We show that an advanced cathode buffer design, consisting of bathocuproine/3,4,9,10-perylenetetracarboxylic bis-benzimidazole/Ag, increases the short-circuit current of organic planar heterojunction cells and reduces the J-V slope at reverse voltages. We study the physical origin of these effects by measuring reflectivity, voltage dependent external quantum efficiency, and voltage dependent photoluminescence. Our findings suggest that the observed effects are mainly associated with a voltage dependent polaron-induced exciton quenching in the C60 layer. Finally, this improved cathode buffer design is applied to a diindeno[1,2,3-cd:1′,2′,3′-lm]perylene/ C70 based cell, leading to a considerable planar heterojunction efficiency of 5.7%.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)