Along with two major problems of the energy shortage and environmental pollution

people get further in the development and utilization of the solar energy. In the usage of the solar energy

solar cells are considered to be the most promising way. Meanwhile

the application of inorganic solar cells is limited because of the fatal weakness. Polymer solar cells (PSCs) have continuously drawn great interest in the photovoltaic field due to their several advantages

such as low cost

light weight

and easy combination and modification. In recent years

the power-conversion efficiencies of PSCs had already been more than 8%. In this article

how to design efficient PSCs was reviewed. Relations between materials and open-circuit voltage

short-circuit current density and fill factor of PSCs were discussed. At last

prospect of PSCs was expected.