Different types of solar cells and their efficiency
October 22, 2019
Solar panel modules differ mostly in their:
Type – monocrystalline, polycrystalline, thin-film
Power output (also known as ‘power rating’ or ‘rated power’; here it is denoted in watts-peak Wp instead of in usual watts) – between 10 Wp and 300 Wp Output voltage – 12 V, 24 V, 48 V or 60 V Size and weight – commonly 1.6 x 0.8 meters, or 5.25 x 2.62 feet.
Monocrystalline solar panels
Monocrystalline solar (photovoltaic) modules are the most efficient but also the most expensive ones. They come in blue or black in color.
Only fewer solar modules you need to produce a certain amount of power, as the efficiency is higher. Normally, if there is not enough free space on your roof, you choose modules of higher efficiency.
Monocrystalline panels are produced by reliable and proven technology. You can still find monocrystalline panels producing power with only 20% power degradation compared to initial power output after more than 40 years of work.
Advantages of monocrystalline modules:
lesser number of modules for a given power output
less space for installation
least power degradation when compared with other types
Polycrystalline solar panels are slightly less efficient and cost 30-50% less than monocrystalline ones when used to produce the same amount of power.
Polycrystalline modules have a lifecycle of about 25 years. The practice has shown, however, that polycrystalline solar panels installed more than 25 years ago are still perfectly operational.
Polycrystalline cells are typically blue and can be easily distinguished by their multifaceted, kind-of-shimmering appearance.
Thin-film (amorphous) modules
Thin-film modules are the least expensive modules with the lowest efficiency – usually twice less than the monocrystalline panel’s efficiency. This means that in order to generate the same amount of power, you need twice more thin-film modules than monocrystalline ones.
Thin-film modules have a dark surface – usually colored in brown, gray and black. Thin-film modules are the one commonly used in solar calculators.
Some general studies on the latest solar module technology
Crystalline (mono- or poly-) solar modules are the most common type for home and business photovoltaic systems. Crystalline modules come in a variety of sizes and shapes, rectangular ones, however, are the most common.
In all cases, you should ask solar vendors to show you a number of solar installations to see how every solar panel array is matched to the roof and the building from an aesthetical point of view.
Solar panels have a lifetime of about 20-25 years, with about 80% of their rated power guaranteed within such a period. Every solar panel has nominal power rated in ‘watts-peak’ (Wp) or ‘kilowatts-peak’ (kW). Here is a comparison between solar panel efficiency according to the area needed to install a solar panel of Nominal Power = 1 kWp:
Solar Cell material
Area needed for
13 – 15%
7 m² (75 sq.ft)
12 – 14%
8 m² (86 sq.ft)
6 – 7%
15 m² (181 sq.ft)
Thanks to the advancement in thin-film CdTe solar cell technology, however, commercially offered CdTe thin-film solar cell panels have recently reached an average efficiency of 11.4%.
The average efficiency of most common thin-film modules is 5% and one of the monocrystalline modules is 12%. This fact, combined with the lowest manufacturing cost of this type of solar modules ($ 0.75 per W), is a promising advancement in solar technologies.