ABSTRACT
At present, solar energy is considered the most promising renewable power source due to its easily exploitable, inexhaustible, quiet, and adjustable to
enormous applications. Every day, the Sun shines on the Earth and providing around 3 x 1024 J of green energy per year, which exceeds by a factor of 104 the present global population consumption. A simple calculation leads self-evidently to the conclusion that covering only around 0.1% of the Earth’s surface by means of energy conversion devices having an efficiency of about 10% would satisfy the present global energy needs. These encouraging numbers are inducing the scientific community to make even greater efforts towards the direction of improving solar energy conversion technologies as well as proposing new, intriguing solutions. The sun can provide the ultimate solution to the challenge of a sustainable energy supply. In one hour, the earth receives 13.6 TW from the sun, more than what we currently consume in a whole year (13 TW) [1]. The conversion of solar radiation to electrical energy (photovoltaics) has become more and more important, because sunlight is a clean and limitless energy source compared to the traditional fossil energy sources.
