Fullerene Transformed into a 3-D Structure of Nitrogen-Doped Few-Layer Graphene Sheets: Growth and Field Emission Properties

Abstract

3-D-structured nitrogen-doped few-layer graphene sheets (3-D NFLGs) have been prepared using a fullerene C 60 precursor combined with a microwave excited nitrogen plasma process. A deep understanding of the growth mechanism and regulating of morphology that can adjust the field emission properties is crucial for its widespread application. In this work, the detailed growth process and microstructure and the field emission properties of the as-synthesized vertical aligned 3-D NFLGs were studied. The growth of the 3-D NFLGs can be divided into three steps: evaporation of the C 60 , opening of the C 60 , and formation of the 3-D NFLGs. The growth process and morphology of the materials can be neatly regulated by changing the evaporating temperature of the C 60 , electron temperature of the plasma, and substrate temperature through our self-designed reaction equipment. Interestingly, the vertical 3-D NFLGs grew at a limited microwave power and nitrogen pressure and could be divided into three different morphological features, reflected in their distribution uniformity, interparietal distance, number of layers, and crystallinity, which exhibited different field emission properties. Additionally, the 3-D NFLGs were all in situ doped with ∼4% nitrogen atoms from nitrogen gas during the growth process, while different compositions of the nitrogen atoms were reflected in the graphitic N increasing with increasing nitrogen pressure. Furthermore, the field emission measurements show that the as-obtained vertical 3-D NFLGs exhibited the lowest turn-on electric field (1.30 V/μm@10 μA/cm 2 ) and threshold field (2.1 V/μm@1 mA/cm 2 ) at the M 1 morphology and the highest stability at the M 3 morphology. Remarkable field emission performance was obtained for the 3-D NFLGs with M 2 morphology, showing their great potential for field emission applications.

A CoFe2 Alloy‐Functionalized Few‐Layer Graphene Sheet Nanocomposite as an Electrocatalyst of the Oxygen Reduction Reaction

“…Figure 1a displays a low-magnification FESEM image, revealing a well-developed lamellar graphene structure with high crystallinity and a few-layer configuration, evident from its transparent appearance. [28] Furthermore, the high-magnification FESEM image in Figure 1b illustrates the uniform embedding of CoFe 2 alloy particles within the FLGs. The TEM image in Figure 1c further confirms the uniform distribution of nanoscale CoFe 2 particles on the lamellar graphene sheets.…”

“…Firstly, the morphology and microstructure of the CoFe 2 alloy/FLGs nanocomposite were characterized using FESEM and TEM, as depicted in Figure 1. Figure 1a displays a low‐magnification FESEM image, revealing a well‐developed lamellar graphene structure with high crystallinity and a few‐layer configuration, evident from its transparent appearance [28] . Furthermore, the high‐magnification FESEM image in Figure 1b illustrates the uniform embedding of CoFe 2 alloy particles within the FLGs.…”

Field emission from sharp protrusions of graphite fabricated by sandblasting process

“…4) Carbon-based materials are particularly promising as field-emission electron source materials due to their unique shape and physical properties. [5][6][7][8][9][10][11][12] Among them, graphite is of particular interest due to its high electrical conductivity and crystallinity, and has been actively investigated as a field emitter. [13][14][15] Previous studies have reported field-emission properties from both industrial and nanoparticle graphite 13,14) as well as cone-shaped emitters fabricated from graphite using laser processing.…”