“…Recently, the cell performance of OPVs was sharply increased up to 8-12% with changing the various parameters (open circuit voltage (V oc ), current density (J sc ), fill factor (FF) and resistance, etc.) (Park et al, 2010;Zhang et al, 2010;Li et al, 2012;Kim et al, 2013Kim et al, , 2014. In order to get the high PCE of OPVs, it is important to decrease the resistance between the buffer layer and active layer because http://dx.doi.org/10.1016/j.solener.2015.07.047 0038-092X/Ó 2015 Elsevier Ltd. All rights reserved.…”