Surface morphological and electrical characterization of thin film CdSe/P3HT composite layer for bulk hetero-junction solar cells

A blend of cadmium selenide quantum dots with conjugated polymer poly (3-hexylthiophene-2,5-diyl) (P3HT) was investigated as an active layer for the bulk hetero- junction solar cell. The surface morphology of composite active layer was controlled and investigated in relation to the bulk hetero-junction solar cell performance. Use of a binary solvent was intensively studied to improve the surface morphology. Smooth and uniform active layer surface could be obtained at optimum binary solvent composition with controlled drying process. The active layer sheet resistance was measured by using the transmission line method (TLM), and it was found that the percolation pathway for charge carrier transport could be developed above the threshold CdSe loading concentration