Large-area graphene grown by chemical vapor deposition (CVD) is a promising candidate for transparent conduc
ting electrode applications in flexible optoelectronic devices such as light-emit
ting diodes or organic solar cells. However, the power conversion efficiency (PCE) of the polymer photovoltaic devices using a pris
tine CVD graphene anode is still not appea
ling due to its much lower conductivity than that of conventional indium
tin oxide. We report a layer-by-layer molecular doping process on graphene for forming sandwiched graphene/tetracyanoquinodimethane (TCNQ)/graphene stacked films for polymer solar cell anodes, where the TCNQ molecules (as p-dopants) were securely embedded between two graphene layers. Poly(3-hexylthiophene)/phenyl-C61-butyric acid methyl ester (P3HT/PCBM) bulk heterojunction polymer solar cells based on these multilayered graphene/TCNQ anodes are fabricated and characterized. The P3HT/PCBM device with an anode structure composed of two TCNQ layers sandwiched by three CVD graphene layers shows optimum PCE (2.58%), which makes the proposed anode film quite attractive for next-generation flexible devices demanding high conductivity and transparency.
Keywords:
graphene anodes; ting+electrodes&qsSearchArea=searchText">transparent conducting electrodes; organic solar cell; organic photovoltaic cell; layer-by-layer; doping; TCNQ