Advanced carbons in optoelectronics

Graphene anchors the optoelectronics sector through a rare combination of properties: a zero bandgap that can be tuned by bias or chemical doping, broadband light absorption and high carrier mobility. Graphene photodetectors cover a wavelength range from ultraviolet to terahertz that is inaccessible to conventional semiconductors, with response times below one picosecond, suiting high-speed optical communication. Single-walled carbon nanotubes serve as semiconducting channels in near-infrared phototransistors and, in film form, as transparent electrodes that reach under 100 ohms per square at over 85% transmittance.

Carbon nanotubes, graphene and MXenes all compete to replace indium tin oxide as flexible transparent electrodes in light-emitting diodes, displays and thin-film photovoltaics, processed at lower temperature on bendable substrates. Nanodiamonds with nitrogen-vacancy centres act as single-photon emitters at room temperature, emitting at about 637 nanometres, which makes them candidates for quantum communication. Graphene quantum dots, a form of emerging nano carbon, provide photoluminescence that can be tuned from ultraviolet to red by controlling dot size, for display colour conversion and bioimaging.

Carbon-based optoelectronics remains largely at the research to early-commercial stage. Graphene in flexible and wearable electronics, which includes optoelectronic uses, was valued at about $124 million in 2025 and is growing at roughly 27% a year to 2034, and electronics and telecoms account for about 53% of graphene market revenue. The broader material markets that supply the sector were valued at about $410 million for single-walled carbon nanotubes and about $67 million for MXenes in 2024.