Transparent brush-type carbon nanotube cathode

Here we report brush-type carbon nanotubes (BCNT) film, which is combined with graphene and carbon nanotube (CNT) array, as cathode on transparent substrate. Prepared by pyrolysis, vertically aligned CNT (VACNT) arrays are covered by a few layer graphene sheets like thin blankets. There are both good electrical and mechanical connections between VACNT arrays and graphene sheets. Transparent field emission cathode is built by transferring the BCNT film upside down to glass substrate. Taking BCNT roots as field emitters, we found that they have lower threshold field, higher emission current and better luminescence uniformity than that of as-grown VACNT emitters. BCNT film could improve electron transport properties from CNT emitters to substrate with the help of a few layer graphene sheets. BCNT films have a promising future in flexible devices.