I was reading an article on scientists that discovered the blackest substance know to man. Scientists Invent Blackest Black
I thought this type of substance would be great for using in a solar cell. Then I started to think about what it means it be black. The substance, carbon nanotubes, absorb all the photons of energy and do not radiate back anything (in the visible spectrum), what happens to the energy? Is it radiated in other nonvisible wavelengths (like heat), converted to mechanical energy (molecule rotational or vibrational energy) or somehow absorbed by the C-C bonds to another higher energy levels? Enough though I don't want to bother this great scientists, I will try and send this question to the discovers of the substance. I am just curious. If I get a response, I will share it with askmehelpdesk.com.

Please don't bother these busy scientists with your question that is answered in elementary physics classes.

You will find many many articles online and in physics text books about black-body radiation, it's one of the most fundamental concepts in astrophysics.

Black body - Wikipedia, the free encyclopedia

What happens to the energy?

It's absorbed into the vibrational (in this case C-C bonds) and rotational energy levels of the substance.

The substance, carbon nanotubes, absorb all the photons of energy and do not radiate back anything (in the visible spectrum), what happens to the energy?

Well, although it may be temporally absorbed otherwise, in the end everything is radiated back, unless used for other purposes.
If you get a response, I am interested to hear their response!