Optimizing P3HT/PCBM/MWCNT films for increased stability in polymer bulk heterojunction solar cells

The effect of multi-walled carbon nanotubes on the properties of P3HT:PCBM based solar cells has been studied. The concentration of MWCNT was optimized at 0.2% and the concentration of P3HT:PCBM was increased from 20 mg/ml to 30 mg/ml to obtain highest efficiency. An increase in charge carrier mobility was also observed, which is attributed to high charge transport properties of MWCNT. The active layer was optically stable with respect to absorption, whereas the emission spectra revealed an increase in charge recombination with time. The solar cells doped with MWCNT exhibited increased stability as compared to undoped cells. (C) 2014 Elsevier B.V. All rights reserved.