لخّصلي

Finally, the charge carriers are extracted from the solar cells with electrical contacts so that they can perform work in an external circuit (Fig.Thus, the maximal energy conversion efficiency of a single-junction solar cell is considerably below the thermodynamic limit.This single bandgap limit was first calculated by Shockley and Queisser in 1961 [2These two mechanisms alone amount to the loss of about half the incident solar energy in the conversion 24 Solar Energy process [26]. 3.2 ?).3.1 (b).

Finally, the charge carriers are extracted from the solar cells with electrical contacts so that
they can perform work in an external circuit (Fig. 3.2 ❹). The chemical energy of the electronhole pairs is finally converted to electric energy. After the electrons passed through the
circuit, they will recombine with holes at a metal-absorber interface,
The two most important loss mechanisms in single bandgap solar cells are the inability
to convert photons with energies below the bandgap to electricity and thermalisation of
photon energies exceeding the bandgap, as illustrated in Fig. 3.1 (b). These two mechanisms alone amount to the loss of about half the incident solar energy in the conversion
24 Solar Energy
process [26]. Thus, the maximal energy conversion efficiency of a single-junction solar cell
is considerably below the thermodynamic limit. This single bandgap limit was first calculated by Shockley and Queisser in 1961 [2