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Physicochemical properties of hybrid graphene–lead sulfide quantum dots prepared by supercritical ethanol

Tavakoli, M. M ; Sharif University of Technology | 2015

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  1. Type of Document: Article
  2. DOI: 10.1007/s11051-014-2854-8
  3. Publisher: Kluwer Academic Publishers , 2015
  4. Abstract:
  5. Recently, hybrid graphene–quantum dot systems have attracted increasing attention for the next-generation optoelectronic devices such as ultrafast photo-detectors and solar energy harvesting. In this paper, a novel, one-step, reproducible, and solution-processed method is introduced to prepare hybrid graphene–PbS colloids by employing supercritical ethanol. In the hybrid nanocomposite, PbS quantum dots (~3 nm) are decorated on the reduced graphene oxide (rGO) nanosheets (~1 nm thickness and less than 1 micron lengths). By employing X-ray photoelectron and Raman and infrared spectroscopy techniques, it is shown that the rGO nanosheets are bonded to PbS nanocrystals through carboxylic bonds. Passivation of {111} planes of PbS quantum dots with rGO nanosheets is demonstrated by employing density function theory. Quenching of the photoluminescence emission of PbS nanocrystals through coupling with graphene sheets is also shown. In order to illustrate that the developed preparation method does not impair the quantum efficiency of the PbS nanocrystals, the photovoltaic efficiency of solar cell device is reported and compared with oleic acid-capped PbS colloidal quantum dot solar cells. By employing the “Hall effect” measurement, it is shown that the carrier mobility is significantly increased (by two orders of magnitudes) in the presence of graphene nanosheets
  6. Keywords:
  7. Photovoltaic ; Reduced graphene oxide ; Carrier mobility ; Ethanol ; Graphene ; Hall mobility ; Infrared spectroscopy ; Nanocrystals ; Nanosheets ; Optoelectronic devices ; Semiconducting lead compounds ; Semiconductor quantum dots ; Solar cells ; Solar energy ; Solar power generation ; Density function theory ; Lead sulfide ; Quantum efficiency ; Alcohol ; Graphene lead sulfide quantum dot ; Graphene oxide ; Graphene oxide nanosheet ; Nanocomposite ; Quantum dot ; Unclassified drug ; Chemical bond ; Infrared spectroscopy ; Photoluminescence ; Physical chemistry ; Priority journal ; Raman spectrometry ; Supercritical fluid ; Thickness ; X ray photoelectron spectroscopy
  8. Source: Journal of Nanoparticle Research ; Volume 17, Issue 1 , January , 2015 ; 13880764 (ISSN)
  9. URL: http://link.springer.com/article/10.1007%2Fs11051-014-2854-8