▎ 摘　　要

The electronic properties and spin magnetism of graphene nanoribbon doped with triangular BN flake are systematically investigated. For the spin polarized state, the size of the triangular BN flake could tailor the spin magnetism of devices. More importantly, it will intrigue property of bipolar magnetic semiconducting with the spin-filtering efficiency (SFE) nearly reaching 100% and keep good transport property when the triangular BN flake is large enough. Although the triangular vacancies also present a bipolar magnetic semiconducting property with a higher SFE, the transmission probability drops dramatically and the stability is no more than those of triangle BN flake.