Effect of hybrid carbon nanotubes–bimetallic composite particles on the performance of polymer solar cells

Hybrid carbon nanotubes–bimetallic composite nanoparticles with sea urchin-like structures (SU-CNTs) were introduced to bulk heterojuction polymer-fullerene solar cells to improve their performance. The SU-CNTs were composed of multi-walled CNTs, which were grown radially over the entire surface of the bimetallic nanoparticles composed of Ni and Al. SU-CNTs with a precisely controlled length of ∼200±40 nm were dispersed homogenously in a polymer active layer. Compared with a pristine device (i.e., without SU-CNTs), the SU-CNTs-doped organic photovoltaic (OPV) cells showed an improved short-circuit current density and power conversion efficiency from 7.5 to 9.5 mA/cm2 and 2.1±0.1% to 2.2±0.2% (max. 2.5%), respectively. The specially designed SU-CNTs have strong potential as an effective exciton dissociation medium in the polymer active layer to enhance the performance of organic solar cells.