Inkjet solar cells are solar cells manufactured by low-cost, low-tech methods that use an inkjet printer to lay down the semiconductor material and the electrodes onto a solar cell substrate.
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This approach is being developed independently at various locations including the University of New South Wales, Oregon State University, and Massachusetts Institute of Technology.
History
The first case of printed electronics was seen in 1903 when Albert Hanson filed a patent for "printed" wire. After that the radio drove the industry of printed electronics forward. Until recently inkjet printers have not been used in the printed electronics industry. Industry has decided to move towards inkjet printing because of its low cost and flexibility of use. One of these used is the inkjet solar cell. The first instance of constructing a solar cell with an inkjet printer was by Konarka in 2008. In 2011 Oregon State University was able to discover a way to create CIGS solar cells using an inkjet printer. In the same year MIT was able to create a solar cell using an inkjet printer on paper. The use of an inkjet printer to make solar cells is very new and is still being researched.
How they are made
In general inkjet solar cells are made by using an inkjet printer to put down the semiconductor material and electrodes onto a solar cell substrate. Both organic and inorganic solar cells can be made using the inkjet method. Inkjet printed inorganic solar cells are mainly CIGS solar cells. The organic solar cells are polymer solar cells. First, the ink must be prepared. Generally the ink is composed of a metal salt mixture(CIGS) in the inorganic case. In the organic case the ink is a polymer fullerene blend. The ink is then printed onto a substrate which can vary. These materials are what creates the electric power from sunlight. In most cases more layers of other materials are deposited or the cell goes through another process to complete it. The entire process is done in atmospheric pressure and can use temperatures of up to 500C. Important factors for the efficiency of inkjet printed organic solar cells are the inkjet latency time,the inkjet printing table temperature, and the effect of the chemical properties of the polymer donor.
Advantages
The main advantage to printing solar cells with an inkjet printer is the low cost of production. The reason it is cheaper than other methods is because no vacuum is necessary which makes the equipment cheaper. Also, the ink is a low cost metal salt blend reducing the cost of the solar cells. There is very little waste of material in comparison to other methods like vapor phase deposition when using inkjet printers to lay down the semiconductor material. This is because the printer is able to create precise patterning with little waste. Some inkjet solar cells use the material CIGS which has more solar efficiency than the traditional silicon solar panels. Using CIGS makes it very important to have little waste due to how rare some of the materials in it are. This method is also environmentally friendly because it does not require the use of toxic chemicals to prepare the solar cell like other methods do.
Disadvantages
The efficiency of inkjet solar cells are too low to be commercially viable. Even if the efficiency gets better the materials used for the solar cells could be a problem. Indium is a rare material used in these cells and could be gone within 15 years according to our current usage. Another issue is creating a weather resistant ink that can survive harsh conditions.
Potential
In traditional solar cells the material that holds the photovoltaic material generally costs more than the material itself. With inkjet printing it is possible to print solar cells on paper. This will allow solar cells to be much cheaper and be placed almost anywhere. Paper thin solar cells or eventually direct 3D printing will allow to create solar cells on blinds, in windows, in curtains, and almost anywhere in the home. This is very promising and could be the future of solar power.