If you walk past a solar farm, the odds are overwhelming that what you are looking at is crystalline silicon — the bluish, wafer-based panels that dominate the global market. First Solar is the big American exception: it makes a fundamentally different kind of panel, and its Form 10-K for fiscal 2021 is where the rationale is spelled out.
The mainstream technology starts from silicon. You grow and slice crystalline silicon into wafers, build cells from them, and assemble cells into a module. It is a mature, enormously scaled supply chain, and it delivers high efficiency — a lot of watts per square meter. Its downside is that it is a multi-step, materials-heavy process, and that supply chain is concentrated in a few places.
First Solar's approach is thin-film. Instead of silicon wafers, it deposits extremely thin layers of a semiconductor — cadmium-telluride, or CdTe — directly onto sheets of glass. The films are a tiny fraction of the thickness of a silicon wafer, hence 'thin-film.' The manufacturing is more like a continuous coating line than a wafer factory, which is central to the cost argument.
The honest trade-off is efficiency. Per unit of area, CdTe thin-film has historically delivered lower peak efficiency than the best crystalline silicon — you need a bit more land for the same nameplate. First Solar's counter-arguments, which run through the filing, are threefold: the manufacturing can be cheaper and faster at scale; the technology tends to hold its performance better in high heat, so it can produce strong real-world energy in hot climates; and the company controls its own vertically integrated production rather than depending on the silicon supply chain.
That last point — a self-contained, largely domestic supply chain — is increasingly a strategic asset, not just an engineering footnote. The filing frames First Solar's manufacturing footprint as a differentiator at a moment when buyers and policymakers care about where panels are made and how resilient the supply is, not only about cost per watt.
None of this makes one technology simply 'better.' It makes them suited to different priorities — maximum efficiency on constrained land versus low-cost, heat-tolerant, supply-secure energy at scale. To understand which bet First Solar is actually making, read the technology discussion in the 10-K, retrievable through services like EdgarBeast, rather than a one-line spec comparison.