Nitrogen doping is a promising approach to induce the basal-plane localized magnetic moments in $\mathit{sp}$-electron-only graphene sheets. Enhancing the magnetic couplings among the moments can contribute to the high Curie temperature $T_C$ and large ratio of ferromagnetism (FM), which is vital for real applications in spintronic devices; however, it is still challenging. Here, we experimentally demonstrate that graphitic nitrogen (N-Q) could enhance the ferromagnetic couplings of localized magnetic moments provided by the defective N in nitrogen-doped graphene (NG). Nearly pure FM at 2 K is obtained in ${\mathrm{NG}}_{16.04}$ (N-Q/N = 16.04 at. %) with a $T_C$ up to 397.5 K, while the room-temperature saturated magnetization is high as $\sim 0.4$ emu/g. The rich $\mathrm{C}\to \mathrm{N}$ electrons contributed by the high ratio of the N-Q complex dominantly devote itinerant magnetism and enhance the interactions among the pyrrolic N (N-5) and/or pyridinic N complexes. Our density functional theory simulation results provide the configurations of (trimerized N-5)-triazinic N-Q along certain directions with enhanced sublattice-independent FM, which are proposed to be the magnetic structures in ${\mathrm{NG}}_{16.04}$. Our investigation reveals that introducing the N-Q can serve as an ideal route for the long-range spin correlations and thus full ferromagnetic couplings in graphene.

Flexible pressure sensors play an important role in flexible robotics, human-machine interaction (HMI), and human physiological information. However, most of the reported flexible pressure sensors suffer from a highly nonlinear response and a significant decrease in sensitivity at high pressures. Herein, we propose a flexible novel iontronic pressure sensor based on monolayer molybdenum disulfide (MoS₂). Based on the unique structure and the excellent mechanical properties as well as the large intercalation capacitance of MoS₂, the prepared sensor holds an ultra-high sensitivity (S_max = 89.75 kPa⁻¹) and a wide sensing range (722.2 kPa). Further, the response time and relaxation time of the flexible sensor are only 3 ms, respectively, indicating that the device can respond to external pressure rapidly. In addition, it shows long-term cycling stability (over 5000 cycles with almost no degradation) at a high pressure of 138.9 kPa. Finally, it is demonstrated that the sensor can be used in physiological information monitoring and flexible robotics. It is anticipated that our prepared sensor provide a reliable approach to advance the theory and practicality of the flexible sensor electronics.