Intrinsic negative TCR of superblack carbon aerogel films and their ultrabroad band response from UV to microwave

Hot-electron effect in the superblack carbon aerogel (CA) may lead to the relatively strong response to long-wavelength electromagnetic wave by comparison with the ohmic loss effect. In this article, we find a negative temperature coefficient of resistance (TCR) with a value of about 0.13-0.15%/K in superblack CA films. Interestingly, the negative TCR is the intrinsic nature of the amorphous CA films, which mainly attributes to the increase of carrier concentration according to the Hall Effect results. The behavior is just similar to a combination of graphite and carbon quantum dots. At last, the CA film with a thickness of about 400 nm was used and exhibited ultrabroad band response from UV light, visible light, infrared ray to microwave, owing to the strong absorption and the high-efficiency photo-thermal conversion induced by hot electrons. The intrinsic properties of superblack CA films may provide a novel route to low-cost and high-efficiency longwave detection. (C) 2020 Elsevier Ltd. All rights reserved.