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

• MWCNT doped P3HT:PCBM based solar cells are optimized for increased efficiency.
• Degradation studies showed that MWCNT stabilizes the cell performance.
• Mobility and basic device characteristics decreased with time.
• Photoluminescence studies with time showed an increase in charge recombination.
• Degradation for devices kept in air is faster as compared to the samples in vacuum.

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 20mg/ml to 30mg/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.