If you want to read about a low-tech approach to solar cells invented — and forgotten — 40 years before Bell Labs announced the first practical silicon solar cell, we can’t promise the website, Low Tech Magazine, will be available. Apparently the webserver it is on is solar-powered, and a disclaimer mentions that it sometimes goes offline.
The article by [Kris De Decker] tells of George Cove and includes a picture from 1910 of the inventor standing next to what looks suspiciously like a solar panel (the picture above is from a 1909 issue of Technical World Magazine). His first demonstration of the technology was in 1905 and there is a picture of another device from 1909 that produced 45 watts of power using 1.5 square meters with a conversion efficiency of 2.75%. That same year, a new prototype had 4.5 square meters and used its 240-watt output to charge 5 lead-acid batteries. The efficiency was about 5%.