The construction of graphene‑based microfibers with reinforced mechanical and electrical properties has been the subject of numerous researches in recent years. However, the fabrication of graphene‑ based fibers with remarkable optical features still remains a challenge and has not been addressed so far. This paper aims to report a series of flexible self‑assembled fibers, synthesized through a few‑minute sonication of thermally oxidized graphene oxide nanosheets, so‑called Nanoporous Over‑Oxidized Graphene (NOG), in an acidic medium. These free‑standing glassy fibers were classified into four distinct morphological structures and displayed a collection of intriguing optical properties comprising high transparency, strong birefringence, fixed body colorations (e.g. colorless, blue, green, and red), tunable interference marginal colorations, UV–visible‑near IR fluorescence, and upconversion emissions. Moreover, they exhibited high chemical stability in strongly acidic, basic, and oxidizing media. The foregoing notable attributes introduce the NOG fiber as a promising candidate both for the construction of graphene‑based photoluminescent textiles and the development of a wide variety of optical applications.
