Developments in thin film solar panels have been accelerating in recent years; the attraction being the possibility of using less materials in production, therefore decreasing costs, and also allowing for flexibility so a solar panel could be affixed to practically any surface.
The Javey Research Group at the Laboratory for Nano Materials and Electronics at Berkely have been working on highly regular, single crystalline nanopillar (NPL) arrays of optically active semiconductors on aluminium substrates which are then configured as solar cell modules.
The researchers have demonstrated a solar cell structure that incorporates 3D, single crystalline n-CdS (Cadmium Sulfide) nanopillars, embedded in polycrystalline thin films of p-CdTe (Cadmium Telluride), to enable high absorption of light and efficient collection of the carriers.
In the design,: the material surrounding the pillars absorbs light and creates electrons, and the pillars transport those electrons to the electrical circuit. This design improves efficiency through allowing light to be trapped between pillars, increasing overall surface area and decreasing the distance electrons have to travel to the circuit, reducing energy loss.
The technology will enable the development of highly versatile solar modules on both rigid and flexible surfaces and allow the use of lower grade materials say the researchers. So far, materials conversion efficiency of ~12% with a device conversion efficiency of ~6% have been attained in the first generation solar modules.
Compatible with a wide range of semiconductor materials, the technology could potentially have a large impact in the development of very economical, efficient and light weight solar panels.
While a commercial product is a long way off, according to one of the researchers involved in the project, the cost could be 10 times less than crystalline silicon solar panels.
