Solar Cells... an Analysis

            The Solar Cell. Probably one of the most influential devices for the future. We do not think about it as the push for alternative energy is not so great in current times, but it is considered to be a sustainable source for the future. There are several different designs and trials for solar cells. The type that is beginning to emerge from the pack is thin film solar panels. While being lightweight and thin (of course), they can be mounted to roofs or even integrated into roofs. They have a much lower chance of being blown off in storms, are rugged in design, and are becoming more and more efficient.

            The working behind solar cells is pretty interesting (for simplicity). Solar cells work off of something called the photovoltaic effect (PVE). As light hits a certain material, electrons are ejected in a vacuum and picked up by an electrode. Electricity is then generated and can be used when the circuit is completed. The traditional structure of a thin film cell is shown below. As you can see, the cell is layered with multiple junctions to make it more efficient by collecting as much of the light spectrum as possible. As light travels from top to bottom, difference spectrums of light are collected. A coating is also applied to the top to keep the light in as long as possible so that the cells have more to absorb. Also, by use of the Seeback Effect, heat energy also mimics a similar effect to the solar cell that light has. Thermal energy can shoot off electrons onto the electrode as well. While this coating traps the light, it traps the heat energy as well.

            When we view a solar cell, we do not see all of these layers, especially in thin film when the layers are nanometers apart. In the outdoor environment, we see the case (vacuum) that the actual cell is hiding within. The cell covering also has some coating to keep light inside. It is usually constructed of non-reflective glass to transfer as much light as possible into the cell and keep it there. This process is quite amazing and research behind it is endless. Many elements display the (PVE), but certain elements are better than others, others are worse, and some do display this effect. Elements can be combined in a plethora of combinations to create the highest efficiency possible. No solar cell has ever reached 100% efficiency, even 50%. Most solar cells tend to stick around 20%. There is a lot of potential still there. The statement that is made for the future is that solar cells exist and can be modified for the better. They are constantly becoming more credible and research is being conducted to solidify their role in the world today. First Solar is a company that is on the pioneering edge for thin film technology and despite financial trouble in recent years, they are still on the forefront. Many companies are attempting to invest and research in all sorts of types, but the world is not quite ready for a dramatic switch from fossil fuels. As solar cells become better and better, they will help with the transition to a cleaner generation.