Synthesizing the composite of P3HT/Gr as the active layer for polymer solar cells

The active layer of the polymer solar cells is one of the most important parts of solar cells, because it has the duty of exciton production. Bulk heterojunction architecture is the most dominate strategy to design the active layer. Among different materials used as donor, P3HT is the most accepted one. In this regard we synthesized P3HT with Grignard method. We confirmed the P3HT structure by HNMR and FT-IR. We also added functional groups (-OH) to the P3HT structure. For the acceptor of the active layer, we synthesized graphene oxide (GO) with three methods (Hummers, improved hummers and modified Hummers method) [1]. The best graphene oxide was prepared by improved Hummers method which was confirmed by Raman, XRD and SEM. The composite of the P3HT and GO was prepared, and the hydroxyl, carboxylic acid and epoxy groups of GO interacted with hydroxyl group of P3HT. The binding of these two materials, can improve the efficiency of solar cells by modulating the work function. Due to the structural deficiency and the distortion of basal plane of GO, the conductivity is low. In this regard we reduced GO by hydrazine hydrate, so the conductivity increased due to the formation of graphene (Gr).