Nearly all energy in one form or another can be traced back to solar energy, and it is harness in many different ways. Solar cells are the most direct way to convert incident solar radiation into electricity, this process is also known as photovoltaics. Solar cells produce no pollution, noise, and do not contain any moving parts, allowing them to be tough, reliable, and long lasting. The natural light that we enjoy from the sun and see every day is only a fraction of the total energy emitted by the sun incident on the earth. The visible portion of sunlight is from just a small portion of the electromagnetic spectrum. 
Fig. 1. The solar spectrum in the electromagnetic spectrum, as a function of wavelength, frequency, and energy. 
Due to the nature of solar energy, the two components required to have a functional solar energy generator are a collector and a storage unit. The job of the collector is just that, to collect the radiation that falls on it and converts a fraction of it to other forms of energy, usually electricity. The storage unit is necessary due to the inconsistent nature of solar energy; weather and time of day effect the amount of radiation that can be received. The storage unit holds excess energy produced during the periods of maximum productivity, and releases it as needed during times of low energy production. The most common type of collector is the flat plate collector, an array of solar panels arranged in a plane. The output of these collectors is directly related to the size, cleanliness and amount of solar radiation they are exposed to.  The photovoltaics available on the market today are only about 15% efficient  nut advances in technology have recently produced a solar cell with a staggering 44.7% efficiency.  At today’s 15% solar technology is not worth investment from power companies, but if the new technology can maintain its efficiency in the uncontrolled environment of the real world, and does not have a tendency to break down, the technology is more than economical enough for power companies to invest in solar energy.
Structure of a Solar Cell
The simplest photovoltaic devices consist of two materials that differ in electronic properties (one electron-rich and the other electron-deficient). These materials are placed between two electrodes forming the front and rear contacts of the cell. When light strikes the two dissimilar materials, electron hole pairs are generated. These photogenerated charge carriers are separated at the interface between the two materials by an internal electric field, resulting in the generation of electrical power. The light that hits the solar cell produces both a current and a voltage to generate electric power. A material in which the absorption of light raises an electron to a higher energy state is required, along with the movement of this higher energy electron from the solar cell into an external circuit. The energy from the electron is then dissipated in the...