Solar Cells with Built-in Cascade of Intrinsic Regions

Following the first principles of solar cell it is clear that the most efficient generation of electron-hole pairs happens by sunlight in intrinsic regions of any p-i-n photodiodes. In this excitement of junction there is most no electron/hole recombination. The unintentional doping in these intrinsic areas is minimal and electron-hole pairs are instantly separated by built in electric field in p-n junction. With that in mind we analyzed intensity flow photons in sun spectra selecting three stripes of color with average wavelengths λ
₁
= 512nm, λ
₂
= 596nm, λ
₃
=712nm. Using this analysis we designed heterostructured solar cell p-n junction CdS/CdSe with three intrinsic layers using mix of compound materials with energy gap E
₁
=2.42eV, E
₂
=2.08eV, E
₃
=1.74eV. Thus, the structure consists of top layer p-type CdS with concentration Na= 2×10
¹⁸
cm
^-3
followed by intrinsic 2μm thick layer i
₁
, 0.7μm thick i
₂
, 1.3μm thick i
₃
. Located at the bottom is 0.1μm thick n-type layer of CdSe with concentration Nd= 1×10
¹⁸
cm
^-3
. Using Silvaco design software we reached efficiency of the heterostructure to be 21.2%. Such efficiency combined with low cost of used materials present good option for manufactures to create profitable production.