Currently, flexible surfaces are becoming increasingly common in electronic devices. Electronic devices fabricated on flexible substrates are considered to have potential. Flexible supercapacitors have a long cycle life, high power density, stability, and flexibility. In this study, a flexible supercapacitor was prepared using activated carbon doped with graphene and was integrated with a flexible dye-sensitized solar cell (DSSC) to fabricate an energy conversion/storage device. A baking method was used to make the activated carbon doped with graphene powder, and a paste of this powder was deposited for use as an electrode of the supercapacitor by spin coating. A press machine was used to transfer a sintered TiO2 film from a quartz substrate to an indium tin oxide/polyethylene naphthalate (ITO/PEN) plastic substrate to fabricate a flexible DSSC. The supercapacitor doped with 0.05 wt% graphene had the highest capacitance, which was 218 F/g with a charge–discharge efficiency of 85.29%. The flexible supercapacitor maintained its capacitance well even when it was bent. A flexible DSCC integrated with a supercapacitor was fabricated to successfully power an LED.