Induced Room-Temperature Ferromagnetism in Graphdiyne by a Synergistic Effect of Out-of-Plane F and OH Dual-Doping

Graphdiyne (GDY), a novel two-dimensional (2D) carbon allotrope featuring sp- and sp2-hybridized carbon, boasts high electron mobility and an intrinsic direct band gap, making it a promising candidate for spin-based semiconductor device applications. However, its inherent nonmagnetism limits its potential in this area. In this study, we demonstrate that dual-doping GDY with fluorine (F) and hydroxyl (OH) groups can induce room-temperature (RT) ferromagnetism, the intensity of which can be modulated by adjusting the levels of F and OH dual-doping. Our experimental results and theoretical analyses reveal several key findings: (i) both dopants preferentially adsorb onto the chain structure of GDY, leading to local magnetic moments; (ii) OH groups deter clustering of F adatoms, thus enhancing magnetic-inducing efficiency; and (iii) these magnetic moments are coupled through superexchange interactions between magnetic 1,2,3-trimethylbenzene motifs. This carefully devised strategy not only facilitates the realization of RT ferromagnetic GDY but also paves the way for the development of GDY-based spintronic devices. This advancement could potentially broaden the scope of applications for this unique 2D material.