Effect of Polarization on Performance of Inverted Solar Cells Based on Molecular Ferroelectric 1,6-Hexanediamine Pentaiodide Bismuth with PCBM as Electron Transport Layer

The depolarization field of ferroelectric photovoltaic materials can enhance the separation and transport of photogenerated carriers, which will improve the performance of photovoltaic devices, thus attracting the attention of researchers. In this paper, a narrow bandgap molecular ferroelectric Hexane-1,6-diammonium pentaiodobismuth (HDA-BiI5) was selected as the photo absorption layer for the fabrication of solar cells. After optimizing the ferroelectric thin film by the antisolvent process, the effect of different polarization voltages on the performance of ferroelectric devices was studied. The results showed that there was a significant increase in short-circuit current density, and the photoelectric conversion efficiency showed an overall increasing trend. Finally, we analyzed the internal mechanism of the effect of polarization on the device.