Improved stability of organic photovoltaic cells using poly(ethylene oxide) as cathode interfacial layer

Polymer bulk-heterojunction solar cells with poly(ethylene oxide)(PEO) as cathode interfacial layer,and P3HT:PCBM as active layer are prepared.The effect of the PEO layer′s thickness on the performance of polymer solar cells and the degradation characteristics of this system are investigated.The stabilities of the device with PEO interfacial layer and the control device are copared.The differences of the resistances between the device with PEO interfacial layer and the control device are studied.The results indicate that the performance of polymer solar cells enhanced evidently,but the series resistance of the decice reduced obviously.The power conversion efficiency(PCE) of the device with PEO interfacial layer is 3.36%,and then decreases to 20% of the initial value after 90 h.Compared with the control device(PCE is 1.92%,decreased to 5% of the initial value after 90 h),the power conversion efficiency of the device with PEO interfacial layer increased by 75% and the stability extended 3 times.