Controllable fabrication of novel graphene quantum dots/fluorinated boron nitride ultralight composites for broadband and high-performance microwave absorption. (January 2022) - Hu, Qi
Abstract: The microwave absorption performance of graphene materials is severely hindered by their high dielectric constant and ultralow magnetic loss ability. Herein, for the first time, we report a simple strategy to achieve a suitable electromagnetic match by fabricating fluorinated boron nitride nanosheets supported graphene quantum dots (GQDs/F-BNNs) composites. Our results show that the reduced microwave reflection and enhanced magnetic loss are attributed to the low dielectric constant and ferromagnetism of F-BNNs, which also overcome the typically hydrophilic of GQDs to realize desirable stability in water. Then, we highlight that the absorption bandwidths and reflection loss ( RL min ) are closely correlated with the size of GQDs, which is introduced by the modulated bandgap widths of GQDs concerning microwave in different frequencies. Thereinto, the optimized GQDs/F-BNNs exhibit excellent microwave absorption performance with the RL min of −66.69 dB with a thin thickness of only 5.29 mm in 2∼18 GHz. Moreover, when the frequency reaches 19∼26 dB and 27∼40 dB, RL values are also both less than −10 dB. Our findings pave the way for GQDs and pioneer F-BNNs as lightweight and high-efficient microwave absorbing materials. Graphical abstract: Image 1