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Basically silicon PV panels (the kind universally used now) are significantly less toxic than table salt and basically nearly else in your house.

The PV cells themselves contain silicon, aluminum, silver, and trace amounts of phosphorus and boron, and now sometimes gallium. Upon exposure to air or water the silicon surface passivates by forming a layer of amorphous silicon dioxide, which protects the silicon from further corrosion even in strong acids and room-temperature strong bases. Amorphous silicon dioxide is also used as an inert filler in pills, an abrasive in toothpaste, and one of the two main ingredients in simethicone, a treatment for gas pains. If you ground up the PV cells finely enough you could add them to your food with no ill effects.

Most of the mass of the panel is glass, which is also mostly amorphous silicon dioxide with small amounts of calcium and sodium oxides. This you could also add to your food in powder form with no ill effects, contrary to urban legends about ground-glass poisoning.

Gluing the PV cells to the glass is normally EVA, poly(ethylene-vinyl acetate). This is the material crafting hot-glue sticks is made from, as well as flip-flops, mouthguards, yoga mats, and those soft foam toys for kids. Less well known is that it's used as an extended-release drug delivery vehicle in implants: the drug slowly leaches out of the plastic inside your body, while the plastic remains unchanged. It has no known adverse effect on human health.

Sealing the back of the modules is a thin layer of, typically, polyvinyl fluoride (tedlar), which is also relatively biologically inert, but not to the same extreme as the rest of the materials. It's commonly used for raincoats and whiteboards. Hydrofluorocarbons tend to be of relatively low toxicity, but it's not thoroughly biocompatible in the same way as its cousin PVDF, or as EVA and silicon. Some panels are instead made with polypropylene or polyethylene terephthalate, which are as extremely nontoxic as the other materials.

The cells' electrical connections are soldered together with solder. Traditionally this was lead and tin, which does leach lead, though very slowly. Nowadays lead-free solder is used, typically consisting of tin and silver. This is another thing you can eat freely, although there might be traces of flux left from soldering.

The frames are normally made of aluminum, which is extremely nontoxic.

So, no heavy metals except tin and silver, which are nontoxic. Except that silver is toxic to bacteria.

There have been some experiments with nickel/copper plating to reduce the amount of (costly) silver used; I'm not sure if these are in production. Although nickel and copper are pretty safe, they're not nearly as astoundingly nontoxic as the other materials listed above. If you eat chunks of copper you will get sick.

Some thin-film panels have been made with more toxic materials like cadmium, selenium, copper, and tellurium, but they have mostly been driven out of the market by silicon PV cells. The total amount of these materials was small, but it's been found that they could leach out in an acid landfill. But they're not present in silicon cells.

So basically everything you have in your house is way more toxic than solar panels. Latex paint? Toxic polymers. Steel knife? Potential for iron poisoning. Concrete? There's substantial trace levels of many heavy metals in the cement, and it's basic enough to burn your skin, plus there are probably superplasticizer additives that are more toxic than anything listed above. Books? Likely still have trace levels of dioxin from bleaching the paper, plus most of the color inks are more toxic than anything in a solar panel. Polyurethane dishwashing sponge? Polyurethane is definitely not a thing you should eat. Foam cushions in furniture? In addition to polyurethane those contain halogenated fire retardants that are suspected of causing mass endocrine disruption. Wood cutting board? Most woods contain natural biocides to keep from rotting. Coca-Cola? Not only is the fatal dose of phosphoric acid relatively small, and it's keeping you from absorbing calcium, but also lots of the flavoring compounds are enormously more toxic than silicon and glass. Sand? That's crystalline silica, which causes silicosis and lung cancer if inhaled, unlike the amorphous silica we're talking about above. Stainless steel? Nickel can sensitize you over time and cause serious inflammation.

The only things I can think of in a regular person's house that are probably less toxic than solar panels are air, water, plaster, clay, glass, and aluminum cans.