Aside from silver for contact wires, PV panels are made (or could be made) with mundane materials available in essentially unlimited amounts. The total mass flowing through new PV panels each year if the US were fully solar powered would be much less than the volume of mundane material flowing through the system already. For example, the EPA estimated that in 2018 the US generated 600 million tons of construction and demolition waste (of which 143 million tons went to landfills.)

https://www.epa.gov/facts-and-figures-about-materials-waste-...