Stanford University researchers have built a small solar panel prototype to generate energy day and night.

It works like a classic solar panel and transforms the sunlight into electricity in the daytime. At night, an embedded thermoelectric generator (TEG) “harvests electricity from the temperature difference between the PV cell and the ambient surrounding,” according to the paper published in Applied Physics Letters and spotted via TheDailyBeast.

The technique works by capturing daytime heat into a heatsink. Then, when this energy is naturally radiated back into space, some of it can be captured by the TEG and a unique material that can capture thermal wavelengths.

The concept isn’t new, as we’ve published about Anti-Solar Panels before. However, the quantity of energy gathered at night is significantly higher than in previous attempts, making the technology one step closer to being useful in the real world.

That said, many challenges remain. First, the power generated at night is only 50 mW/m2 compared to ~1000 W/m2  for a standard solar panel (note that we went from milliwatts to watts). Secondly, the heat will cool down relatively quickly, translating to a decaying amount of electricity produced.

The technology is exciting and could probably be used in low-power applications or places where a reliable heat source is available. Of course, we still have decades of potential research to optimize this method further.

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