Single-Molecule Photoswitching: New Control Technique

Researchers from the Department of Physical Chemistry at the Fritz Haber Institute have achieved a significant breakthrough in nanoscale optoelectronics. Their study, featured in Nature Communications, reveals a pioneering method for atomic-level control over plasmon-induced single-molecule switching, potentially transforming future nano-device technology.

Nanoscale optoelectronics is an emerging field focused on developing electronic and photonic devices at an incredibly small scale. Mastering photoreaction control at the atomic scale is crucial for refining these devices. Previously, localized surface plasmons (LSPs)—light waves on nanoscale materials—were mainly used in metallic structures, limiting their application in optoelectronics.

Atomic-Level Photoswitching Control

This research showcases a new use for LSPs on semiconductor materials. By utilizing a plasmon-resonant tip with a low-temperature scanning tunneling microscope, scientists have achieved precise manipulation of single organic molecules on silicon surfaces. The LSPs facilitate the reversible switching of these molecules by altering their chemical bonds with silicon. The precision of this switching can be adjusted to within 0.01 nanometers.

An important aspect of this discovery is the ability to tailor the optoelectronic properties through atomic-level chemical modifications. For instance, replacing an oxygen atom with a nitrogen atom in a different molecule can prevent switching. This kind of fine-tuning is essential for crafting single-molecule optoelectronic devices with specific functions.

Implications for the Future

This study addresses a major obstacle in the field by providing a method for precise control over single-molecule reactions. The findings suggest that metal–single-molecule–semiconductor nanojunctions could become key platforms for next-generation nano-optoelectronics. This advancement could lead to substantial progress in sensors, light-emitting diodes (LEDs), and photovoltaic cells, enhancing the capabilities and versatility of these technologies.