Fast Charge Transfer Confers New Skills on 3D Graphene Sponges: Human Body Induction and Infrared Radiation Induction

Abstract Three‐dimensional graphene sponge (3DG), a bulk collection of numerous suspended individual graphene sheets, could demonstrate an integrated response thousands of times stronger than that of a single sheet under applied external field induction. Herein, for the first time, we find that a two‐electrode system assembled with 3DG monoliths shows a high sensitivity to human body induction and infrared radiation. The induced open circuit voltage of the two‐electrode system increases by 900 mV in a hand approaching‐departing induction. In a closed circuit, fluctuating current is observed flowing backward and forward from one 3DG electrode to another, and it decreased obviously when 3DG electrodes were exposed to infrared radiation. This high sensitivity to electrostatic/infrared radiation induction is attributed to the high‐speed electron redistribution capability of 3DG materials under an applied external electric field or light radiation. These results make 3DG a promising smart material in applications including intelligent monitoring, human body sensors, military protection and life detectors.