Question

1 – How does the solar cell work? Why do different light sources affect the voltage?

2 – Discuss the efficiency of a TiO2-based cell vs. a TiO2/ZnO cell.

Answer 1

A solar cell is a sandwich of n-type silicon and p-type silicon . It generates electricity by using sunlight to make electrons hop across the junction between the different flavors of silicon . When sunlight shines on the cell, photons (light particles) bombard the upper surface. The photons carry their energy down through the cell.The photons give up their energy to electrons (green blobs) in the lower, p-type layer.The electrons use this energy to jump across the barrier into the upper, n-type layer and escape out into the circuit.Flowing around the circuit, the electrons make the lamp light.

Now,the light sources affects the voltage of the solar cell as the Larger the distance between the source and the solar cell ,the smaller amount of energy will be produced and hence voltage will be less this is because light spreads as soon as it leaves the source.

Also ,the shorter wavelength Light sources , that is,the more energy will have higher voltage then that of light sources at longer wavelength.