A new tiny nitrogen gas sensor (Self-sustaining nanosensors) could help protect the environment from car pollution that causes lung disease and acid rain.
The sensor is in the form of nanowires, and one square millimeter (Self-sustaining nanosensors) of the fifth, which means that it will be easy to insert into a silicon chip.
And it doesn’t need any power source because it runs on its own solar power, said Shiyu Wei, first author of the paper reporting the research in Advanced Materials.
“As we connect devices like this to the Internet of Things, low power consumption is a big advantage in terms of system size and cost,” said Shiyu Wei, a doctoral student in the engineering department. Electronic Materials (EME) and TMOS Center of the Best.
“The device can also be adapted to detect other gases, such as acetone, which can be used as a breath test for diabetes.”
Current gas detectors are bulky and fast, and require a skilled operator. In contrast, the new device can quickly and easily measure less than 1 part per billion, and Miss Wei’s model uses a USB cable to connect to a computer.
Nitrogen dioxide is a type of NOx pollutant. In addition to contributing to acid rain, it is dangerous to humans even in small concentrations. It is a common car pollutant, and is also produced indoors by gas stoves.
The main element of the device is the connection PN – the engine of the cell – in the form of nanowire (small hexagonal pillars about 100 nanometers in diameter, 3 to 4 microns in height) resting on the base. Thousands of ordered nanowire solar cells, about 600 nanometers apart, form the sensor.
The entire device is made of indium phosphide, with its base and zinc forming the P segment, and the N segment at the tip of the nanowires, which is made of silicon. The central part of each nanowire is the one that is removed (the inner section, I) separating the P and N sections.
Light falling on the device causes a small current to flow between the N and P terminals. However, if the center of the PN junction is nitrogen dioxide, which is a strong oxidant that absorbs electrons, it will cause the current to drop.
The measurement of the trough is used to calculate the concentration of nitrogen dioxide in the atmosphere. A numerical example of Dr. Zhe Li, a postdoctoral fellow at EME, demonstrated that the design and fabrication of PN junctions is critical for increasing signaling.
The properties of nitrogen dioxide – strong adsorption, strong oxidation – allow indium phosphide to be easily distinguished from other gases. The sensor can be modified to detect other gases by activating the surface of the indium phosphide nanowire.
“The best goal is to detect more gas in one explosion,” said Professor Lan Fu, head of the research team. “In addition to environmental pollution, these sensors can be used for health, for example, for energy analysis for disease control people.”
To achieve these goals, the group is working together with the team of Professor Antonio Tricoli from the School of Chemistry Research at ANU Our Health in Our Hands Grand Challenge program.
Although nanowires have psychological advantages, their weakness is a challenge the team has overcome. They did this by surrounding a network of nanowires and polymer, which provided structural strength. The polymer layer did not extend to the nanowire, but left the N-doped tip exposed.
Next, a layer of gold is placed, sprinkled on the edge of the nanowires, covering one part of the wire and most of the polymer surface, except for a small area in the shade of gold rain n ‘back nanowire, which started. molecular gas detection site.
Small gas sensors are easy to integrate and can be calculated, Professor Fu said.
“Our nanowire material promises to realize a wide range of sensors with high performance and multi-functionality, which will enable them to be integrated into smart sensing networks,” he said.
These technologies will change our lives and our society in the coming years, and the implementation of Internet technologies is great for real data collection and autonomous response in applications such as air pollution monitoring, risk detection industrial chemistry, smart technology, community and personal health care.
