Optimization of Active Layer Thickness for High Performance Organic Tandem Solar Cells by Combining the Optical and the Charge Transport Models

摘要

The realization of stacked tandem solar cells based on materials having different absorption properties provides a route to achieve high power conversion efficiency of organic solar cells . When two sub-cells are stacked in a tandem architecture, the light which has not been absorbed in the front sub-cell can further be absorbed in the back sub- cell. When the two sub-cells are connected in series, it is expected that the open-circuit voltage of tandem cell equals to the sum of the open- circuit voltages of the individual cells, whereas the short-circuit current density of tandem cell is rather complicated to predict from the short- circuit current densities of each sub-cells because it depends largely upon the thickness of active layers. Consequently, in order to fully exploit the opportunity offered by this tandem approach, the thicknesses of the front and the back cells should be carefully optimized.