Direct laser writing of flexible planar supercapacitors based on GO and black phosphorus quantum dot nanocomposites

The research interest in wearable electronics has continuously stimulated the development of flexible energy storage systems with high performance and robustness. However, open problems with respect to energy storage efficiency and device integration are still challenging. Here, we demonstrate the laser fabrication of flexible planar supercapacitors based on graphene oxide (GO) and black phosphorus quantum dot (BPQD) nanocomposites. By combining graphene and BPQDs, the resultant supercapacitors feature high conductivity and activity, demonstrating enhanced specific capacity and superior rate performance, compared to those based on reduced GO (RGO) alone. Furthermore, the as-obtained devices present outstanding flexibility. Their performance shows unobvious degradation after repeated cycles of bending and straightening. Additionally, with the help of direct laser writing (DLW) technology, integration of the supercapacitors has been achieved without the need for any metal interconnection. The integrated devices delivered reasonable performance uniformity with a voltage extension of 3 V, which could easily power a LED. The supercapacitor-based RGO and BPQD nanocomposites demonstrate great potential for practical applications in flexible and wearable electronics.