Solution-processable reduced graphene oxide films as broadband terahertz wave impedance matching layers

The potential of solution-processable reduced graphene oxide (rGO) films as wave impedance matching layers has been examined in a broad terahertz (THz) spectral bandwidth. The THz sheet conductivities of rGO films measured by THz time-domain spectroscopy were observed to be tunable and sensitive to the film thicknesses and reduction degrees, which can be efficiently controlled by our solution-processable fabrication method. Remarkable broadband impedance matching was achieved with a suitable rGO film, as shown by the suppression of the internal reflected THz pulses from the substrate in the spectra. The underlying mechanisms have been revealed both experimentally and theoretically. This work paves the way for developing rGO-based broadband and large-scale anti-reflection layers for THz components.