Preparation of N, P co-doped flake-like carbon materials and their application in counter electrodes of dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) are highly valued for their simple manufacturing process and environmental friendliness, but the commonly used counter electrode material (Pt) has excellent electrochemical performance yet suffers from high cost and insufficient stability. This study uses phytic acid (a biomass-derived carbon/phosphorus source) and melamine (a nitrogen source) as precursors to prepare nitrogen and phosphorus co-doped flake-like carbon materials (NP@C-900) via a hydrothermal co-doping strategy to replace platinum. After high-temperature carbonization, the phosphorus elements from phytic acid and nitrogen elements from melamine are co-introduced into the carbon material to form active sites, thereby enhancing its electrochemical performance. Relying on the excellent intrinsic stability of the carbon material itself, it achieves both satisfactory electrochemical performance and outstanding electrochemical stability. In the photoelectric conversion efficiency test, the DSSCs assembled with NP@C-900 counter electrodes achieve a photoelectric conversion efficiency (PCE) of 8.79%, surpassing the level of platinum electrodes (8.64%). In the subsequent stability tests, the stability of DSSCs based on carbon electrodes also exceeds that of platinum-based electrodes. This study provides a new strategy for developing low-cost, high-performance counter electrodes for DSSCs.