Efficient Method of Fabricating Polymeric Solar Cells in Multilayered Configuration Using Electrospray

Electrospray deposition (ESD) for the fabrication of multilayered (ML) bulk heterojunction polymeric solar cells via direct/inverted configurations was investigated. The active layer heterojunction (P3HT/PCBM) is deposited both in single and multilayered architectures. In ML configuration, the P3HT/PCBM blend film is sandwiched between thin donor (P3HT) and acceptor (PCBM) layers. In ZnO-based inverted solar cells, ZnO film synthesized by sol-gel process was deposited on ITO substrate using spin coatinng. Solar cells were fabricated via ESD and spin coating and the device's performance parameters were compared. Higher efficiency was obtained in the case of (ML) ESD device (direct structure). Post thermal treatment showed that ESD devices exhibit a power conversion efficiency (PCE) of 1.85% ML and 1.64% SL in direct structure while in the case of inverted structure PCEs of 1.30% ML and 0.82% SL were obtained as compared to 1.64% from the spin coated device at 120 degrees C. The ML ESD devices have shown an overall efficiency enhancement of 13% (direct) and 58% (inverted) over the single layer (SL) ESD devices. The enhanced performance in ML devices is because there is a spatially uninterrupted pathway to the charge carrier transport towards their respective electrodes.