Emitting white light ....

A phosphorescent molecular resembling a “butterfly” flipping its wings can generate dual (white) emission upon photo excitation. Credit: M. Han et al./Angewandte Chemie

White light does not exist. It is just a figment of our imagination. Our brain "invent" the white light by receiving signals from photoreceptors (cones) in our eyes retina of blue, green and red light detected. Provided these signals are in the right mix the brain interprets them as "white light".

Using semiconductors (LED) engineers can create components that emits light at different wavelengths, that is different colours. By mixing different kind of semiconductors more wavelengths can be generated so that the perceived effect is white light. 

Now, researchers at Florida State University have managed to use a single molecule to produce several wavelengths resulting in the emission of "white light".

The molecule looks like a butterfly, and, as a butterfly, can flap its wings.This flapping can result in the emission of both blue and red light leading to the perception of “white”. The actual wavelength of the emitted light depends on the temperature, actually it is very sensitive to temperature, making this molecule the smallest, and a very precise thermometer. It is so small, that researchers have proposed to use it to measure the temperature inside a cell!

The molecule was created by Biwu Ma, associate professor in the department of chemical and bio-medical engineering in the FAMU-FSU College of Engineering several years ago but it is only now that the team of researchers have been able to put its peculiar properties to practical use.

It is nice to see how, eventually, basic research moves into the application space, but that takes several years! Notice that the shift has been from basic science into thinking of its possibility of practical application. We are not yet into a concrete application. For this further step more engineering is required, with a keen look at market opportunity.

Author - Roberto Saracco

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