How light trapping increases the efficiency of solar cell?

​Improving the efficiency of the solar cells is the most challenging task for the renewable energy scientists.

   Today, the most efficient solar cell has efficiency around 22%

The one way to improve the efficiency of the solar cell is to limit the reflected light from the surface of the cell.

This can be done by anti-refection coatings but these coatings cannot prevent the transmission of light and it passes through the cell straight forward and get lost in the surroundings.

Another approach is the light trapping in the thin solar cells. It prevents both the reflection and transmission of the light, increasing the efficiency of the solar cells by light confinement (a photon bouncing back and forth many times within the cell) and increasing the absorption rate of the light within the cell.

The different strategies are adopted to increase the light confinement within the cell.

• The simple approach could be to reduce the reflection of light falling on the surface of the cell by changing the texture in such a way that it enhances the bouncing of light within the cell rather than to the surroundings.

The textured surface makes the incident light to bounce on the surface of the cell multiple times and hence increases the path-length of the photon.

It is possible to enhance the path-length up to 50 times the device thickness, indicating that the light bounces back and forth within the cell resulting in the light confinement and increases the efficiency of the solar cell.

You can see in the above picture that by altering the texture of the solar cell we can achieve multiple reflections within the cell, increasing the path-length of the photon and hence increasing the efficiency of the solar cell.

However, it is a matter of time that how well we can make this commercially viable.

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