Probing the ionic defect landscape in halide perovskite solar cells

Abstract

Point defects in metal halide perovskites play a critical role in determining their properties and optoelectronic performance; however, many open questions remain unanswered. In this work, we apply impedance spectroscopy and deep-level transient spectroscopy to characterize the ionic defect landscape in methylammonium lead triiodide ($MAPb{I}_3$) perovskites in which defects were purposely introduced by fractionally changing the precursor stoichiometry. Our results highlight the profound influence of defects on the electronic landscape, exemplified by their impact on the device built-in potential, and consequently, the open-circuit voltage. Even low ion densities can have an impact on the electronic landscape when both cations and anions are considered as mobile. Moreover, we find that all measured ionic defects fulfil the Meyer--Neldel rule with a characteristic energy connected to the underlying ion hopping process. These findings support a general categorization of defects in halide perovskite compounds.

References in corpus (10)

• Direct Measurement of the Exciton Binding Energy and Effective Masses for Charge carriers in an Organic-Inorganic Tri-halide Perovskite
• Evidence for ion migration in hybrid perovskite solar cells with minimal hysteresis
• Quantification of Ion Migration in CH3NH3PbI3 Perovskite Solar Cells by Transient Capacitance Measurements
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• Shining Light on Photoluminescence Properties of Metal Halide Perovskites
• Impact of Small Phonon Energies on the Charge-Carrier Lifetimes in Metal-Halide Perovskites
• Insights from Device Modeling of Perovskite Solar Cells
• Effect of Precursor Stoichiometry on the Performance and Stability of MAPbBr3 Photovoltaic Devices

Cited by in corpus (4)

• Are Shockley-Read-Hall and ABC models valid for lead halide perovskites?
• Defect tolerant device geometries
• Tracing Ion Migration in Halide Perovskites with Machine Learned Force Fields
• Unraveling the defect landscape of wide-bandgap perovskites from electrical and photoelectrical characterization of thin films and solar cells