Charged trions in carbon nanotubes keep their original chirality

A Tokyo Metropolitan University team separated left- and right-handed single-wall carbon nanotubes and created charged trions electrochemically from two electrons and one hole, or two holes and one electron. High-precision circular-dichroism measurements showed that the trions retained the same chirality as their parent excitons and nanotubes at roughly the same strength. Because trions can be created by injecting electrons or holes, the result makes electrical control of amplification, detection and modulation of circularly polarized light more plausible. It remains a basic materials experiment, with device lifetime, scalable manufacturing and system integration still unproven.