Thermally-induced wrinkles on PH1000/graphene composite electrode for enhanced efficiency of organic solar cells

Abstract

PH1000/graphene (Gra) composite film with thermally-induced wrinkles has been employed as an electrode in organic solar cells (OSCs) to enhance the device efficiency. The wrinkled PH1000/Gra composite electrode exhibits excellent transmittance of 88.5% at 550 nm, decreased sheet resistance of 147.5 Ω sq−1 and appropriate work function of ~4.9 eV compared to pristine graphene. OSCs with wrinkled composite electrode possess enhanced short circuit current (JSC) compared to that of planar devices due to the wrinkles-induced enhancements in light absorption and charge collection. The power conversion efficiency (PCE) of OSCs with wrinkled composite electrode is 4.67%, which is 60% or 35% higher than that of planar devices based on the pristine graphene (2.93%) or PH1000 (3.45%) electrode, respectively. Corresponding PCE is comparable to that of the conventional ITO-based OSCs (5.08%). Even better, flexible OSCs with PH1000/Gra composite electrode exhibited excellent mechanical stability compared to ITO device. The enhanced efficiency of the OSCs demonstrates that the wrinkled PH1000/Gra composite electrode is a promising candidate for efficient and flexible optoelectronic application.