PV Gap

Betty Said:

what is the best efficiency of solar-to-electricity energy conversion that one has achieved till now?

We Answered:

Efficiency of photovoltaic energy depends on many factors:

- Wavelength of Light: When light strikes the surface of a solar cell, some photons are reflected and do not enter the cell. Other photons pass through the material, some are absorbed but only have enough energy to generate heat and don't create charge carriers

- Recombination: Charge carriers—which are electrons and holes—in a solar cell may inadvertently recombine before they make it into the electrical circuit and contribute to the cell's current.

- Natural Resistance: The natural resistance to electron flow in a cell decreases cell efficiency.

- Temperature: Solar cells work best at low temperatures, but solar cells work with sun light wich increases its temperature.

- Reflection: When light arrives to any surface, a percentage of light will be reflected. A cell's efficiency can be increased by minimizing the amount of light reflected away from the cell's surface.

- Electrical Resistance: Larger electrical contacts can minimize electrical resistance, but covering a cell with large, opaque metallic contacts would block too much incident light.

- Quantum Efficiency: is the ratio of the number of charge carriers collected by the solar cell to the number of photons.

because of that silicon solar cell efficiencies vary from 6% for amorphous silicon-based solar cells to 30% or higher with multiple-junction research lab cells (gallium arsenide or indium selenide).
Solar cell energy conversion efficiencies for commercially available mc-Si solar cells are around 12%.