Effects of Annealing on Bulk-heterojunction Organic Solar Cells

摘要

This work investigates the effects of annealing on bulk-heterojunction organic solar cells based on a thin film blend of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61butyricacidmethylester (PCBM). This report focuses on changes in the physical properties of the P3HT:PCBM film, as well as the electronic performance of organic photovoltaic (OPV) devices annealed in the range of temperatures from 80 to 180 ℃, in a nitrogen atmosphere. These were investigated using uv-vis absorbance spectra, X-ray diffraction (XRD) and external quantum efficiency (EQE) measurements. The results of this report show that the optimal thermal annealing temperature is 130 ℃. Analysis of film and electrical characteristics, as a function of thermal annealing parameters, indicates that a trade-off is established. It is shown that optimising annealing conditions requires careful consideration of the interplay between charge carrier conduction and excitonic dissociation.