[Paper Review] Ionic-to-electronic current amplification in hybrid perovskite solar cells

Davide Moia, Ilario Gelmetti+10 more|arXiv (Cornell University)|May 16, 2018

Perovskite Materials and Applications3 citations

TL;DR

This paper proposes a transistor-like model where ionic charge redistribution at perovskite contacts modulates electronic injection and recombination barriers, leading to an amplification of electronic current relative to ionic current. The authors develop a validated equivalent circuit model using time-dependent drift-diffusion simulations, enabling general interpretation of perovskite solar cell behavior and suggesting design strategies for tunable capacitor- and inductor-like thin-film components.

ABSTRACT

Mobile ions in hybrid perovskite semiconductors introduce a new degree of freedom to electronic devices suggesting applications beyond photovoltaics. An intuitive device model describing the interplay between ionic and electronic charge transfer is needed to unlock the full potential of the technology. We describe the perovskite-contact interfaces as transistors which couple ionic charge redistribution to energetic barriers controlling electronic injection and recombination. This reveals an amplification factor between the out of phase electronic current and the ionic current. The resulting simple equivalent circuit model, which we verified with time-dependent drift-diffusion simulations of impedance spectra, allows a general description and interpretation of perovskite solar cell behaviour. Our findings also suggest a strategy to design thin film electronic components with large, tuneable, capacitor-like and inductor-like characteristics.

Motivation & Objective

• To develop a fundamental understanding of the interplay between ionic and electronic charge transfer in hybrid perovskite semiconductors.
• To address the lack of a unified device model explaining how mobile ions influence electronic behavior in perovskite solar cells.
• To establish a generalizable equivalent circuit model that captures the dynamic behavior of perovskite devices.
• To enable design principles for thin-film electronic components with tunable capacitor- and inductor-like characteristics.

Proposed method

• Modeling perovskite-contact interfaces as transistors that couple ionic charge redistribution to energetic barriers for electronic injection and recombination.
• Introducing an amplification factor linking the out-of-phase electronic current to the ionic current, quantifying the coupling strength.
• Developing an equivalent circuit model based on the ionic-electronic coupling mechanism for general device description.
• Validating the model using time-dependent drift-diffusion simulations of impedance spectra across varying ionic and electronic conditions.
• Analyzing the frequency-dependent response to extract dynamic behavior and confirm consistency with experimental impedance trends.
• Using the model to predict and explain the emergence of capacitor-like and inductor-like characteristics in thin-film systems.

Experimental results

Research questions

• RQ1 How does ionic charge redistribution at perovskite interfaces influence electronic current injection and recombination dynamics?
• RQ2 What is the quantitative relationship between ionic current and the resulting electronic current in perovskite solar cells?
• RQ3 Can a simple equivalent circuit model accurately describe the complex ionic-electronic coupling observed in perovskite devices?
• RQ4 What design principles emerge for creating tunable electronic components with capacitor- and inductor-like behavior from perovskite thin films?

Key findings

• The ionic-to-electronic current amplification factor emerges as a key parameter linking ionic motion to electronic response in perovskite heterostructures.
• The proposed equivalent circuit model successfully reproduces impedance spectra from time-dependent drift-diffusion simulations, validating its physical consistency.
• The model reveals that ionic redistribution dynamically modulates interfacial energy barriers, thereby controlling electronic injection and recombination.
• The system exhibits capacitor-like and inductor-like characteristics that are tunable via ionic dynamics and interfacial engineering.
• The amplification mechanism enables a general framework for interpreting non-ideal behavior in perovskite solar cells, such as hysteresis and frequency dispersion.
• The findings open pathways for designing functional thin-film electronic components based on hybrid perovskites with tailored dynamic responses.