Novel microwave absorbers based on polypyrrole and carbon quantum dots

Abstract

Herein, polypyrrole/carbon quantum dots (PPyCQDs) composite microwave absorbers (MA) were prepared via in-situ polymerization of pyrrole in presence of CQDs. The structural, morphological and electrical characterization of the samples were performed using X-Ray diffractometry, infra-red spectroscopy, UV–vis spectroscopy, AFM, SEM and DC conductivity measurements. Microwave absorbing properties were investigated by measuring the reflection loss (RL) within the range of 2–8 GHz as a function of thickness and loading percentage. Results revealed an increase in DC conductivity and RL in parallel with CQDs content increase. The minimum reflection loss was −27.82 dB at 6.93 GHz for a matching thickness of 3.25 mm. The bandwidth under −10dB was 2.34 GHz for a loading percentage of 25% in a host matrix of paraffin. The use of CQDs in the preparation of MA has not been reported before, and the current microwave absorber holds great promise for the design of new generations of microwave absorbers.