Nanoengineering light-emitting materials for sensing applications

Gas sensors have important applications in a wide variety of fields, including air pollution monitoring, exhaled breath tests for disease diagnosis, illicit drug recognition, and detection of explosives. Electrochemical and optical sensors are the most widely investigated gas sensors. Although electrochemical sensors have been applied widely in commercial applications, optical sensors are currently receiving significant interest due to several advantages, such as a reversible mechanism, precision and accuracy, remote sensing via optical fibers, and ease of miniaturization. Recent studies have shown that surface plasmon resonance (SPR) effect can be highly advantageous due to their unique ability to monitor molecular binding events in real time with significant sensitive enhancements. Furthermore, the SPR effect can be modulated using nanoengineered materials in combination with luminescence materials rather than continuous thin film layers to achieve higher limits of detection. Luminescence materials that exhibit fluorescence and phosphorescence combined with SPR have been used as transducing mechanisms for creating next-generation optical sensors. This chapter will provide a comprehensive review of gas sensors based on the localized surface plasmon resonance (LSPR) phenomenon, including LSPR theory, the variety of nano-engineered light emitting materials, and different strategies that have been employed for improving the sensitivity and selectivity of optical sensors.