Breakthrough in SnO2 Nanofilm Multi-Sensor and Wireless Gas Detection System

In late 2024, researchers from Hanoi University of Science and Technology (HUST) successfully completed a breakthrough project titled “Development of SnO₂ Nanofilm Multi-Sensors and Testing of a Wireless NH₃ and H₂S Gas Detection System”. Funded by the National Foundation for Science and Technology Development (NAFOSTED), the project achieved notable progress in sensor materials and architecture for remote environmental monitoring.

Led by Assoc. Prof. Nguyen Van Duy from the School of Materials Science and Engineering, the team engineered multi-core structures with enhanced selectivity, marking a significant step forward in remote environmental monitoring technology.

Pioneering real-world application of a unique sensor model

For over a decade, Assoc. Prof. Nguyen Van Duy and his team at HUST have pursued nano-material research for sensor applications. Building on earlier results, they selected suitable materials and technologies to develop a new project aimed at real-world use.

The team worked on developing compatible fabrication processes, circuit designs, analytical software, and electronic systems to create and test prototype devices. They set up three main goals for the research:

1. Develop a SnO₂-based multi-sensor system to detect NH₃ and H₂S gases.
2. Build a device to process sensor signals and display gas concentrations.
3. Set up a remote air monitoring station with wireless data transmission to phones and ipads.

  Explaining this recent research in simple terms, Assoc. Prof. Nguyen Van Duy shared that unlike typical commercial devices that rely on single sensors, their study developed a new multilayer nanofilm structure, with each layer designed to react differently with specific gases. By combining these layers, the team created a multi-sensor system where each sensor provides unique data for improved analysis.

Instead of building separate devices, the scientists integrated five distinct sensors onto a single chip. This compact design can be scaled from a few to hundreds of sensors, depending on the balance between performance and technological complexity, marking a significant step forward in smart, selective gas detection.

Overcoming challenges through international collaboration in research

Despite their expertise in microelectronics, researchers at HUST faced a major challenge: creating electronic components that are not only stable and precise but also consistent in large quantities. In the past, dozens or even hundreds of sensors had to be made just to find a few that met quality standards. For this project, however, five sensors needed to function uniformly on a single chip, each with five identical, stable electrodes. While this is manageable in optimized factory conditions, doing it by hand in a university lab is much harder.

To overcome this, the team collaborated with a Vietnamese-Swedish professor and spent years perfecting the process. They also worked with scientists from Italy, China, and South Korea to successfully carry out the research.
 

Despite facing challenges in securing high-quality human resources, especially PhD candidates, the HUST team successfully achieved its goals in developing materials and multi-sensor devices. The project resulted in four ISI-indexed journal articles, one national patent, two additional publications, and the training of several master's and PhD students,contributing valuable expertise in nanofilm electronics and advanced materials to both the university and the country.

Applying research wherever gas is present

The successful integration of compact, low-power multi-sensor chips into prototype devices marks an important milestone for the project. These chips lay the groundwork for future development of complex, multifunctional analysis systems. The multi-sensor platform can analyze gases not only in the environment but also in food, detect wildfire risks, monitor water pollution, and even survey volcanic activity.

“Wherever gas is present, this multi-sensor research can be applied,” said Assoc. Prof. Duy.

Looking ahead, HUST aims to develop smaller, low-power sensors that are easy to mass-produce and package, enabling technology transfer or commercialization when market demand arises.