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34 SOLAR POWER SYSTEM PHYSICS AND TECHNOLOGIES
similar to the monocrystalline manufacturing process and is sandwiched between glass
plates, which form the basic PV solar panel module.
Even though the process yields relatively inexpensive solar panel technology, it has
the following disadvantages:
■ Larger installation surface
■ Lower conversion efficiency
■ Inherent degradation during the initial months of operation, which continues over
the lifespan of the PV panels
The main advantages of this technology are
■ A relatively simple manufacturing process
■ Lower manufacturing cost
■ Lower production energy consumption
Thin-film cadmium telluride cell technology In this process, thin crystalline
layers of cadmium telluride (CdTe, of about 15 percent efficiency) or copper indium
diselenide (CuInSe , of about 19 percent efficiency) are deposited on the surface of a
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carrier base. This process uses very little energy and is very economical. It has simple
manufacturing processes and relatively high conversion efficiencies.
Gallium-arsenide cell technology This manufacturing process yields a highly
efficient PV cell, but as a result of the rarity of gallium deposits and the poisonous quali-
ties of arsenic, the process is very expensive. The main feature of gallium-arsenide
(GaAs) cells, in addition to their high efficiency, is that their output is relatively inde-
pendent of the operating temperature, and thus these cells are used primarily in space
programs.
Multijunction cell technology This process employs two layers of solar cells,
such as silicon (Si) and GaAs components, one on top of another to convert solar power
with higher efficiency. The staggering of two layers allows the trapping of a wider band-
width of solar rays, thus enhancing the solar cell solar energy-conversion efficiency.
Dye-Sensitized Solar Cells
Dye-sensitized solar cells (DSCs) are a class of solar cells that are formed by placing a
semiconductor between a photo-sensitized anode and an electrolyte, which have pho-
tochemical properties that provide charge separation by absorbing solar energy. This
class of cells is also referred to as Grätzel cells, the name of the inventor.
Even though these types of cells have lower conversion efficiency than the existing
thin-film and solid-state semiconductor-based technologies, owing to the lower cost of
