Carbon dots-derived ringent hollow carbon microspheres towards high-efficient microwave absorption.

Ringent hollow carbons synthesised by CDs through controllable reaction temperatures show great absorbing values and absorbing bands as well as relative compression ratios of radar cross section. Finite element simulation demonstrats that unique structure of ringent hollow carbons can lower normal reflected wave and promote energy attenuation which provides a new direction for the structural design of absorbers. [Display omitted] • A high-yield of carbon quantum dots derived ringent hollow carbon spheres (RHCs) for efficient microwave absorber has been proposed. • Outstanding microwave absorbing performance with optimal reflection loss of −67 dB as well as superior absorbing bandwidth (covering C, X and Ku band) could be achieved. • A relative compression ratio of 56.7 % of of RHCs loaded coating could be achieved due to ringent hollow structure and intrinsic nanosheets attenuation. Carbon nanomaterials have steadily grown into a class of composite absorbers with remarkable properties due to their unique structure, low density, high specific surface area, strong electrical conductivity, and substantial dielectric losses. In this paper, a facile strategy with low-cost, high-efficiency, and scalable strategy for carbon dots-derived ringent hollow carbon (RHC) for superior microwave absorption is proposed. Controllable structures ranging from amorphous carbon to ringent hollow carbon are well performed through simple heat-treated temperature. In addition, an optimal absorption value of −67 dB and a superior absorption band width covering the C, X, and Ku bands, as well as a relative compression ratio of 56.7 percent in the case of perpendicular incidence, have been achieved. Further, finite element simulations have demonstrated that the unique structure of partially ringent hollow carbon is considered as an effective way to lower normal reflected wave and promote energy attenuation. New applications of carbon dots-derived RHC as superior microwave absorbers are opening up, and the scalable strategy may pave a solid foundation for rapid applications. [ABSTRACT FROM AUTHOR]