Photoluminescence chemical detection using

An attractive alternative to organic fluorophores in formulated polymeric sensor films for chemical detection is to use inorganic luminescent materials. Semiconductor nanocrystals have a dramatically improved photostability and are attractive as luminescent labels.1415 However, some nanocrystals also exhibit photoluminescence (PL) that is sensitive to the local environment. For example, it was observed that PL of CdSe nanocrystals incorporated into polymer thin films responded reversibly to different gases.16 Because in sensing applications nanomaterials bring previously unavailable capabilities1719 and unexpected results,20 23 we explored the environmental sensitivity of semiconductor nanocrystals upon their incorporation in different rationally selected polymeric matrices.24 26... 

Although there are numerous techniques which can be used to detect chemical perturbations, they often lack sensitivity. Photoluminescence spectroscopy can be considered ideal because of its high sensitivity and nondestructive nature (14, 33, 34). 

In this section we deal with quantitative steady-state luminescence intensity determination in solution, at a fixed emission wavelength, using a commercial spectrofluorimeter with right-angle excitation (perpendicular geometry). These kind of measurements are particularly important in analyte detection, titrations, quenching and sensitization experiments, photoreaction and photoluminescence quantum yield determination, and whenever a luminescence signal is used to monitor a chemical process. 

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