#South Korea #Incheon #Incheon National University #eco-friendly technology #Organic Gas Sensors

Introduction

In recent years, the increase in electronic waste has posed significant environmental challenges, particularly in the realm of sensor technologies. Recognizing this issue, researchers at Incheon National University have developed a novel approach to creating eco-friendly gas sensors using organic field-effect transistors (OFETs). These sensors demonstrate a promising blend of high performance and sustainability by employing biodegradable polymers.

The Challenge with Traditional Sensors

Traditionally, gas sensors utilizing organic semiconductors face limitations primarily due to their vulnerability to moisture and oxygen, which leads to performance degradation over time. This inherent instability not only diminishes the sensors' effectiveness but also contributes to electronic waste as they reach the end of their operational lives. The need for portable sensors that can accurately detect harmful air pollutants, like nitrogen dioxide (NO₂), has never been more pressing, particularly due to increasing rates of respiratory diseases linked to air quality.

Eco-Friendly Innovation

The research team, led by Professor Yeong-Don Park from the Department of Energy and Chemical Engineering, embarked on a mission to mitigate the limitations of traditional gas sensors. By leveraging advanced solvent engineering, they have succeeded in creating high-performance OFET gas sensors that utilize blended polymer films made from poly(3-hexylthiophene) (P3HT) and poly(butylene succinate) (PBS). PBS is celebrated for its biodegradable properties, offering a solid foundation for developing sustainable technology.

Fabrication Process

To fabricate the sensors, a novel solvent approach was implemented. The researchers prepared blended solutions of P3HT and PBS using two solvent mixtures: chloroform (CF) and a blend of chloroform with dichlorobenzene (CFDCB). Depositing these solutions onto silicon substrates formed the foundation of the sensors. Notably, the choice of solvent influenced the final structure of the active polymer layer, a critical aspect that determined the sensors' performance.

The CF-processed films demonstrated horizontal phase separation, resulting in an uneven surface structure, while the CFDCB-processed films exhibited vertical phase separation, leading to a more uniform surface. This structural distinction was key in offering a comparative analysis of sensor performance.

Performance Metrics

Testing revealed that the sensor performance was strongly dependent on the content of PBS in the polymer blend. While both sensors exhibited decreased electrical performance with an increase in PBS content, the CFDCB-processed sensors maintained stability even with up to 90% PBS. Comparatively, the CF-processed sensors became non-functional when PBS exceeded 50%.

Moreover, the gas-sensing capabilities of both sensor types were evaluated. Results indicated a pronounced increase in sensitivity to NO₂, SO₂, and CO₂ with higher PBS content. Remarkably, the CF-processed films exhibited heightened sensitivity, while the CFDCB films retained stable sensitivity, demonstrating their reliability for long-term monitoring applications.

Implications for the Future

The development of these eco-friendly sensors represents a significant step toward sustainable gas sensing technologies. Not only do they hold the potential to reduce electronic waste, particularly in natural environments, but they also open new avenues for large-scale sensor applications. As the world becomes increasingly aware of the importance of eco-friendliness in technology, innovations like these from Incheon National University could set the stage for responsible technological advancements.

Professor Park concludes, "Our eco-friendly and resource-efficient sensors open up new possibilities for environmentally sustainable gas sensing technologies suitable for large-scale or disposable applications. In the long term, biodegradable organic sensors could significantly reduce electronic waste, especially for sensors deployed in natural or marine environments." With studies published in the 'Chemical Engineering Journal,' this breakthrough may well be just the beginning of eco-friendly advancements in gas sensing technology.

Reference

• - Title of Original Paper: Solvent-driven phase separation strategy for eco-friendly high-performance organic gas sensors
• - Journal: Chemical Engineering Journal
• - DOI: 10.1016/j.cej.2025.168910