Honeycomb-shaped charge collecting electrodes for dipole-assisted back-contact perovskite solar cells

Dipole-field-assisted charge-transporting-material-free lead halide perovskite solar cells (PSCs) using a back-contact configuration feature intrinsic advantages, such as no parasitic light absorption and high architectural defect tolerance. Herein, a newly designed, highly defect tolerant honeycomb-shaped back-contact (HBC) electrode was incorporated into dipole-field-assisted-back-contact PSCs, aiming to optimize the charge transport distance before being collected by the electrodes. HBC-PSCs with three feature sizes were fabricated in order to understand the effect of charge transport distance on device performance. The photovoltaic performance of HBC-PSCs correlates inversely proportional to the feature sizes. The mechanism behind the performance difference is elucidated via a detailed analysis through device current voltage characterization, transient photovoltage decay measurement and photocurrent mapping. A comprehensive comparison between honeycomb-shaped and interdigitated finger back-contact electrodes for PSCs is also conducted.