Spraying a UV protectant on the solar cell of solar garden light (convert, lights)

[MediocreButArrogant]

I've had a problem with these cheap Chinese-made solar garden lights where the clear plastic covering the solar cell clouds or yellows with (presumably) exposure to strong UV light. This is happening at our house in Las Vegas.

My thought was to spray the plastic covering with a UV protectant, like 303 Aerospace Protectant (or any other automotive plastic trim protectant), to help block UV. However, I was concerned that the solar cell might be absorbing light in the UV spectrum to produce electricity. This chart: Spectral Response | PVEducation makes me think that anything below 400nm doesn't get converted to electricity, so a UV blocking coating won't affect the cell's performance.

Anyone else had this problem and try to solve it?

[MediocreButArrogant]

After a little more digging around, I found that people are using 303 Aerospace Protectant on solar garden lights. Another product people use are the brush-on UV coatings for auto headlight restoration. This got me thinking that an even better product for UV protection might be the silca-based plastic and trim restorers that I already have (Gtechniq C4 and CQuartz DLux, pricey boutique detailing products but they really work as advertised). They certainly last longer than regular plastic dressings (a year easily for the silca-based coatings, vs a couple months if you're lucky for the plastic dressings). Even if the UV protection is not as high, the fact that they need infrequent reapplication might make them a better choice.