Each generation is facing new challenges and new opportunities. Fossil fuels have offered spectacular opportunities during the 20th century in the rich countries of the western world, but now mankind has to face the challenges arising from fossil-fuel exploitation. The availability of fossil fuels is not infinite and the world's growing thirst for oil amounts to almost 1000 barrels a second which means about 2 liters a day per each person living on the earth. Consequently, searching for clean and sustainable energy resources has become an urgent priority for the world. Solar energy is regarded as one of the perfect energy resources. Huge efforts were invested in developing highly efficient solar energy conversion technologies and the most prospective approach is converting solar energy into electricity. Solar energy is a clean, abundant and renewable energy source. The emerging photovoltaic industry has been growing rapidly in recent years.