▎ 摘　　要

We report a large scale root to assemble hierarchical copper-based nanostructures on nitrogen-doped graphene sheets by a pH followed by a temperature-directed self-assembly process and their electron field emission studies. Starting with a controlled pH directed self-assembly root, we assembled Cu(OH)(2) NRs on NGS and further reassembled it to 1D Cu NPAs and CuO NRs by thermal annealing in H-2 and Ar atmosphere, respectively. The field emission characteristics are precisely studied, which depicts a significantly lower threshold and turn-on field for 1D Cu NPAs-NGS-based emitter compared to CuO NRs-NGS and Cu(OH)(2) NRs-NGS. Also it exhibited about 3 and 27 times higher emission current density than its oxide and hydroxide counterpart under a moderate field of 1 V/mu m. The enhanced field emission behavior of 1D Cu NPAs-NGS is attributed to the low work function, the easy electron tunneling from the one-dimensional arrangement of Cu NPs, which increases the emission sites and hence the FE current density. On the basis of easy large-scale synthesis techniques and better FE performances, these hierarchical nanostructures offer prospects for understanding the effect of linear arrangement of nanoparticles on FE, which can be envisioned for design, fabrication, and optimization of cold cathode devices.