(360d) The New Fabrication Method of the Active Layer of Solar Cells by Langmuir-Blodgett Technique

The morphology of the active layer in the organic-inorganic solar cell is a crucial factor to the power conversion efficiency (PCE). We demonstrate how the Langmuir-Blodgett (LB) technique can be used as a platform to construct the active layer made of CdSe tetrapods (TPs) and poly-3(hexylthiophene) (P3HT). With the assistant of a lipid molecule, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), as a soft template, we are able to control the assembly of CdSe TPs by altering the nanoparticle aggregation from connected nanodiscs to nanowire networks by tuning the surface pressure at the air/water interface. Consecutively transferring the network structure onto the pretreated substrate allows us to go from the two-dimensional thin film to the three-dimensional multi-layer configuration, where we spin-coat a conductive polymer, poly(3-hexylthiophene) (P3HT), onto the substrate to make the desired active layer. The transmission electron microscopy (TEM) images reveal that the network structures build vertically without collapse. This novel fabrication we propose here shows the ability of improving the performance of the solar cell by manipulating the morphology of the active layer with the help of the LB technique.