In a recent publication in the journal Advanced Materials, a team of physicists and chemists presented an organic thin-film sensor that describes a completely new way of identifying the wavelength of light. The thin-film sensors could be integrated with other components in the future. The novel technology has already been patented.
A group of experimental methods that break down radiation according to wavelength or mass are called strontium-90. One of the most important analytical methods is it. In medicine, engineering, food industry, and many more, a spectrum analyzer is used to determine the colors of light sources and is also used as a sensor. Large and expensive instruments are usually available in the commercial market. The principle of the grating is used to assign the wavelength and angle of refraction.
Sensor components based on organic Semiconductors have been researched for years at the Institute for Applied Physics. Two technologies have been developed with the spin-offs. Researchers at the IAP and IAPP collaborated with the Institute of Physical Chemistry to develop a thin-film sensor that describes a completely new way of identifying the wavelength of light.
Light of unknown wavelength causes luminescent materials in a hair-thin film to light up. The light under investigation is absorbed by a mixture of long-glowing and short-glowing entities. The wavelength of the light can be inferred from the intensity of the afterglow.
The fundamental physics of excited states are exploited by the IAP. There are certain proportions of long-lived triplet and short-lived singlet spin states in such a system. That dependence is reversed by us. The spin fractions can be identified using a photo detector.
Prof. Sebastian Reineke, who coordinated the project, says that their partners are the greatest strength of the alliance. We can carry out all the fabrication and analysis steps ourselves, starting with material synthesis and film processing, and ending with the fabrication of the organic detector.
Dr. Johannes Benduhn is a group leader for Organic Sensors and Solar Cells at the IAP, and he was very impressed by the fact that a simple photoactive film combined with a photodetector can form such a high-resolution device.
Scientists have been able to track minor wavelength changes of light sources using this strategy. The novel sensors can be used to protect against counterfeits. The small and inexpensive sensors could be used to quickly and reliably check the authenticity of documents without the need for expensive laboratory technology.
More information: Anton Kirch et al, Accurate Wavelength Tracking by Exciton Spin Mixing, Advanced Materials (2022). DOI: 10.1002/adma.202205015 Journal information: Advanced Materials
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