Performance improvement in poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester polymer solar cell by doping wide-gap material tris(phenylpyrazole)iridium

This letter demonstrates the high external quantum efficiency (EQE) of poly(3-hexylthiophene) (P3HT)-based polymer solar cells and their enhanced hole transport ability through doping a wide-band-gap material tris(phenylpyrazole) iridium [Ir(ppz)3]. Doping Ir(ppz)3 can enhance low wavelength optical absorption capacity and doping a small amount of Ir(ppz)3 can also improve the crystallinity of P3HT. Moreover, the large energy barrier between Ir(ppz)3 and the polymer active layer, which can reduce the electron current densities and increase the hole current densities, indicates a more balanced carrier transport based on hole- and electron-only devices. Such characteristics contribute to efforts to improve the photocurrent density of polymer solar cells.