skip to main content

Title: Tuning the optical emission of MoS{sub 2} nanosheets using proximal photoswitchable azobenzene molecules

We report photoluminescence measurements performed on monolayer- and two-layer-MoS{sub 2} placed on two types of mixed self-assembled monolayers (mSAMs) of photoswitchable azobenzene molecules. The two mSAMs differ via the electronegative character of the azobenzene derivatives. Thin layers of a transition metal dichalcogenide—MoS{sub 2}—were mechanically exfoliated on mSAM to allow for direct interaction between the molecules and the MoS{sub 2} layers. When the MoS{sub 2} nanosheet is in contact with the electropositive azobenzene molecules in trans configuration, an emission side band at lower energies and at low excitation powers suggest n-type doping. The photoisomerization of the molecules from trans to cis configuration lowers the doping, quenching the side band and enhancing the overall PL efficiency by a factor of ∼3. Opposite results were observed with the chlorinated, more electronegative molecules, exhibiting a reversed trend in the PL efficiency between trans and cis, but with an overall larger intensity. The type of doping induced by the two types of mSAMs was determined by Kelvin probe force microscopy technique.
Authors:
 [1] ;  [2] ; ; ; ; ; ; ;  [1] ; ;  [3] ; ;  [4]
  1. Physik Department and NIM, Walter Schottky Institute, Technische Universität München, Am Coulombwall 4, Garching D-85748 (Germany)
  2. (Germany)
  3. Dipartimento di Chimica, Università degli Studi di Milano and UdR dell'INSTM di Milano, Via Golgi 19, I-20133 Milano (Italy)
  4. Physik Department E20, Technische Universität München, James-Franck-St. 1, Garching D-85748 (Germany)
Publication Date:
OSTI Identifier:
22395520
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BENZENE; EFFICIENCY; EXCITATION; LASER RADIATION; MICROSCOPY; MOLECULES; MOLYBDENUM SULFIDES; NANOSTRUCTURES; N-TYPE CONDUCTORS; PHOTOLUMINESCENCE; PROBES; QUENCHING; SHEETS; THIN FILMS