Carbon nanotube incorporation: A new route to improve the performance of organic–inorganic heterojunction solar cells

Incorporation of oxidized camphoric multi-walled carbon nanotubes (MWCNs) in the polymer layer of regioregular poly(3-octylthiophene)/n-Si heterojunction solar cell is observed to improve the performance of the device by many folds. We report power conversion efficiency, open circuit voltage, short-circuit current density, and fill factor of 0.175%, 0.22 V, 2.915 mA/cm2, 0.27 respectively, for an un-optimized cell containing MWCNs. Reference cells without MWCNs show much lower performance. Improved device performance is due to better hole transport, easy exciton splitting and suppression of charge carrier recombination as a result of incorporation of MWCNs. MWCNs, being low cost materials, seem to be promising materials for improving device performance of organic–inorganic heterojunction solar cells.