Laser-scribed graphene for sensors

    KNOXVILLE, TN, October 06, 2023 /24-7PressRelease/ -- Sensors are widely used to acquire biological and environmental information in medical diagnosis, health, and environmental monitoring. Graphene has been widely applied in sensor fabrication recently. Laser-scribed graphene (LSG) is simple, low-cost, environment-friendly, and has good conductivity and thermal stability. Primary LSG preparation methods are introduced, followed by LSG modification methods for sensor fabrication. Applications of LSG for stress sensors, biosensors, gas sensors, temperature sensors, and humidity sensors are summarized, focusing on multifunctional integrated sensors.

With the development of the information era, sensors capable of transmitting and detecting information have become the leading way to obtain information. Therefore, building a sensor system with a wide detection range, high sensitivity, and fast response is essential. Recently, graphene materials have received increasing attention for sensor applications due to their excellent electrical conductivity and physical, optical, thermal, and structural properties. These applications mainly include the detection of physical properties such as pressure and mechanical strain, chemical substances such as glucose, dopamine, proteins, heavy metals, and organic pollutants, as well as the detection of gas, temperature, and humidity.

In a new paper published in Light: Advanced Manufacturing, scientists led by Doctor Zhengfen Wang and Professor Xi Chen from the University of Shanghai for Science and Technology have reviewed laser-scribed graphene for sensor fabrication.

Graphene has been prepared with various methods, such as mechanical exfoliation, chemical vapor deposition (CVD), epitaxial growth, and chemical reduction of graphene oxide. High-quality graphene can be obtained by mechanical exfoliation, but the low efficiency prevents the large-scale production of graphene. The CVD method is considered the most promising method for preparing large areas and high-quality graphene, but the CVD method is constrained by high energy consumption and cost. Graphene films prepared by the epitaxial growth method have good electrical conductivity and high optical transmittance. However, they require high-temperature processing, energy consumption, and transfer cost. Chemical reduction of graphene oxide is low in cost and high in efficiency but creates environmental pollution problems during the preparation process. Therefore, graphene's low-cost, high-efficiency, pollution-free preparation methods remain very interesting.

The laser direct writing technique has recently attracted research applications in various fields due to its unique advantages of selective and localized reduction, precise and fast patterning, and the absence of masks and additional chemicals. With the laser direct writing technique, a laser is used to irradiate the carbon precursors and generate graphene by in-situ scribing. The whole laser scribing process takes only a few minutes, which significantly improves the efficiency of preparing graphene. This LSG by in situ, highly efficient, and flexible patterning. The excellent properties of high surface area, high thermal stability, and high electrical conductivity exhibited by LSG films have led to its use in a wide variety of applications. Those applications include photodetector, sensing, energy storage, memristors, holography, antibacterial applications, and antennas.

The research team discussed the preparation and modification of LSG, which can be prepared by different laser light sources and precursors, including carbon precursors such as GO and PI. Conventional graphene preparation methods are energy-intensive, costly, or environment-unfriendly, but this laser scribing method for graphene preparation overcomes these drawbacks. The LSG can be modified in one step by adjusting the laser parameters, atmosphere, and doping. The high surface area, good electrical conductivity, and simple and efficient fabrication process of LSG make it excellent potential for sensor applications.

The research team summarized the applications of LSG in stress sensors, biosensors, gas sensors, temperature sensors, and humidity sensors. The performance of the sensors can be optimized by using the appropriate laser power, scan speed, scan spacing, and suitable doping of the LSG in the preparation of the LSG. LSG sensors with integrated multiple sensing functions are further introduced. For multifunctional sensors, the crosstalk between different signals can be reduced by structural designs and patterning. In particular, the flexible patterned preparation and various flexible substrates make LSG also promising for wearable sensor applications.

References
DOI
10.37188/lam.2023.011

Original Source URL
https://doi.org/10.37188/lam.2023.011

Funding information
This work was supported by the Science and Technology Commission of Shanghai Municipality (Grant No. 21DZ1100500), the Shanghai Municipal Science and Technology Major Project, the Shanghai Frontiers Science Center Program (2021-2025 No. 20), the Queensland University of Technology (QUT) through the Centre for Robotics, the National Natural Science Foundation of China (Grant No. 62105206, 11974247), the China Postdoctoral Science Foundation (No.2021M692137) and the National Natural Science Foundation of China (Grant No. 11974247).

Contact
Zhengfen Wan
Institute of Photonic Chips, University of Shanghai for Science and Technology, Shanghai 200093, China, [email protected]

About Light: Advanced Manufacturing
Light: Advanced Manufacturing (LAM) is a new, highly selective, open-access, and free of charge international sister journal of the Nature Journal Light: Science & Applications. The journal aims to publish innovative research in all modern areas of preferred light-based manufacturing, including fundamental and applied research and industrial innovations.

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