Deep‐Ultraviolet Electro‐optic Modulator Based on Fluorographene Liquid Crystal

ABSTRACT Graphene‐based liquid crystals have ultra‐high electric responsivity and hold great promise in fabricating light modulators with ultra‐low‐field driving and macroscopic centimeter‐scale electrode spacing. However, their narrow bandgap and uncontrollable electroresponse severely restrict their modulated spectral region and performance, especially for the visible and ultraviolet regions. Here, we report a fluorographene liquid crystal, which has a wide bandgap of ∼5.5 eV and controllable electroresponse from modulation of fluorine doping ratio, and exceptional stability under deep‐ultraviolet exposure. As a consequence, a fluorographene liquid crystal‐based deep‐ultraviolet electro‐optic modulator is fabricated with negligible degradation after 5 h of ultraviolet irradiation under 0 and 12 V m ⁻¹ electric fields. The fluorographene liquid crystals expand the family of graphene liquid crystals and pave the way for broadening their applications in a variety of scenarios, as conceptually demonstrated with integrated sea‐land‐air solar‐blind communication for smart port applications.