Loading...

Quasi core/shell lead sulfide/graphene quantum dots for bulk heterojunction solar cells

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

1392 Viewed
  1. Type of Document: Article
  2. DOI: 10.1021/acs.jpcc.5b04195
  3. Publisher: American Chemical Society , 2015
  4. Abstract:
  5. Hybrid nanostructures combining semiconductor quantum dots and graphene are attracting increasing attention because of their optoelectronic properties promising for photovoltaic applications. We present a hot-injection synthesis of a colloidal nanostructure which we define as quasi core/shell PbS/graphene quantum dots due to the incomplete passivation of PbS surfaces with an ultrathin layer of graphene. Simulation by density functional theory of a prototypical model of a nonstoichiometric Pb-rich core (400 atoms) coated by graphene (20 atoms for each graphene sheet) indicates the possibility of surface passivation of (111) planes of PbS with graphene resulting in a decrease in trap states and recombination sites. The graphene coating of the PbS quantum dots decreases the exciton lifetime up to 0.78 μs as compared to 1.2 μs for the oleic acid passivated PbS quantum dots due to the fast extraction of carriers. We have employed PbS/graphene as well as Cd-doped PbS/graphene quantum dots as active layers of bulk heterojunction solar cells, and we achieved solar power conversion efficiencies of 3.6 and 4.1%, respectively
  6. Keywords:
  7. Density functional theory ; Graphene ; Heterojunctions ; Lead ; Nanocrystals ; Nanostructures ; Passivation ; Semiconducting lead compounds ; Solar cells ; Solar energy ; Bulk heterojunction solar cells ; Graphene coatings ; Hybrid nanostructures ; Non-stoichiometric ; Optoelectronic properties ; Photovoltaic applications ; Solar power conversion ; Surface passivation ; Semiconductor quantum dots
  8. Source: Journal of Physical Chemistry C ; Volume 119, Issue 33 , 2015 , Pages 18886-18895 ; 19327447 (ISSN)
  9. URL: http://pubs.acs.org/doi/abs/10.1021/acs.jpcc.5b04195