This was first proposed in a scientific study from 2019. Essentially, the idea is that the solar cell generates power from the heat it radiates at night. That study claimed a theoretical maximum efficiency of 4 watts/m2. A study released a few months ago claimed that it could instead generate up to 50 watts/m^2. The basic concept is apparently known as a thermoradiative cell, and has been described in other scientific studies like this and this.
(Image taken from the second study)
The second study has received quite a lot of attention in articles like this one.
However, I haven't found any questions about this here. Is this actually a practical idea? Could this really compensate for the traditional weakness of solar power?
