Flexible lateral organic solar cells with core-shell structured organic nanofibers

One-dimensional conjugated polymer fibers provide unperturbed percolation pathways for efficient charge transport. Here, we report the fabrication of photoresponsive core-shell organic semiconductor fibers by using co-axial electrospinning and their application to the flexible organic photovoltaic devices. The electrospun organic semiconductor fibers are encapsulated with a sheath, polyvinylpyrrolidone (PVP), and consist of the photoactive materials poly(3-hexylthiophene) and phenyl-C61-butyric acid methyl ester (P3HT:PCBM). The electrospun P3HT:PCBM fibers consist of PCBM-rich core and P3HT-rich shell phases with P3HT chains aligned along the fiber direction. This structure exhibits strong photoresponsive behavior after thermal annealing, which was assessed by implementing the fibers in a phototransistor and a photodiode. Finally, we demonstrate a novel flexible photovoltaic module device on a plastic substrate that shows reliable and stable operation under bending conditions. These electrospun polymer:PCBM blend fibers are promising components for flexible optoelectric devices.