The most challenging approach of generating electricity from sunlight is hot carrier solar cells.
The hot carrier solar cells, which utilize selective energy contacts to extract light generated hot carriers from semiconductor regions.
Hot carrier solar cells convert their excess energy to heat into semiconductor lattice.
The optimizing both extraction energy and the bond gap of the absorber.
The hot carrier solar cell achieves very high efficiency.
According to ROSS and NOZIK the efficiency limit of 66% for a hot carrier conversion system is grater than an ideal thermal system 52%, and for a quantum system.
The chemical potential of a excited and is negative which reduces radiation losses, and permits a low threshold energy.