Solar Power Information

Solar energy is existing in abundance around us. The trouble is how to harness a substantial portion of it for human use. How to raise the efficiency bar of solar transition into electricity? Scientists are endlessly engaged in finding a way out for this problem. Lately scientists at the Kyoto Institute of Technology have deviated from the regular path and tried to trap the visible as well as invisible rays of sun for electricity. They tried to produce a new photovoltaic cell that can capture visible, infrared and ultraviolet light of the sun. The team now thinks that this photovoltaic will be extremely efficient for solar power transition.

In March, 2010 a meeting was held by the Japan Society of Applied Physics. In this meeting a research group from the Kyoto Institute of Technology talked about their new photovoltaic cell that is capable of generating electricity not only from visible light, but from ultraviolet and infrared light as well. The research group is headed by the associate professor Saki Sonoda. The research group presented a 90-minute lecture on the cell under the title “Nitride Semiconductor Added With Transition Metals as a Photoelectric Conversion Material for Ultraviolet, Visible and Infrared Lights ~ In the Aim of Realizing the Next-generation Super-efficient PV Cell With a Simple Element Structure.”

Saki Sonoda is quite hopeful that his team’s work would lead towards a more effective PV cell that can be single-junction instead of the more conventional multi-junction. A multi-junction PV cell has multiple thin films of varying absorption capabilities. This will help in capturing the entire spectrum of light. But with a single-junction cell all that light can be absorbed using a single junction cell.

These new PV cells were comprised of gallium nitride (GaN) semiconductor. This new photovoltaic cell is produced by ‘doping’ a wide bandgap transparent composite semiconductor i.e. gallium nitride (GaN) with a 3d transition metal such as manganese. Gallium belongs to the family of scandium, titanium, vanadium, chrome, iron, cobalt, nickel, copper, and zinc. Sonoda explained that his team has gone for those additive elements. He said that even aluminum nitride (AlN), which has a very large bandgap, can perhaps have an absorbing region in the visible light range,

If we view the stats we can see that the short-circuit current density of the PV cell is about 10?A/cm2, which is nearly 1/1,000 that of a normal crystalline silicon PV cell. Sonoda explained that typically the cell and electrodes are separated, therefore the electric resistance of the p-type GaN connecting them is very large. Now we can hope that the findings of the research group are anticipated to pave the way to a GaN-based PV cell with a entirely different mechanism.