**2. Driving forces to develop organic PV cells**

Energy is the greatest technological problem of the 21st century. Energy conversion efficiency is a dominant factor to meet the increasing demand of energy worldwide. Solar energy looks easy alternative next to conventional sources, like electricity, coal and fuels. The use of solar energy can become more popular by developing photovoltaic (PV) cells of improved efficiency. The crystalline silicon PV cells are 12 % efficient with very high manufacturing cost. Thin-film cells based on CdTe, CuInS2 and amorphous Si are promising, but In is expensive, Cd is toxic and amorphous Si isn't stable. A 10 % efficient cell can generate energy level equivalent to 100 W/m2. Recently, the development of photovoltaic fibre, a great innovation in the field of photovoltaics made the technology more attractive and smart7-12.
