This is absolutely untrue. The silicon is just the starting base, you still need to dope the cells, often with an arsenic compound (Indium-Gallium Arsenide, Gallium Arsenide, etc.)
In the EU and California, solar panels are exempt from RoHS requirements.
I used to manufacture solar panels for Sunspark Technology in California. You can't get the same kind of conductivity using tin bus ribbon without sacrificing usable cell area, as you need a wider, flat strip of tin, compared to lead. The newest "invisible bus bar" panels are using silver wire. These cells, when I worked there pre-COVID, were dumping ~11A at full light exposure. The inter-string bus bars were lead-coated copper, as were the string to junction box interconnect ribbons. 60/40 was used in the junction box. We manufactured panels for everyone, including Jinko, that behemoth of a solar corporation.
Solar panels very often have toxic stuff everywhere.