This question is very important question. Solar energy is the most required energy today. The fact is that this system is not so familiar with common people of India and hence, it is not famous in the market but still there is huge hidden requirement of this solar energy for each of every one. I am really not aware about this details of what kind of devices used for solar energy but we can see some of the information about this on the website http://en.wikipedia.org/wiki/Solar_cell. Also the supplier of solar energy devices are also capable to share the information on this question. Hence, we can directly visit the shop of solar energy vendor and clarify the queries before purchasing the device.