Climate change is one of the major environmental problems that affect our society. At present annually more than 40 billons Tons of greenhouses gases are exhausted to atmosphere and the tendency is to the rise; the main reason for this situation is the high and uncontrolled use of fossil resource in energy generation. Development an environmental, friendly and reliable energy technology is a necessity. Solar Energy emerged as possible solution to confront this problem. This technology permits a direct conversion of sunlight into electrical power without exhaust of both greenhouse gases and another polluting agent. Actually silicon technology is market leader in photovoltaic technologies, however since a pioneering (Gratzel & O’Regan, 1991) dye-sensitized solar cells (DSSCs) have become in one important and promising technology in photovoltaic field. DSSCs given born to new solar cells generation replaced classical solid-state homo and hetero-junction device by a new concept with a nano-working electrode in photo-electrochemical cell. This technology offers a very low cost fabrication and easy industry introduction prospective; furthermore efficiencies near to 10% AM1.5 for DSSCs have been confirmed. DSSCs consists of three main components: A dye-covered nanoporous TiO2 layer on a glass substrate coated with a transparent conductive oxide (TCO) layer, an redox electrolyte and a electrical contact deposited on conducting glass. Different parameters affect efficiency of the DSSCs: types of materials used as electrolyte, dye and electric contact, and synthesis method used to obtain these materials. In this chapter DSSCs components and different aspects related with photovoltaic principles and DSSCs performance will be studied. Special emphasis will put on to review physical, chemical and electrochemical principles of DSSCs operation.