 Hence, a correlation can be made between luminescence (intensity, quantum yield and in some cases lifetime) and the analyte concentration.Through careful design, and evaluation of the nature of the communication pathway, similar sensors based on the use of 'on-off' switching, or 'on-off-on,' or 'off-on-off' switching have been designed.The incorporation of chemosensors onto surfaces, such as quantum dots, nanoparticles, or into polymers is also a fast-growing area of research.