of magnitude. The treatment eliminates defect-mediated non-radiative recombination, thus resulting in a final QY of over 95% with a longest observed lifetime of 10.8±0.6 nanoseconds. Obtaining perfect optoelectronic monolayers opens the door for highly efficient light emitting diodes, lasers, and solar cells based on 2D materials.

主权项

1. A method of passivating and repairing a 2D transition metal dichalcogenide (TMDC) to enhance the photoluminescence quantum yield (QY) comprising:
dissolving bis(trifluoromethane)sulfonimide (TFSI) in 1,2-dichloroethane (DCE) to make a solution; diluting the solution with 1,2-dichlorobenzene (DCB) or DCE to make a TFSI solution; immersing a TMDC sample in the TFSI solution; and annealing the TMDC sample at an elevated temperature.