Role of cation-mediated recombination in perovskite solar cells

Ajay Singh, Waldemar Kaiser, Alessio Gagliardi

Research output: Contribution to journalArticlepeer-review

21 Scopus citations

Abstract

The origin of the hysteresis in the current–voltage (J–V) characteristics in perovskite solar cells (PSCs) is one of the most debated topics of recent years. Hysteretic effects are connected with the slow redistribution of ionic defects during the voltage sweep. Existing literature focuses on the potential screening due to accumulated ions, solely, while neglecting the possibility of charge trapping and subsequent recombination via ions. We investigate the role of cation-mediated recombination of ions using time-dependent drift–diffusion simulations in MAPbI3 PSCs. Slow-moving cations are considered as traps for the electrons. Trapped electrons can subsequently recombine non-radiatively with holes. We analyze the role of the cation-mediated trapping and its parameters (capture coefficient, cation energy, ion mobility) as well as the scan rate on the device performance. For shallow cation energies, a decrease in open-circuit voltage and slight enhancement in hysteresis is observed. Deep cation energies lead to a substantial deterioration of device performance and large hysteresis enhancement. The presented study emphasizes the importance of considering the interaction of ions with charge carriers beyond the simple electrostatic models to improve our understanding of PSCs.

Original languageEnglish
Article number110912
JournalSolar Energy Materials and Solar Cells
Volume221
DOIs
StatePublished - Mar 2021

Keywords

  • Cation-mediated recombination
  • Drift–diffusion model
  • Ionic defects
  • J–V hysteresis
  • Perovskite solar cell

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