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Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

 Федеральный исследовательский центр «Красноярский научный центр Сибирского отделения Российской академии наук»

Federal Research Center 
"Krasnoyarsk Science Center of the Siberian
Branch of the Russian Academy of Sciences"

Flexible optical sensor made of nanodisks can detect deformations in structures

24 June 2021 г.

Гибкий оптический сенсор из нанодисков сможет определять деформации в конструкциях
Krasnoyarsk scientists theoretically investigated the optical properties of a two-dimensional array of nanodisks and suggested a model of an optical strain sensor based on it. The idea of using the array arose when observing the microstructures of plants which are responsible for photosynthesis. The research results are published in the journal Nanomaterials.

Two-dimensional periodic arrays of nanoparticles have unique optical properties which can be used in designing and creating optical sensors and sensors. The sensitivity of such devices is determined by the geometry of the lattice and shape of its constituent elements, which imposes certain requirements on the technology of its production and, as a consequence, on the cost of the final product.

Scientists from the Federal Research Center "KSC SB RAS" and Siberian Federal University theoretically investigated a two-dimensional array of dielectric nanodisks and suggested a sensor model based on this array. The principle of operation of a real device will be based on the change in the resonance line wavelength of the structure during its deformation. Scientists found out that the optical response of the lattice when it is compressed and stretched in two mutually perpendicular directions is different: in one case, the resonance wavelength does not change, in the other, its shift is observed. The sensitivity of such a device is determined by the difference in resonance wavelengths related to the coefficient of deformation of the structure.

Such devices must have a high elasticity, determining their operating range. Therefore, scientists suggest placing nanoparticles in gel matrices or deposit them on a flexible substrate, for example, on a polydimethylsiloxane film. The elasticity of the material will prevent cracking when the structure is stretched or compressed. The use of such materials makes these structures look like soft matter or living tissue. It will allow the sensor device to behave like a “living plant” and to determine deformations in the structures based on the behavior of the array and the corresponding spectral shifts.

Similar arrays arise in the plant microstructures responsible for photosynthesis. Chloroplasts are located inside the plant's leaf cells, filled with a thylakoid membrane containing chlorophyll, which gives plants the green color. However, the pigment is unevenly distributed in the green part of the plants. The thylakoid is collected in disk-shaped folds, oriented towards the light source and arranged in arrays. It is possible that in this way the plant manages to concentrate the light flux in the area necessary for photosynthesis, or, on the contrary, to get rid of excessive radiation.

“Such structures can form the basis for optical sensors or detectors which will allow determining the presence of mechanical deformations and their magnitude. Such devices have high sensitivity, which is provided due to deformation of the lattice without additional changes in the shape of the nanoparticles themselves. This approach greatly simplifies the technological side of the device implementation and makes it much cheaper, ” says one of the authors of the study, Candidate of physical and mathematical sciences, researcher of the L.V. Kirensky Institute of physics KSC SB RAS, Rashid Bikbaev.

This work was supported by a grant from the President of the Russian Federation for young scientists-candidates of sciences (MK-46.2021.1.2).