Solar farms use plastic ones at least in some installations in the south run by overseas corporations - silicon ones are too expensive.
Your home panels are likely silicon. There’s a difference.
First off, it doesn’t matter, plastic takes decades to break down. Secondly, plastic is not replacing silicon because plastic is not a conductive material like silicon is. There is some research into other materials than silicon being used, but so far are not commercially produced. Those could have some organic materials in them that can contaminate soil. Sorry, no matter how much you want solar panels to break open and contaminate the ground underneath it’s just not happening.
I understand some of the large farms have series of pipes circulating different chemicals, including water in some cases, for cooling effects. But this is different than what you are describing. Perhaps you misunderstood. Or maybe whoever you got the info from was wrong or just flat out lying.