Solar light absorption in organic photovoltaic devices based on P3HT:PCBM blend films

P3HT: PCBM blend films with different weight ratios were analyzed by calculating the number of photons absorbed under the standard AM 1.5 solar spectrum. Although the absorbed photons reduced, we found that the performance of PCBM:P3HT-based solar cells was not so affected by absorption spectra modifications as it was affected by the degradation mechanism of excitons dissociation and/or the transport properties of charge when increasing PCBM content. This analysis provide additional evidence for understanding the fact that the best power conversion efficiency can be reach using similar contents of P3HT and PCBM.