Enhance carrier transport and efficiency by twice-growth ZnO nanorods in inverted polymer solar cells

For polymer solar cells, the efficiency loss is caused by considerable carrier recombination in active layer based on low carrier diffusion length or low carrier collection. Here, to increase the carrier collection, ZnO nanorods are inserted between thin ZnO seed layer and active layer. Consequently, the carrier transport is improved by using ZnO nanorods, and then the carrier collection rate and the efficiency are enhanced.