Making highly efficient multi-junction polymer solar cell or hybrid solar cell is very attractive. Due to the narrow absorption band of polymeric semiconductors, broad light harvesting covering the whole range of the solar irradiation spectrum cannot be achieved in a single-junction device, multi-junction polymer solar cells composed of complementary absorbed photoactive layers helps to harvest more light, in turns improve the power conversion efficiency. 

polymer solar cells Multi-junction Transparent Superhydrophobic Coating Nanostructured Materials​