Perovskite-Silicon Tandem Module Lifetime: The Top Cell Sets the Limit

… more less Perovskite-silicon tandem module lifetime is set by the subcell that wears out first. In a two-terminal stack the two cells are in series. The one with less current sets the output of both. Silicon panels often carry warranties of about 25 to 30 years, and silicon fades slowly. The perovskite top cell tends to fade faster under heat, light and moisture. As it fades, it makes less current, and it pulls the whole stack down with it. Past a point the tandem can make less power than the silicon cell would make on its own. That means the extra cost of the top layer is lost. So the key test is not the starting efficiency. It is whether the perovskite holds its output for as long as the silicon does. To judge a claim, look at the T80, the time to fall to 80 percent of start, and the test used: light, heat, damp heat and outdoor runs. Then compare it with the decades a silicon panel is expected to last. Today most outdoor data on tandems cover only a few years at most, far short of a full panel life. So long-life claims rest mostly on fast lab tests. After this Concept you can explain why the top cell limits a tandem's lifetime and judge whether a tandem's stability data support its long-term value.