Effects of the negative electrode contact on the performance of poly(hexylthiophene):6,6-phenyl-C-61-butyric acid methyl ester based organic solar cells

In this paper, we report the results on electrical characterization of solar cells using blends of poly(hexylthiophene) (P3HT) and 6,6-phenyl-C-61-butyric acid methyl ester (PCBM) as active energy conversion materials and different negative electrode contacts. The electrical properties analyzed by the current-voltage-temperature (I-V-T) measurements and the charge based deep level transient spectroscopy show that the low efficiency of the devices using Al electrode as compared to CaAl one is due to a reduction of defect density in the interfacial contact region and fast, irreversible degradation of the Al/(P3HT:PCBM) contact. (C) 2014 AIP Publishing LLC.