Abstract
In recent years, the problem of non-renewable energy resource is becoming more serious. As a result, governments around the world at the moment pay much more attention to the development of alternative energy. Now, the organic solar cells is noted for mechanical flexibility, light weight, especially its simple and low-cost manufacturing. Those potential have made organic solar cells more promising in commercial applications. In this work, we report an inverted organic solar cells which required no electron selective layer were fabricated. The active layer was a bulk heterojunction (BHJ) consisting of blending of poly(3-hexylthiophene)(P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) in 1, 2-Dichlorobenzene. We found that ITO/P3HT：PCBM/PEDOT:PSS/Ag device improved the PCE from 0.89% to 4.06%(AM1.5G 100 mW/cm2). X-Ray photoelectron spectroscopy revealed further segregation in surface composition at the interface and the result were correlated to the current density-voltage measurement. We also extend this work to study a variety of materials as active and hole-transport layers in the inverted solar cells. The light soaked device were found the improvement irreversibly and excellent performance work in lifetime compared to conventional device. As a result, light soaking could be a cost-effective method to achieve efficient inverted organic solar cells.