If only there was a cheep plentiful energy source that provided 24/7 electrical generation.

@slowburn so kind of avian power source that I'm not aware of ?

cheep=cheap Spell check use to catch that. Even mild dyslexia is a serious pain.

Thus proving that heat really can flow from a cooler to a hotter body, after all. Right?

All energy is solar energy It will be so good for the long term prospects of the human race, when we are able to skip the prehisoric middle man.

What is so wonderful, clean, clear, and inspiring about this article is that EFFICIENCY is discussed and honored and declared.
Not so about those 3 bladed fans that are extremely low efficiency and living symbols of the lemming instinct and insanely bum engineering. No they really aren't symbols of hope for humanity.
And the Betz limit of 59% efficiency was hit 32 years ago and ignored by every second idiot in the wind energy field. Flying ain't the answer.

Ralph: Not really. What this is doing is overcoming a limitation of bulk semiconductors using double absorption - something that happens in nature, just not frequently.
Heat can flow from a cooler to a hotter body, it just requires energy to make it happen reliably. If you look up "Maxwell's Demon" and "Peltier devices" you should get a pretty good look at an interesting way we do flow hear from cold to hot.

Dont worry soon we will break the 40% barrier lol been hearing that since the 80s remember that show beyond 2000? We are beyond 2000! Where is my mr fusion? I want to go back to future

This is a great approach to solve the problem of utilizing long wavelength light with out underutilizing the sort wave photons. To be practical a solid state version needs to be developed. One problem I see from the photograph is the absorption efficiency. The test sample of the fluid is much thicker than what could be economically used with photovoltaic cells.
This defiantly not an example of heat flow from cold to hot. The energy level of a single yellow photo is much less than the combined energy of two red photons. The "concentration" of the energy is allowed by thermodynamics because wast heat is also created.

Great News for Solar Panels!
I hope this new idea can be applied in a very thin weather proof coating.