Carbon Structures with Three-Dimensional Periodicity at Optical Wavelengths

TLDR

The authors fabricated three‑dimensional periodic porous carbons by infiltrating silica opal templates with carbon precursors, sintering to form inter‑sphere interfaces, and then removing the silica, mimicking natural opal formation. The resulting carbons included diamond‑ and glassy‑carbon inverse opals from volume filling and graphite‑sheet inverse opals from surface templating, all of which strongly diffract light and represent dielectric or metallic photonic crystals that could serve as photonic band‑gap materials.

Abstract

Porous carbons that are three-dimensionally periodic on the scale of optical wavelengths were made by a synthesis route resembling the geological formation of natural opal. Porous silica opal crystals were sintered to form an intersphere interface through which the silica was removed after infiltration with carbon or a carbon precursor. The resulting porous carbons had different structures depending on synthesis conditions. Both diamond and glassy carbon inverse opals resulted from volume filling. Graphite inverse opals, comprising 40-angstrom-thick layers of graphite sheets tiled on spherical surfaces, were produced by surface templating. The carbon inverse opals provide examples of both dielectric and metallic optical photonic crystals. They strongly diffract light and may provide a route toward photonic band-gap materials.