The visualization of the spatial distributions of gases from various sources is essential to understanding the composition, localization, and behavior of these gases. In this study, an inkjet-printed localized surface plasmon resonance (LSPR) subpixel gas sensor array was developed to visualize the spatial distributions of gases and to differentiate between acetic acid, geraniol, pentadecane, and cis-jasmone. The sensor array, which integrates gold nanoparticles (AuNPs), silver nanoparticles (AgNPs), and fluorescent pigments, was positioned 3 cm above the gas source. Hyperspectral imaging was used to capture the LSPR spectra across the sensor array, and these spectra were then used to construct gas information matrices. Principal component analysis (PCA) enabled effective classification of the gases and localization of their sources based on observed spectral differences. Heat maps that visualized the gas concentrations were generated using the mean squared error (MSE) between the sensor responses and reference spectra. The array identified and visualized the four gas sources successfully, thus demonstrating its potential for gas localization and detection applications. The study highlights a straightforward, cost-effective approach to gas sensing and visualization, and in future work, we intend to refine the sensor fabrication process and enhance the detection of complex gas mixtures.

Localized surface plasmon resonance (LSPR) offers rapid gas detection but faces selectivity and fabrication complexity challenges. This letter reports a method of fabricating LSPR gas sensor arrays with pixel patterns by inkjet printing. We developed Au/Ag nanoparticles ink with different compositions to collect spectrum information for accurate gas discrimination. In addition, principal component analysis (PCA) is used to realize the selectivity among four common gases that we often encounter in our daily lives. For the first time, this work demonstrates the fabrication of LSPR gas sensors through inkjet printing. Based on the LSPR phenomenon for gas detection, it shows great potential for rapid, sensitive, and selective gas detection for future research.

Localized Surface Plasmon Resonance (LSPR) technology facilitates rapid gas detection but faces challenges regarding selectivity and fabrication complexity. This study presents a pioneering method for fabricating LSPR gas sensor arrays with pixel patterns using inkjet printing. By adjusting the compositions of Au/Ag nanoparticle ink patterns and incorporating various fluorescent dyes, spectrum information can be gathered to enable precise gas discrimination. Specifically, we have integrated 32 units within a compact 5 × 10 mm ² area to form the subpixel sensor array, thereby minimizing sensor scale and enhancing gas selectivity. Additionally, principal component analysis (PCA) is employed to enhance selectivity among the six common gases. Notably, this study marks the first fabrication of LSPR gas sensor subpixel pattern arrays through inkjet printing, which combines Au/Ag nanoparticles and fluorescent pigments. Despite its limited scale, this device offers high information density. This work on subpixel patterned LSPR gas sensor arrays introduces a novel method for sensor fabrication and demonstrates significant potential for enabling rapid, sensitive, and selective gas detection in future research endeavors.

While localized surface plasmon resonance (LSPR) spectroscopy is highly sensitive to changes in refractive index, its applications have traditionally been confined to larger biological entities. The detection of smaller molecules remains an important yet challenging objective for this method. As a representative case of small molecule detection, gas detection through changes in bulk refractive index (RI) presents a significant challenge for LSPR spectroscopy. In this work, we report on the sensing of various gases using LSPR Au nano-urchin substrates. In preliminary experiments, although the substrates demonstrated rapid response and reversibility in gas detection, not all gases elicited a strong response. To further improve the response to gases, we encapsulated the nanoparticles with Metal Organic Frameworks (MOF) materials. Given their excellence in gas adsorption, MOFs significantly enhanced the response sensitivity of the sensors fabricated in our experiments. The sensitivity increased several-fold for various types of gases, including ammonia, which was previously undetectable, now eliciting an effective response. Furthermore, since LSPR sensors lack selectivity in detection, we spin-coated a layer of PEDOT: PSS film onto the substrates. As a commonly used material in ammonia detection, the chemical interaction between PEDOT: PSS and ammonia enabled the sensor to exhibit better detection results for ammonia compared to other gases.