Carbon nanomaterial functionalized needle tip modified with low work function material and preparation method thereof

A preparation method of a carbon nanomaterial functionalized needle tip modified with a work function material, which is formed by combining a carbon nanomaterial with a material of a needle tip by means of a covalent bond, wherein when the interior of the carbon nanomaterial is modified with the work function material, wherein, the material of the needle tip is a metal which is one or more selected from tungsten, iron, cobalt, nickel, and titanium;

• the carbon nanomaterial is carbon nanocone;
• and the work function material is one or more selected from the group consisting of Ba, Ca, Yb, WC, HfC, NbC, TaC, Ni3C, LaB6, CeB6, TiN, GaN, Sr3N2, Ca@C82, Lu2C2@C82, Sc3N@C80, BaO, ZnO, and ZrO2,
• wherein the preparation method comprises:
• (1) filling the interior of the carbon nanomaterial with the work function material;
• and
• (2) assembling the carbon nanomaterial internally filled with the work function material to the tip end of the needle tip, and forming a firm interface connection between the carbon nanomaterial and the tip end of the needle tip by applying electric current or laser irradiation,
• wherein, a vacuum gas phase filling method, a melt phase filling method or a solution filling method is used to fill the interior of the carbon nanomaterial with the work function material, which comprises:
• placing a carbon nanomaterial powder in a reactor, mixing and contacting the carbon nanomaterial powder with a vapor, molten liquid or solution of a compound of the work function material, reacting for 2 to 36 hours, then washing off the work function material not filled into the carbon nanomaterial with a solvent, filtering by a suction and diving a resultant.