Emitting Light With Nanotubes

Nanomaterials that emit light will someday be key components of photonic and optical devices. But first, chemists must develop transistors that can produce photons efficiently at low voltages without much hysteresis (lag in response of current to voltage changes). By linking arrays of aligned carbon nanotubes with liquid electrolytes, Jana Zaumseil of Argonne National Laboratory, John A. Rogers of the University of Illinois, Urbana-Champaign, and colleagues have constructed field-effect transistors that come closer to fitting the bill (ACS Nano, DOI: 10.1021/nn9005736). They find that current-switching gates made of ionic liquids or lithium perchlorate in polyethylene glycol work far better than conventional solid oxide gate materials. The new devices operate at remarkably low voltages (–0.4 to –3 V) without much hysteresis, but they are not yet particularly efficient in converting current to light.