I asked Claude 4 opus (thinking) re sunlight hitting a solar cell. Per Claude, the infrared wavelengths near the visible light wavelengths are the most efficient. But a big part of the sunlight is visible light, so a big part of the electrical energy from a solar cell is from visible light.

Also, per Claude, “When light strikes an n-type monocrystalline silicon solar cell, photons must have sufficient energy to promote electrons from the valence band to the conduction band across silicon’s bandgap. Silicon has a bandgap energy of approximately 1.12 electron volts (eV) at room temperature, which corresponds to a wavelength of about 1107 nanometers. This means photons with wavelengths longer than 1107 nm (energy less than 1.12 eV) cannot generate electron-hole pairs in silicon and pass through the material without contributing to electrical current. The relationship between photon energy and wavelength follows the equation E = hc/λ, where E is energy, h is Planck’s constant, c is the speed of light, and λ is wavelength. Using this relationship, we can understand how different portions of the solar spectrum interact with silicon. Infrared radiation spans wavelengths from about 700 nm to 1 mm, with energies ranging from approximately 1.77 eV down to 0.001 eV. Only the near-infrared portion up to about 1107 nm can be absorbed by silicon. Photons in the 700-1107 nm range have energies between 1.77 and 1.12 eV, making them ideal for silicon solar cells as they have just enough energy to create electron-hole pairs with minimal excess energy lost as heat. Visible light extends from 400 to 700 nm, corresponding to energies of 3.1 to 1.77 eV. All visible photons have more than enough energy to overcome silicon’s bandgap. However, the excess energy above 1.12 eV is largely wasted through thermalization, where hot carriers quickly lose their extra energy as heat. This fundamental thermalization loss limits the theoretical efficiency of single-junction silicon cells. Ultraviolet light, with wavelengths below 400 nm, carries energies above 3.1 eV. While UV photons are readily absorbed by silicon, their high excess energy results in significant thermalization losses. Additionally, UV photons are often absorbed very near the surface of the cell, where recombination rates are typically higher, further reducing their contribution to the cell’s output current. The high surface recombination and thermalization losses make UV photons particularly inefficient for silicon solar cells despite their high energy.”

I know re llm hallucination so I googled. I verified the energy formula and silicon’s energy gap.

Has Claude been right?