Real-time ultrafast moisture-sensing optical sensor TOU

Real-time ultrafast moisture-sensing optical sensor


Real-time ultrafast moisture-sensing optical sensor

Project Map and the principle behind the Ultrafast Full-Color Colormetric Humidity Sensor. Credit: POSTECH

The Hercules beetle, native to South America, has an attractive ability to change its shell color depending on the conditions of the outside humidity. This is because the inside of the beetle’s shell has a pore-like structure with square holes. When light of specific wavelengths hits the shell, it reflects them and shows different colors; And these wavelengths vary with humidity. Recently, this beetle-like humidity-sensing sensor, which is 10,000 times faster than conventional optical sensors, was proposed.

A POSTECH research team led by Professor Junzuk Ro (Department of Chemical Engineering and Mechanical Engineering) and Ph.D. Candidates Chunghwan Jung and Jaehyuck Jang (Department of Chemical Engineering), Sung-Hoon Hong and Dr. Soo-Jung Kim (in collaboration with Electronics and Telecommunications Research Institute, ETRI) and Professor Young Min Chang (Gwangju Institute of Science and Technology, GIST), has developed an ultrafast moisture-responsive color measurement sensor. The results of the study were published Scientific advances.

In our daily lives, light sensors are already being used to measure the electrocardiogram and air quality. These sensors detect changes in their surroundings and use light to convert them into digital signals.

The research team developed a colorful sensor with a metal-hydrogel-metal structure using an irregular metal nanoparticle layer – a cytosine hydrogel – and a reflective substrate. As the external humidity changes, the vibrational frequency of the sensor changes due to the characteristic of cytosine hydrogel, which swells in the wet state and shrinks again in the dry state.

This new sensor has an ultrafast speed 10,000 times faster than conventional Fabry-Ford interferometer-based optical sensors. This rapid reaction is fast, thanks to the porous space between the nanoparticles that creates a beetle-like sensor that changes color depending on the humidity.

“This new moisture sensor is unique in that it allows measuring production at low cost even when nanomaterials and nano structures are used,” explained Professor Rowe, who led the study. “Introducing moisture-responsive color pixels in security codes enables application towards security tags for moisture-sensitive electronics, banknotes, passports and identity cards.”

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                                        Self-illuminating smart windows on rainy days
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                                                                                            <strong>More info:</strong>
                                            Chunghwan Jung et al, Etalan, based on irregular-nanoparticles for ultrafast moisture-responsive color sensors and anti-counterfeit displays <i>Scientific advances</i> (2022)  <a data-doi="1" href="" target="_blank" rel="noopener">DOI: 10.1126 / sciadv.abm8598</a>



                                            Presented by Bohang University of Science and Technology

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                                             <strong>Quote</strong>: Real-time Ultrafast Moisture Sensor Optical Sensor (2022, April 13) Retrieved April 13, 2022 from

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