Solar panel efficiency over time

The conversion efficiency of a photovoltaic (PV) cell, or solar cell, is the percentage of the solar energy shining on a PV device that is converted into usable electricity.

Improving this conversion efficiency is a key goal of research and helps make PV technologies cost-competitive with conventional sources of energy.

Factors Affecting Conversion Efficiency 

Not all of the sunlight that reaches a PV cell is converted into electricity.

Solar panel efficiency percentage

In fact, most of it is lost. Multiple factors in solar cell design play roles in limiting a cell's ability to convert the sunlight it receives. Designing with these factors in mind is how higher efficiencies can be achieved.

• Wavelength—Light is composed of photons—or packets of energy—that have a wide range of wavelengths and energies.

  The sunlight that reaches the earth's surface has wavelengths from ultraviolet, through the visible range, to infrared. When light strikes the surface of a solar cell, some photons are reflected, while others pass right through.

  Some of the absorbed photons have thei

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