A simple and effective method for the preparation of amphiphilic graphene(AG)is presented under an organic solvent-free synthetic condition.The synthetic route first involves a cyclization reaction between carboxylic groups on graphene oxide and the amino groups on 5,6-diaminopyrazine-2,3-dicarbonitrile,and subsequent reduction by hydrazine.Results of UV-vis spectroscopy,Fourier transformed infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),thermogravimetric analysis(TGA)and Raman spectroscopy have confirmed that the covalent functionalization of graphene can be achieved through the formation of imidazo[4,5-b]pyrazine on the graphene sheets.As a result,AG can be successfully dispersed in water and common organic solvents.This work successfully provides a facile and efficient way to fabricate AG and may extend the potential applications of graphene-based materials in nanoelectronic devices,polymer fillers and biological field.
We fabricated heterojunction organic field-effect transistors （OFETs） using copper phthalocyanine （CuPc） and hexadecafluorophtholocyaninatocopper （F16CuPc） as hole transport layer and electron transport layer, respectively. Compared with F 16 CuPc based OFETs, the electron field-effect mobility in the heterojunction OFETs increased from 3.1 × 10-3 to 8.7 ×10-3 cm2/（V.s）, but the p-type behavior was not observed. To enhanced the hole injection, we modified the source-lrain electrodes using the MoO3 buffer layer, and the hole injection can be effectively improved. Eventually, the ambipolar transport characteristics of the CuPc/F16CuPc based OFETs with a MoO3 buffer layer were achieved, and the field-effect mobilities of electron and hole were 2.5 × 10-3 and 3.1 × 10-3 cm2/（V.s）, respectively.
