Energy is the basic requirement for all developed countries. All countries cannot be stabled economically without producing extra energy. Transparent solar panels are the most profitable and environmental friend source of energy for homes and industries. In order to obtain solar energy from solar panels, a large space is required as many solar cells are held together to produce high voltage that is a problem in the present age. This problem is solved by transparent solar cells in which any sheet of glass is turned into a photovoltaic solar cell. These cells provide power by absorbing and utilizing unwanted light energy through windows in buildings and automobiles, which leads to efficient use of architectural space. A Transparent solar cell can be fabricated by approximately nine technologies.
Some countries like Japan, the USA, India, and Germany got success up to some extent in the fabrication of transparent solar cells. Less than 80% transparency is achieved currently which is a better achievement. There are six types of transparent solar cells given as;
- Thin-film photovoltaics (TPVs)
- Near-Infrared transparent solar cell
- Polymer solar cell (PSC)
- Transparent luminescent solar concentrator (TLSC)
- Perovskite solar cell
- Electrophoretic deposition (EPD)
Thin-film photovoltaic is one of the prolific technologies and fabricated by different methods. Some methods depend on fabrication and others are depending on deposition techniques. Thin-film photovoltaics is a thin film ranging from nanometers to tens of micrometers. Thin film technology reduces the cost of solar cells in the market. The transparency increases by reducing the thickness of the film. The cheapest solar cell can be prepared and some parts of light energy are observed to convert into usable energy but in case of transparent solar panel light, the light is totally transparent. To overcome this difficulty we will discuss both partially and fully transparent solar panels one by one.
Photoelectric Effect (Solar Panel)
It is a process of which solar energy is directly converted into light energy. The current produce during this process is called photoelectric current and this phenomenon is called the photoelectric effect. Different devices used for such processes are solar panels and solar plates. These devices provide direct current. This is the cheapest source for producing energy.
Partially Transparent Solar Panels
Partially transparent solar panels absorb only 60% of the sunlight falling on the surface and the efficiency of this panel is 7.2% while the efficiency of a conventional photovoltaic panel is 12%. The reason for reducing efficiency is clear as only 60% light is absorbed and 40% is transmitted. This efficiency can be improved by adjusting a balance between transparent and absorbed light. A German company Heliatek GmbH has manufactured partially transparent solar panels with an efficiency of 7.2 %.
Fully Transparent Solar Cells
The transparent panels are suitable for some methods but these panels are not suitable for transparent windows. Fully transparent panels do not absorb visible part of sunlight but according to research at Michigan State University specific invisible wavelengths like ultraviolet light can be absorbed when an organic salt is used. This absorbed light is convert into electricity by the stripes of photovoltaic cells. The efficiency of a fully transparent solar cell is approximately 1%.
Near-Infrared Transparent Solar Cell
The Students of Michigan State University have succeeded in the development of fully transparent solar panels. This is an amazing achievement. There are countless applications of transparent solar panels in mobile electronics, automotive industries, and architecture. Transparent solar panels can be placed over a window or any other flat surface. According to Richard Lunt assistant professor of chemical engineering and materials science at MSU’s College of Engineering “We can tune these materials to pick up just the ultraviolet and the near-infrared wavelengths that then ‘glow’ at another wavelength in the infrared”