Tailoring Spatial Distribution of the Optical Field Intensity in Semitransparent Inverted Organic Solar Cells

A WO 3 /Ag/WO 3 multilayer structure was introduced as a transparent top anode in semitransparent inverted organic solar cells. The inner WO 3 film served as a hole extraction layer, while the outer WO 3 film acted as a light coupling layer to enhance optical transmittance of the devices. The dependence of device performances on the thickness of the outer WO 3 capping layer was investigated. Experimental results showed that both optical and electrical properties of the devices with WO 3 /Ag/WO 3 as a transparent top anode could be tailored by varying the thickness of the outer WO 3 capping layer. The spatial distribution of the optical field and the exciton generation rate across the active layer were calculated to discuss the effect of the thickness of the outer WO 3 capping layer on the photocurrent.