Black silicon photodetector breaks the 100% efficiency limit (opens in new tab)

When they say that the photodetector achieves 130% efficiency, red flags pop up for anyone trained in science. Is this device creating energy ex nihilo -- like a perpetual motion machine only more so?

It turns out what they mean is that each photon impinging on the device produces, on average, 1.3 electrons. So there is not an explicit claim from an energy perspective that the device is more than 100% efficient.

But it does raise the question: Could this technology be used to significantly boost the efficiency of solar cells? The article does not address that.

> earlier been considered as the theoretical maximum

So... Was the theory (quantum electrodynamics) wrong?

> Aalto University researchers have developed a black silicon photodetector that has reached above 130% efficiency. Thus, for the first time, a photovoltaic device has exceeded the 100% limit, which has earlier been considered as the theoretical maximum for external quantum efficiency.

130% seems really interesting. Is it really just the color change?