Near-unity photoluminescence quantum yield in MoS2

Patent metadata

Field	Value
Publication number	US-9852927-B2
Application number	US-201615294707-A
Country	US
Kind code	B2
Filing date	Oct 15, 2016
Priority date	Oct 16, 2015
Publication date	Dec 26, 2017
Grant date	Dec 26, 2017

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 poor. The prototypical 2D material, MoS 2 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 MoS 2 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.

First claim

What is claimed is:

1. A method of passivating and repairing a two-dimensional (2D) transition metal dichalcogenide (TMDC) to enhance a 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.

2. The method of claim 1 , wherein the 2D transition metal dichalcogenide is selected from the group consisting of MoS 2 , WS 2 , MoSe 2 , Wse 2 , MoTe 2 , and WTe 2 .

3. The method of claim 1 , further comprising dissolving 20 mg of TFSI in 10 ml of DCE to make a 2 mg/ml solution, further diluting the solution with DCB or DCE to make a 0.2 mg/ml TFSI solution, immersing the TMDC sample in the 0.2 mg/ml TFSI solution in a closed vial for between 1 min and 20 min , at an elevated temperature between 90° C. to 110 ° C., removing the TMDC sample and blow drying with nitrogen without rinsing and subsequently annealing the TMDC sample at an elevated temperature between 90° C. to 110° C. for between 1 min and 10 min.

Assignees

• Amani Matin
• Lien Der-Hsien
• Kiriya Daisuke
• Bullock James
• Javey Ali
• Univ California

Inventors

• Amani Matin
• Lien Der-Hsien
• Kiriya Daisuke
• Bullock James
• Javey Ali

Classifications

• H10P14/3436

  being chalcogenide semiconductor materials not being oxides, e.g. ternary compounds · CPC title

• H10P95/70

  Chemical treatments · CPC title

• H10P52/00

  Grinding, lapping or polishing of wafers, substrates or parts of devices · CPC title

• H10P50/20 Primary

  Dry etching; Plasma etching; Reactive-ion etching · CPC title

• C09K11/00

  Luminescent materials, e.g. electroluminescent or chemiluminescent · CPC title