2. Spectrum splitting and concentrating system
Optimal conversion efficiency from a PV system can be achieved
by directing different parts of the solar spectrum onto solar cells
with matching energy absorption bands. There are two schemes
for proper utilization of entire solar spectrum. Either by stacking
the cells on top of each other in an optical and electrical series
connection commonly called a cascade/tandem/multijunction cell
or placing next to each other in a parallel connection [32]. In tandem
cell, sunlight is incident on the largest band gap cell where
short-wavelength photons excite electrons to a higher potential.
Light not absorbed by the upper cell is transmitted to the second
cell of a smaller band gap value, where longer wavelengths will