Effect of excitation wavelength and light exposure time on quantum dots luminescent properties

Optical biosensors constitute a major part of biosensors currently under development. Indeed, they generally show high specificity and sensitivity with a reduced size while remaining economical. Within this context, we combine the detection of the Förster resonance energy transfer (FRET) phenomenon, which is known for improving the sensitivity of sensors, and CdTe quantum dots (QDs), which are water-soluble and have specific optical properties to develop a sensing device. Although there are numerous examples of biosensors based on QDs and FRET, they are usually used without particular care concerning the wavelength and the power of the light source. In this work, we study the influence of these parameters on the QDs optical properties in order to determine the most adapted for future biosensor applications based on FRET phenomenon. Similar experiments are also conducted on a commonly used organic dye, the fluorescein, to highlight specific QDs behaviour.