You might be interested in this: https://www.treehugger.com/solar-technology/solar-prototype-concentrates-suns-energy-glass-orb-boosts-pv-efficiency-35.html ht

You might be interested in this: https://www.treehugger.com/solar-technology/solar-prototype-concentrates-suns-energy-glass-orb-boosts-pv-efficiency-35.html https://www.treehugger.com/solar-technology/solar-prototype-... https://cleantechnica.com/2013/12/23/solar-ball-lens-improves-energy-efficiency-35/ https://cleantechnica.com/2013/12/23/solar-ball-lens-improve... Not solid glass, though (I don't know what it is, but I imagine there's an upper limit on size of solid glass spheres that can be made)...