Question

what is the maximum efficiency of a solar cell? recall the temperature of the sun is 5600 K.

Answer 1

In physics, the Shockley–Queisser limit, also known as the detailed balance limit, Shockley Queisser Efficiency Limit or SQ Limit, refers to the maximum theoretical efficiency of a solar cell using a single p-n junction to collect power from the cell. more recent calculations give a maximum efficiency of 33.7% at 1.34 eV,  The limit is one of the most fundamental to solar energy production with photovoltaic cells, and is considered to be one of the most important contributions in the field.

The limit is that the maximum solar conversion efficiency is around 33.7% for a single p-n junction photovoltaic cell, assuming typical sunlight conditions, and subject to other caveats and assumptions discussed below. This maximum occurs at a band gap of 1.34 eV. That is, of all the power contained in sunlight (about 1000 W/m²) falling on an ideal solar cell, only 33.7% of that could ever be turned into electricity (337 W/m²). The most popular solar cell material, silicon, has a less favorable band gap of 1.1 eV, resulting in a maximum efficiency of about 32%. Modern commercial mono-crystalline solar cells produce about 24% conversion efficiency, the losses due largely to practical concerns like reflection off the front of the cell and light blockage from the thin wires on the cell surface.