Author(s):
Britnell, Líam 
; Ribeiro, R. M. ; Eckmann, A. ; Jalil, R. ; Belle, B. D. ; Mishchenko, A. ; Kim, Y.-J. ; Gorbachev, R. V. ; Georgiou, T. ; Morozov, S. V. ; Grigorenko, A. N. ; Geim, A. K. ; Casiraghi, C. ; Castro Neto, A. H. ; Novoselov, K. S.
Date: 2013
Persistent ID: http://hdl.handle.net/1822/24485
Origin: RepositóriUM - Universidade do Minho
Description
The isolation of various two-dimensional (2D) materials, and the possibility to combine them in vertical stacks, has created a new paradigm in materials science: heterostructures based on 2D crystals. Such a concept has already proven fruitful for a number of electronic applications in the area of ultrathin and flexible devices. Here we expand the range of such structures to photoactive ones by utilizing semiconducting transition metal dichalcogenides (TMDC)/graphene stacks. Van Hove singularities in the electronic density of states of TMDC guarantees enhanced light-matter interactions, leading to enhanced photon absorption and electron-hole creation (which are collected in transparent graphene electrodes). This allows development of extremely efficient flexible photovoltaic devices with photo-responsivity above 0.1 A/W (corresponding to an external quantum efficiency of above 30%).
