LUMINESCENCE-BASED SENSORS - MICROHETEROGENEOUS AND TEMPERATURE EFFECTS

Many recent advances in remote optical sensors of O2, pH, and PCO2 are based on luminescence-type sensors. Both organic probes and transition-metal complexes are used on inorganic or organic polymer supports. Polymer systems are generally highly microheterogeneous and substantially affect the luminescence, quenching, and photochemistry. This complexity causes considerable difficulty in properly interpreting and correcting sensor behavior. Intimate understanding of the sensor-environment interactions and, especially, the role of microheterogeneity is critical for the rational design of new high-performance sensors/probes. We discuss different models for heterogeneity and demonstrate the surprising difficulty in establishing unique accurate models. The different models, their differences in sensor response, the magnitude of the uniqueness problem, and how to differentiate between models are discussed. In addition, for the new classes of inorganic sensors, temperature effects can adversely affect performance. The origins of these effects and the necessary parameters that must be controlled to best exploit them as sensors are explored.