A crystal with dual charge transfer capability
To understand what makes this pyrazinacene crystal special, it is important to know a bit about the charge transfer (electron movement) process that actually makes the crystal color change.
This can happen within a single molecule (intramolecular charge transfer, or ICT) or between two different molecules (intermolecular charge transfer, or CT). While ICT is often used in dyes and OLEDs, CT plays a major role in solar cells and semiconductors.
However, combining both types of charge transfer in one material has been challenging. This is “because it requires precise control over the molecular design and intermolecular interactions. Additionally, the hybrid system must be composed of material that remains stable under such rapid (electron) transfer conditions,” The SIT team explained.