Hi,
After finding out about bifacial solar panels here a little while ago, I've started looking to see if there's any such thing as stick-on PV for windows for partial shading in summer, etc. (I thought that those Sanyo and other bifacials looked rather pretty in 'transmission'.)
I'm guessing that some of the lighter semi-flexible polycrystalline panels might do it, but are unlikely to be attractive in rear view nor lightweight nor robust (ie just like me!)...
Also, they are unlikely to be optimised for whatever spectrum makes it through one or two panes of window glass I imagine.
My hamfisted Google searches haven't turned up anything specific so far.
This would mainly be experimental/novelty value for me right now, but there might be some useful mileage in such a product of course...
Applications as well as shading an overly-sunny room: charging phones, electronic mosquito repeller, adding a few Watts to an existing off-grid system, pumping a few Watts into the grid with a tiny grid-tie...
Rgds
Damon