Making chiral semiconductors practical

University at Buffalo researchers have created a new material system that allows “handed” (chiral) semiconductors to absorb visible light for the first time

By pairing a chiral perovskite with a non-chiral molecule, they successfully transferred the ability to distinguish light waves to a more practical energy range, paving the way for advanced sensors and faster optical communications.

The team solved a major hurdle in the development of chiral semiconductors—electronic materials that possess a “left-handed” or “right-handed” structure similar to DNA.

Published in Nature Communications, the study demonstrates a method to make these materials absorb visible light, a breakthrough that could revolutionise how we detect and transmit information.

The challenge of the “energy gap”

Chirality is a property where a structure cannot be superimposed on its mirror image, much like human hands. Chiral semiconductors are highly prized because they can distinguish between left- and right-circularly polarised light waves, but they have traditionally been limited because most do not absorb visible light efficiently.

This is because many chiral semiconductors have a large “bandgap”—the energy range where electrons cannot exist—meaning visible light does not carry enough energy to excite electrons across that gap. As a result, these materials primarily absorb only higher-energy UV light.

The assist solution

To address this, researchers combined a chiral perovskite semiconductor with an organic “dopant” molecule, F4TCNQ, which readily accepts electrons.

• The transfer:

  • When the material is exposed to visible light, chirality is transferred from the perovskite host to the dopant molecule via a specific charge-transfer state.

• The “assist”:

  • This process allows the system to respond to visible light while maintaining the “handedness” needed for next-gen electronics.

Future applications in optoelectronics

By adding visible light sensitivity to chiral structures, the researchers have opened the door to several next-generation technologies:

• Advanced sensors:

  • Polarised light sensors that can distinguish between different “shapes” of light.

• Optical communications:

  • Systems for more complex detection, processing, and transmission of information.

• Photocatalysis:

  • Using visible light to drive chemical reactions with specific handedness.