Characterization of P3HT:PCBM:CdSe Hybrid Solar Cells

We have investigated the effect of adding CdSe quantum dots (QDs) with their hexadecylamine (HDA) ligands coating in ITO/SPT/P3HT:PCBM/Al bulk heterojunction (BHJ) organic photovoltaic cells (OPV). At first, we found that the optimal thermal treatment was a post cathode deposition annealing, due to an effective surface area 10.8% larger compared to a pre-cathode thermal treatment. Absorbance spectra for hybrid cells with incorporated QDs diameters ranging from 2.2 nm to 6.3 nm show the largest absorbance for 3.3 nm QD diameter. The 3.3 nm QD also gives the lowest power performance. We explained the general degraded performance as an effect of the HDA ligands coating around QDs. Finally, in order to track the lateral inhomogeneity of the final device, we have mapped the I-V over the entire surface cell (2 cm x 2 cm) with a definition of 200 pts x 200 pts.