Excimer-forming sensor molecules

Changes to the fluorescence properties of a probe due to stacking effects can also be exploited in piezochromic macroscopic sensors. One such example is based on the liquid crystalline molecule cyano-substituted oligo(p-phenylene vinylene) (OPV), which forms columnar crystal stacks with pronounced n-n interactions, leading to excimer fluorescence [42]. In the solid state, the monomer emission is observed as a structured band in the green (2em = 481 nm). On exposure to external pressure, such as grinding with a pestle and mortar, the emission band is red-shifted (Aem = 548 nm) and the vibrational stracture is lost. The emission properties can be reversed upon heating the sample at 130 °C. The choice of... 

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