Tuning Conductivity and Spin Dynamics in Few‐Layer Graphene via In Situ Potassium Exposure

Chemical modification such as intercalation or doping of novel materials is of great importance for exploratory material science and applications in various fields of physics and chemistry. Herein, the systematic intercalation of chemically exfoliated few‐layer graphene with potassium is reported while monitoring the sample resistance using microwave conductivity. It is found that the conductivity of the samples increases by about an order of magnitude upon potassium exposure. The increased number of charge carriers deduced from the electron spin resonance (ESR) intensity also reflects this increment. The doped phases exhibit two asymmetric Dysonian lines in ESR, a usual sign of the presence of mobile charge carriers. The width of the broader component increases with the doping steps; however, the narrow components seem to have a constant line width. The systematic intercalation of chemically exfoliated graphene with potassium is reported. The sample resistance is continuously monitored during the exposure and decreases by about an order of magnitude upon doping. The increased number of charge carriers deduced from the electron spin resonance intensity also reflects this increment. The doped phases exhibit two Dysonian lines, signaling the presence of mobile charges.