There is no near/medium term limit to PV manufacturing volume from materials scarcity. The rarest material used in a typical crystalline silicon solar panel is

There is no near/medium term limit to PV manufacturing volume from materials scarcity. The rarest material used in a typical crystalline silicon solar panel is silver, part of the conductive pastes used to make electrical contacts on cells. Limits on silver availability could limit annual production rates with present mainstream designs. But manufacturers have found many ways to economize on silver use so that total PV silver consumption rose only slightly from 2011-2015 even as annual production volume rose 80%. SunPower uses plated copper for electrical contacts instead of silver pastes. Their modules are also the most efficient on the market. But the high efficiency and avoidance of silver come at the price of higher process complexity during cell manufacturing which leads to higher costs per watt of capacity. SunPower is at least an existence proof that you can produce modules at large scale, at high efficiency, from abundant elements. I expect other manufacturers to substitute away from silver too if increasing demand pushes silver prices up too high. Sometimes you'll see people claim that solar can't attain really large volumes because of dependencies on "rare elements." Those claims are probably referring to the tellurium in cadmium-telluride PV modules and/or the indium and gallium in copper-indium-gallium-diselenide modules. But you can safely ignore those worries because CdTe and CIGS together account for a very small share of the market; crystalline silicon dominates PV at over 90% share.