Quantum dot solution fluorescing. The cuvette containing the solution is placed on the stage of an epifluorescence microscope and illuminated with blue light (wavelength of 488 nanometres). The sample is excited throughout its thickness. Quantum dots are nanocrystals of semiconductor material that emit photons when excited. The size of the quantum dot can be tuned during manufacturing to produce a certain wavelength of photon emission. Quantum dots have a number of applications including use in light emitting diodes (LEDs), quantum computing, solar panels and labelling biological tissue.