for solar panels you need silicon with 99.99% degree purity. (10^-4 parts of impurities) you don’t get that easily with medieval peasant technology. you need a high-tech vacuum chamber and some chemical to do the purification for you, and also repeated heating/cooling down. Then you need to spray the heated gaseous silicon on a surface and let it cool down slowly so it crystallizes …
for solar panels you need silicon with 99.99% degree purity. (10^-4 parts of impurities) you don’t get that easily with medieval peasant technology. you need a high-tech vacuum chamber and some chemical to do the purification for you, and also repeated heating/cooling down. Then you need to spray the heated gaseous silicon on a surface and let it cool down slowly so it crystallizes …
I don’t think we’d be back to middle ages tech, it would be more like industrial revolution right?