The beauty of nanotechnology lies in the appearance of special and sometimes surprising properties of matter below a certain size threshold on the nanometer scale. See how I made a small contribution in getting blue light out of simple silicon nanoparticles.
I had the pleasure to work together with a very talented team from the Charles University in Prague, led by Professor Jan Valenta of the Faculty of Mathematics and Physics, and Anna Fucikova serving as a PhD student at that time. They found a very nice and practical way of creating <2nm silicon nanoparticles via etching of silicon wafers. Those particles exhibited astonishing optical properties, namely emitting in the blue region of visible light, so “simple” silicon particles suddenly became a candidate for building LEDs (light emitting diodes) in the ultraviolet-blue region of light, which typically is not readily accessible. A few years earlier, a team of Japanese scientists have discovered blue light emitting materials based on gallium nitride, at that time an incredible finding as blue LEDs where supposed to be almost impossible to create. They did it, yet gallium nitride and its doping materials are more complex (and maybe also toxic) than simple silicon nanoparticles my collaborators found to show very similar optical properties. The Nobel Prize was awarded to this Japanese team in 2014, please find an enlightening article published by the Swedish Royal Academy of Sciences below.
This really shows the sometimes astounding properties appearing when regular materials known from everyday life (like silicon wafers in this case) are forced to reveal their true nature when we cut them down to the nanometer scale - and quantum effects take over. This is why I live for nanotechnology and will stay connected to the field as much as I can.
There are numerous other examples for surprising properties when going down to nanoscale dimensions, one of them is graphene — essentially being just pure carbon, but having amazing properties (like mechanical stability and electrical properties) when looking at single-atomic layers only.
Honestly, my contribution in this case was very little, we dried colloidal suspensions of those silicon nanoparticles and imaged them with AFM, confirming the size being less than 2 nanometers, and also confirming their uniformity which is apparently needed for getting consistent optical effects at a good quantum yield.
So, let’s see how the journey continues with those tiny silicon particles being used one day maybe to serve us all with nice blue light!
This is the link for our article in “New Journal of Physics”, enjoy reading!
And here is the link to the Royal Swedish Academy of Sciences, delivering the Nobel Prize in Physics in 2014 to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura. The title of this publication is “Blue LEDs — Filling the world with new light”.