Fig. 3: Permittivity and electromagnetic wave modulation of graphene superlattice.
a Frequency-dependent permittivity of graphene superlattice. ε‘ and ε“ represent the real and imaginary part of permittivity, respectively. The vertical dashed line marks the frequency corresponding to the dielectric loss peak. b Thickness-dependent electromagnetic (EM) wave absorption efficiency of pristine bilayer graphene and graphene superlattice. Error bars represent standard deviations from three independent measurements on the same physical samples. c Comparison of EM shielding effectiveness (SET) and EM absorption efficiency (A%) averaged by EM absorbing material thickness of graphene superlattice with carbon nanotubes (CNTs) and other two-dimension (2D) materials. The data points compared in (c) are sourced from Supplementary References 82–96. d Experimental setup of graphene superlattice-based EM–electricity converter. e Open circuit voltage (Uoc) and f EM–electivity conversion of pristine graphene and graphene superlattice-based EM–electricity converter as a function of EM emission power. The EM-to-electricity conversion efficiency is defined as the ratio of power generated by a graphene device, which converts input EM energy into direct current, to the input EM power. Error bars represent standard deviations from three independent measurements on the same physical samples. g Photographs of EM–electricity conversion by graphene superlattice-based EM–electricity converter from a 5 G cell phone, a Wi-Fi router, a telecommunication tower, and a microwave (Supplementary Movies 1–4). The output DC electricity can be used to power electronic devices such as a digital hygro-thermometer and a collection of LEDs arranged in an ‘OSU’ pattern. The graphene superlattice was Te-doped.
