Currently, solar technologies rely on cells made from silicon. The process of manufacturing is expensive and time consuming. More and more engineers and scientists are looking into the so call "spray-on" technology which resembles the process of inkjet printer. You simple "print" the solar cell out. This technology could make solar panel relatively inexpensive, easy-to-manufacture.
Below are few "spray-on" technologies:
(1) Researcher Jillian Buriak and her team at the University of Alberta have designed nanoparticles that absorb light and conduct electricity, using phosphorus and zinc. Both materials are more plentiful than scarce materials such as cadmium and are free from manufacturing restrictions imposed on lead-based nanoparticles. This new technology could be mass-manufactured using simple methods, such as roll-to-roll printing or spray-coating.
(2) Researchers at the Australian National University (ANU) are working in collaboration with solar company Spark Solar Australia and Finnish materials company BraggOne Oy investigating solar cells made from quantum dots. Quantum dots is a nanocrystal made of semiconductor materials that are small enough, in the size of ~ 0.000001 mm, which displays quantum mechanical properties. These quantum dots are mixed with a conducting polymer to make a plastic. Spray-on solar panels composed of this material can be manufactured to be lighter, stronger, cleaner and generally less expensive solar cells.
(3) Professor David Lidzey and his team from the University of Sheffield’s Department of Physics and Astronomy and the University of Cambridge have created a method of spray-coating a polymer (layman term plastic) based photovoltaic active layer by an air based process – similar to spraying regular paint from a can – to develop a cheaper technique which can be mass produced.
(4) Mitsubishi Chemical Corp. has developed a solar spray-on technology based on carbon compounds. When dried and solidified, the material would behave like semiconductors and generate electricity when exposes to light. Currently, Mitsubishi has achieved a conversion rate of 10.1%, half of what you can get from si panel.
The major issues encountered by most of the "spray-on" technologies are lower cell efficiency, scale-up production, and long-term reliability. It will still be a while before it can be a mainstream technology.