Effect of buffer layers on the performance of P3HT: PCBM solar cells

We have studied the effect of buffer layers on the performance of poly(3-hexylthiophene-2,5-diy1) (P3HT): C61-butyric acid methyl ester (PCBM) bulk heterojunction solar cells. We proved that depositing a thin pentacene layer between metal cathode and P3HT: PCBM blend and introducing a thin P3HT layer between ITO and photoactive layer, would improve the power conversion efficiency of polymer bulk heterojunction solar cells when compared with the cells without the buffer layers. In the study, the buffer layers increased short circuit density (Jsc) and open circuit voltage (Voc) under the illumination by white light from a solar simulator with an incident intensity of 100mW/cm2. The thin pentacene layer as a cathode buffer layer modifying the contact between the active layer and the cathode, the thin layer of P3HT as a anode buffer layer enhancing the electron blocking ability were responsible for the improvement on the performance of photovoltaic device.