Team develops method to control single-molecule photoswitching

Scientists from the Department of Physical Chemistry at the Fritz Haber Institute have made a groundbreaking discovery in the field of nanoscale optoelectronics. The study, published in the journal Nature Communications and titled “Atomic-precision control of plasmon-induced single-molecule switching in a metal-semiconductor nanojunction,” presents a method for achieving unprecedented control over photomolecular switching. This advance could transform the future of nanodevice technology.

Nanoscale optoelectronics is a rapidly evolving field that focuses on the development of electronic and photonic devices at the nanoscale. These tiny devices have the potential to revolutionize technology, making components faster, smaller, and more energy efficient.

Precise control of photoreactions at the atomic scale is essential to miniaturize and optimize these devices. Localized surface plasmons (LSPs), which are light waves generated on material surfaces at the nanoscale, have become powerful tools in this field, capable of confining and amplifying electromagnetic fields. So far, the application of LSPs has been mainly limited to metallic structures, which the team believes could limit the miniaturization of optoelectronics.

Beyond the nanoscale: controlling photoelectric switching with atomic precision

New research focuses on using LSPs to achieve atomic-level control of chemical reactions. One team has successfully extended the functionality of LSPs to semiconductor platforms. Using a plasmon-resonant tip in a low-temperature scanning tunneling microscope, they enabled the reversible lifting and lowering of individual organic molecules on a silicon surface.

The LSP at the tip induces the breaking and formation of specific chemical bonds between the molecule and silicon, resulting in reversible switching. The switching rate can be adjusted by the tip position with exceptional precision down to 0.01 nanometers. This precise manipulation enables reversible changes between two different molecular configurations.

Another key aspect of this breakthrough is the ability to tune the optoelectronic function through molecular modification at the atomic level. The team confirmed that photoswitching is inhibited for another organic molecule, in which a single oxygen atom not bonded to silicon replaces a nitrogen atom. This chemical tailoring is essential for tuning the properties of single-molecule optoelectronic devices, enabling the design of components with specific functionalities and paving the way for more efficient and adaptable nano-optoelectronic systems.

Future directions

This research addresses a major obstacle in the development of nanoscale devices by proposing a method to precisely control the dynamics of single-molecule reactions. Furthermore, the results suggest that metal-single-molecule-semiconductor nanojunctions could serve as versatile platforms for next-generation nano-optoelectronics.

This could enable significant advances in sensors, light-emitting diodes and photovoltaic cells. The precise manipulation of individual molecules under the influence of light could have a significant impact on the development of these technologies, providing increased capabilities and flexibility in device design.