Solar Cell Structure

A solar cell is an electronic device which directly converts sunlight into electricity. Light shining on the solar cell produces both a current and a voltage to generate electric power. This process requires firstly, a material in which the absorption of light raises an electron to a higher energy state, and secondly, the movement of this higher energy electron from the solar cell into an external circuit. The electron then dissipates its energy in the external circuit and returns to the solar cell. A variety of materials and processes can potentially satisfy the requirements for photovoltaic energy conversion, but in practice nearly all photovoltaic energy conversion uses semiconductor materials in the form of a p-n junction.

The basic steps in the operation of a solar cell are:

=>the generation of light-generated carriers;

=>the collection of the light-generated carries to generate a current;

=>the generation of a large voltage across the solar cell; and

=>the dissipation of power in the load and in parasitic resistances.

Another Structure of a solar cells - function and working principle

Solar cells are structured in layers with different functions. The working principle is the same as in semiconductors. 

The main part of a silicon (Si) solar cell generating solar power is formed by two differently doped (n- and p-) silicon layers. A physical barrier is created between them along the p-/n- junction, with electrons and holes diffusing into regions of lower concentration.

This depleted region or space charge region can only be overcome with the help of photons i.e. sunlight.

To be able to channel electrones and holes and generate electric power, metal contacts need to be printed onto the front and rear side. Generally, a full aluminium or silver layer is screenprinted onto the rear. A thin grid forms the front contact keeping the impact on light entering the silicon cells as low as possible.

To reduce light reflection, a thin film of silicon nitride or titanium dioxide is coated onto the surface.

credit:http://www.pveducation.org/pvcdrom/solar-cell-operation/solar-cell-structure

    AND http://www.renewable-energy-concepts.com/solarenergy/solar-technology/si-solar-cell-structure-function.html