Abstract
In recent years, polymer solar cells have become an important issue, because of attention to alternative energy resources. For polymer solar cells, the morphology of active layer and the series resistance both play important roles in designing highly efficient solar cells.Therefore, the influence of these two factors on efficiency of polymer solar cells based on poly(3-hexylthiophene) (P3HT) blended with [6,6]-pheneyl-C61 butyric acid methyl ester (PCBM) as the active layer is investigated in this thesis. In the first part of this thesis, we use thermal annealing and solvent annealing approach to change the active layer morphology. Under the optimal condition, the device efficiency of 3.75 % and 4 % are achieved for thermal annealing and solvent annealing. In the second part of this thesis, a water-soluble polyaniline, sulfonic acid ring substituted polyaniline (SPAN), which is synthesized in our laboratory, is adopted as a hole transport layer in the polymer solar cells.The device efficiency of 3.75 % is achieved which is similar to device with PEDOT：PSS as a hole transport layer (3.9 %), and indicates that SPAN has opportunity to substitute PEDOT：PSS as hole transport layer material in polymer solar cells. In the last part of this thesis, we use water-soluble crown-ether-substituted polyfluorene, poly[9,9’-bis(6’-(((1,4,7,10,13,16)hexaoxacyclooctadecanyl) methoxy)hexyl)fluorene] (PF-18-crown-6) as the electron transport layer for the first time to reduce series resistance in the polymer solar cells. The device efficiency can be promoted from 2.45 % to 2.82 % after insertion of this layer, which indicates PF-18-crown-6 can reduce series resistance of polymer solar cells and enhance the device efficiency.