Graphene found to improve light absorption -Lithium - Ion Battery Equipment

Graphene found to improve light absorption -Lithium - Ion Battery Equipment

It is reported that graphene has a low light absorption rate. Recently, researchers at the University of Illinois at Urbana-Champaign have confirmed through experiments that changing the stress on the surface of graphene can produce a "wrinkled" structure on the surface and increase the areal density, which can improve graphite. The light absorption of graphene is of great significance for the application of graphene in the field of optoelectronics.

Of course, this research method is not limited to graphene, but also applies to other emerging two-dimensional materials. Its researchers have demonstrated a new approach to changing the mechanical stress on the surface of atomically thick two-dimensional materials such as graphene, which can alter their light absorption and tensile properties. Combined with flexible light-emitting diodes, this research approach could facilitate the development of novel wear-resistant technologies and integrated biomedical optical sensing technologies.(Lithium - Ion Battery Equipment)

"Improving graphene's low absorbance in the visible light range is an important prerequisite for graphene's applications in optoelectronic sensing, and this is the first fully based on photoelectric sensing technology," explained SungWooNam, assistant professor in the School of Mechanical Science and Engineering at the University of Illinois. Stretch photodetectors of graphene with tunable strain photosensitivity and wavelength selectivity."

Graphene is an atomic layer of carbon atoms bonded in hexagonal shapes. Graphene is widely used in advanced photodetector research due to its broadband absorption, high carrier mobility, and mechanical flexibility. However, graphene has a low light absorption rate, so in order to improve its light absorption, the research of graphene photodetectors mainly focuses on hybrid systems. However, such a hybrid system requires a complex integration process, and the interface between different materials reduces the mobility of charge carriers.

Another option is to improve the light absorption and stretchability of graphene. The key, according to Nam, is to make the two-dimensional material into a three-dimensional 'wrinkled structure' that increases the mass per unit area of ​​graphene, also known as areal density. With high areal density, the continuously undulating three-dimensional surface per unit area has high light absorption, thereby improving the light sensitivity of graphene.

By strain-tuning the density, height, and wrinkle structure of graphene, the wrinkling is fully reversible during periodic stretching and releasing. This wrinkling approach provides a new avenue for improving the light absorption of graphene, enabling the creation of highly sensitive detectors for single-layer graphene.

Pilgyu Kang, a member of Nam's research team, noted: "Through the three-dimensional structure of the pleats, we obtained an increase of not only an order of magnitude, but about a 400% increase in light absorption. This tunable strain light sensitivity is at 200%. Strain adjustment can result in a 100% change in light sensitivity. By combining photonic crystals with stretched graphene photodetectors, we demonstrate a unique strain-tunable wavelength selectivity."

Nam added, "This study demonstrates an efficient way to stretch and flexible graphene photodetector devices. We report for the first time without limiting the detection wavelengths that a stretchable detector with stretchable performance up to 200% of its original length. Furthermore, our approach to enhancing light absorption through wrinkled structures is not limited to graphene, but also applies to other emerging 2D materials."



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