Pentacene nanostructural interlayer for the efficiency improvement of polymer solar cells

In poly(3-hexylthiophene) mixed with phenyl C61-butyric acid methyl ester heterojunction polymer solar cells, organic small molecular pentacene was introduced as the interfacial layer between PEDOT:PSS coated ITO substrates and polymer layer. It is found that the short circuit current density and power conversion efficiency were distinctly improved due to the introduction of the nanostructural pentacene interlayer. The nearly 100% power conversion efficiency improvement was obtained on the cells with a 4 nm pentacene interlayer, which benefits from the increased short circuit current from 2.34 mA/cm2 to 5.76 mA/cm2. The morphology of different thicknesses of pentacene thin films was observed by atomic force microscopy. The effect of pentacene interlayer's thickness on the distribution of light in the active layer was simulated by using a transfer matrix mode.