Charge Accumulation and Hysteresis in Perovskite-Based Solar Cells: An Electro-Optical Analysis

Bo Wu, Kunwu Fu, Natalia Yantara, Guichuan Xing, Shuangyong Sun, Tze Chien Sum*, Nripan Mathews

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

238 Citations (Scopus)

Abstract

Organic-inorganic hybrid perovskite solar cells based on CH3NH3PbI3 have achieved great success with efficiencies exceeding 20%. However, there are increasing concerns over some reported efficiencies as the cells are susceptible to current-voltage (I-V) hysteresis effects. It is therefore essential that the origins and mechanisms of the I-V hysteresis can clearly be understood to minimize or eradicate these hysteresis effects completely for reliable quantification. Here, a detailed electro-optical study is presented that indicates the hysteresis originates from lingering processes persisting from sub-second to tens of seconds. Photocurrent transients, photoluminescence, electroluminescence, quasi-steady state photoinduced absorption processes, and X-ray diffraction in the perovskite solar cell configuration have been monitored. The slow processes originate from the structural response of the CH3NH3PbI3 upon E-field application and/or charge accumulation, possibly involving methylammonium ions rotation/displacement and lattice distortion. The charge accumulation can arise from inefficient charge transfer at the perovskite interfaces, where it plays a pivotal role in the hysteresis. These findings underpin the significance of efficient charge transfer in reducing the hysteresis effects. Further improvements of CH3NH3PbI3-based perovskite solar cells are possible through careful surface engineering of existing TiO2 or through a judicious choice of alternative interfacial layers.

Original languageEnglish
Article number1500829
JournalAdvanced Energy Materials
Volume5
Issue number19
DOIs
Publication statusPublished - Oct 7 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ASJC Scopus Subject Areas

  • Renewable Energy, Sustainability and the Environment
  • General Materials Science

Keywords

  • charge accumulation
  • hysteresis
  • perovskite solar cells
  • slow dynamics

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