Improvement in the hole collection of polymer solar cells by utilizing gold nanoparticle buffer layer

Insertion of gold nanoparticles (GNPs) layer between the indium tin oxide (ITO) and the photoactive polymer by simple spin-coating method is found to improve the photovoltaic effects of solar cells significantly. Cross sectional SEM image provides direct evidence that GNPs layer acts as a pure buffer layer in our devices. The improvement of the device performance is due to good transmission, high work function, good conductivity, and ultra-smooth surface roughness of GNPs layer. GNPs layer can act as a promising buffer layer to facilitate hole collection from polymer donor towards ITO anode.