Effect of Molybdenum Oxide Anode Buffer Layer on the Performance of Inverted Small Molecular Organic Solar Cells

Small molecular organic solar cells (OSCs) with an inverted structure of indium tin oxide (ITO)/cesium carbonate (Cs2CO3)/C60/subphthalocya- nine(SubPc)/molybdenum oxide (MoO3)/Ag were fabri- cated and studied. By using the equivalent circuit model and transfer matrix theory, the influence of the thickness of MoO3 on the electrical and optical characteristics of the device was systematically investigated. The results indicate that at the optimized thickness of 15 nm, the power conversion efficiency was increased to 0.57% under AM 1.5 solar illumination at an intensity of 100 mW/cm2. The enhancement of the device performance was attributed to the optical spacer effect and the good protection of active layer from Ag diffusion and charge extraction without introducing more series resistance. Finally, the lifetime measure- ment showed that the stability of OSCs was remarkably enhanced by introducing inverted structure.