Graphene transparent conductive electrodes doped with graphene quantum dots-mixed silver nanowires for highly-flexible organic solar cells

Recent active studies on flexible photovoltaic cells strongly call for matchable flexible transparent electrodes. Graphene (GR) is one of the promising candidates as transparent conductive electrodes (TCEs) for flexible photovoltaic cells, but high sheet resistance of GR limits the efficiency of the cells. Here, we first fabricate GR TCEs doped with graphene quantum dots (GQDs)-mixed silver nanowires (Ag NWs) on polyethylene terephthalate substrates for highly-flexible organic solar cells (OSCs). With increasing doping concentration of GQDs to 0.03 g/L, the sheet resistance of the Ag NWs/GR TCE decreases to ∼92 Ω/sq whilst its work function increases to ∼4.53 eV, resulting in 3.66% power-conversion efficiency (PCE). In addition, the GQDs enhance the bending flexibility of the Ag NWs/GR TCEs, thereby maintaining the initial PCE of the OSCs over 90% even after 1000 bending cycles at a curvature radius of 4 mm.