Friday, October 2, 2009

Clipboards, Solar Cells & Fluorescence

Colored solar panels have been covered elsewhere, but reading some of the details gives me a new appreciation for my fluorescent clipboard.

In Professor Reisfeld's paper, she notes that for a transparent plate doped with a fluorescent species that "about 75-80% of the luminescence is trapped by total internal reflection in the plate having a refractive index of about 1.5. Repeated reflections of the fluorescent light carry the radiation to the edges where it emerges in concentrated form".

Now the plastic clipboard is not quite the same thing as fluorescent dye films deposited on both sides of an undoped substrate with photocells lining the edges but certainly the repeated internal reflections are cool nonetheless.

And while my clipboard doesn't have tape on it, the oil on my fingers has a different index of refraction which results in some frustrated internal reflection and glowing fingertips.