Design and synthesis of hydrogenated carbon nanomaterials for perovskite solar cells

Carbon nanomaterials have emerged as promising alternatives to noble metals in perovskite solar cells (PSCs) due to their excellent electrical properties, chemical stability, and scalability. Tailoring hydrogen incorporation during synthesis enables precise modification of the electronic structure and surface chemistry, thereby enhancing charge transport and improving the electrode/perovskite interface quality. Here, we report the synthesis of hydrogenated carbon nanosheets via a solid-gas reaction at various temperatures and times, achieving controllable H content and tunable electrical conductivity as well as sheet resistance. As the heating temperature increases, carbon content increases. In contrast, H content decreases, leading to enhanced electrical conductivity (e.g., a sheet resistance of 452 and 91 ohm sq^-1 for 400C-12h and 500C-12h samples, respectively) and decreased disorder bands in Raman spectroscopy. XRD, SEM and BET analysis confirmed an amorphous carbon with a mesoporous architecture and high surface area (245 m² g^-1 for 500C-12h). Using the 500C-12h sample as the electrode, PSCs achieved the highest power conversion efficiency of 16.54%, outperforming devices with commercial carbons. Furthermore, hybrid carbon electrodes (7 : 3 hydrogenated carbon : carbon black) improved both J_sc and V_oc values, leading to a PCE of 18.21%, as well as long-term stability up to 1000 h. These findings position hydrogenated carbon, in pure or hybrid form, as a scalable, cost-effective, and durable alternative to noble-metal electrodes for next-generation PSCs.