Researchers at Linköping University, Sweden, have developed a sensor that can detect circularly polarized light in the red, paving the way for applications such as more reliable autonomous vehicles and other areas where night vision is important. The material used in organic solar cells also proves useful as light sensors in electronics.
An innovative sensor for circularly polarized light
Circularly polarized light is a special type of light, reflected by certain insects such as glowing-winged beetles, firefly larvae and colorful mantis shrimp. This light is due to microscopic structures in their shell that reflect electromagnetic waves of light in a specific way. Circularly polarized light also has many technical applications, such as satellite communication, bioimaging, and other sensing technologies.
The researchers of theLinkoping University have developed a material, normally used for organic solar cells, capable of capturing these particular light beams.
According to Feng Gao, professor at the Department of Physics, Chemistry and Biology (IFM) at Linköping University, “Building high-quality sensors capable of detecting circularly polarized light in the near-infrared spectrum has long been a challenge. But thanks to the development of a material normally used in solar cells, we can now detect circularly polarized light across the entire visible light spectrum.»
Promising applications for night vision
This discovery opens the way to technical solutions where night vision is essential, such as in self-driving cars. The fact that the material is lightweight and the manufacturing process is simple makes it suitable for use in small and inexpensive sensors.
The material used in this study is a non-fullerene polymer, which has proven beneficial in solar cells as well as other uses, such as light sensors. This material’s ability to detect circularly polarized light is due to its chirality, which is the way molecules interact with light.
Next steps in research
Li Wan, postdoctoral researcher at the IFM, explains that “The next step is to extend these tests to several different materials and examine how molecules and light interact with them. In this way, we hope to be able to increase efficiency.»
Rui Zhang, also a post-doctoral fellow at the IFM, adds: “Controlling packaging between molecules could be very important“.
Synthetic
Researchers have developed a sensor capable of detecting circularly polarized red light, using a material normally used in organic solar cells. This advancement could enable applications such as more reliable autonomous vehicles and other areas where night vision is crucial. The next steps in the research will be to study other materials and improve the efficiency of these sensors.
For a better understanding
1. What is circularly polarized light?
Circularly polarized light is a special type of light reflected by certain insects and has varied technical applications, such as satellite communication, bioimaging and other sensing technologies. It is characterized by a spiral electromagnetic field, rotating either to the right or to the left.
2. What material is used to detect this light?
Researchers at Linköping University have developed a material, normally used for organic solar cells, capable of capturing these particular light beams. It is a non-fullerene polymer, which has advantages in solar cells and other uses, such as light sensors.
This material’s ability to detect circularly polarized light is due to its chirality, which is the way molecules interact with light. Using chirality, different molecules can detect whether electromagnetic radiation is turning right or left.
4. What are the potential applications of this sensor?
This discovery opens the way to technical solutions where night vision is essential, such as in self-driving cars. The fact that the material is lightweight and the manufacturing process is simple makes it suitable for use in small and inexpensive sensors.
5. What are the next steps in the research?
The next steps in the research will be to study other materials and improve the efficiency of these sensors, by examining how molecules and light interact with them.
Main illustration legend: Rui Zhang, post-doctoral researcher at IFM, is one of the main authors of the article published in Nature Photonics. Credit: Olov Planthaber
Article: Sensitive near-infrared circularly polarized light detection via non-fullerene acceptor blends; Li Wan, Rui Zhang, Eunkyung Cho, Hongxiang Li, Veaceslav Coropceanu, Jean-Luc Brédas & Feng Gao; Nature Photonics 17 (2023), published online June 8. DOI: 10.1038/s41566-023-01230-z
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