Low-Frequency Carrier Kinetics in Perovskite Solar Cells

Vinod K. Sangwan, Menghua Zhu, Sarah Clark, Kyle A. Luck, Tobin J. Marks, Mercouri G. Kanatzidis, Mark C. Hersam*

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Hybrid organic-inorganic halide perovskite solar cells have emerged as leading candidates for third-generation photovoltaic technology. Despite the rapid improvement in power conversion efficiency (PCE) for perovskite solar cells in recent years, the low-frequency carrier kinetics that underlie practical roadblocks such as hysteresis and degradation remain relatively poorly understood. In an effort to bridge this knowledge gap, we perform here correlated low-frequency noise (LFN) and impedance spectroscopy (IS) characterization that elucidates carrier kinetics in operating perovskite solar cells. Specifically, we focus on planar cell geometries with a SnO 2 electron transport layer and two different hole transport layers - namely, poly(triarylamine) (PTAA) and spiro-OMeTAD. PTAA and spiro-OMeTAD cells with moderate PCEs of 5-12% possess a Lorentzian feature at ∼200 Hz in LFN measurements that corresponds to a crossover from electrode to dielectric polarization. In comparison, spiro-OMeTAD cells with high PCEs (>15%) show 4 orders of magnitude lower LFN amplitude and are accompanied by a cyclostationary process. Through a systematic study of more than a dozen solar cells, we establish a correlation with noise amplitude, PCE, and fill factor. Overall, this work establishes correlated LFN and IS as an effective methodology for quantifying low-frequency carrier kinetics in perovskite solar cells, thereby providing new physical insights that can rationally guide ongoing efforts to improve device performance, reproducibility, and stability.

Original languageEnglish (US)
Pages (from-to)14166-14174
Number of pages9
JournalACS Applied Materials and Interfaces
Volume11
Issue number15
DOIs
StatePublished - Apr 17 2019

Keywords

  • 1/ f noise
  • degradation
  • hybrid perovskite solar cells
  • impedance spectroscopy
  • methylammonium lead iodide
  • mobile ions

ASJC Scopus subject areas

  • Materials Science(all)

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