[Paper Review] Driftfusion: An open source code for simulating ordered semiconductor devices with mixed ionic-electronic conducting materials in one-dimension

Philip Calado, Ilario Gelmetti+4 more|arXiv (Cornell University)|Sep 9, 2020

Perovskite Materials and Applications4 citations

TL;DR

Driftfusion is an open-source MATLAB-based simulation tool for one-dimensional semiconductor devices with mixed ionic-electronic conducting materials, enabling modeling of up to four charge carriers (electrons, holes, and two ionic species) via fully coupled time-dependent continuity equations and Poisson’s equation. Its key innovation is a discrete interlayer interface approach that allows flexible, interface-specific property assignment without relying on abrupt boundary conditions, enabling accurate simulation of perovskite-based optoelectronic devices with hysteresis and transient response.

ABSTRACT

The recent emergence of lead-halide perovskites as active layer materials for thin film semiconductor devices including solar cells, light emitting diodes, and memristors has motivated the development of several new drift-diffusion models that include the effects of both mobile electronic and ionic charge carriers. The aim of this work is to provide a comprehensive guide to Driftfusion, a versatile simulation tool built for simulating one-dimensional ordered semiconductor devices with mixed ionic-electronic conducting layers. Driftfusion enables users to model devices with multiple, distinct, material layers and up to four charge carrier species: electrons and holes by default plus up to two ionic species. The time-dependent carrier continuity equations are fully-coupled to Poisson's equation enabling transient optoelectronic device measurement protocols to be simulated. In addition to material and device-wide properties, users have direct access to adapt the physical models for carrier transport, generation and recombination. Furthermore, a graded-interface approach circumvents the requirement for boundary conditions at material interfaces and enables interface-specific properties, such as high rates of interfacial recombination, to be introduced.

Motivation & Objective

• To address the lack of accessible, flexible simulation tools for one-dimensional semiconductor devices incorporating both electronic and mobile ionic charge carriers.
• To overcome limitations in existing simulators that require complex numerical knowledge to modify physical models or device architectures.
• To enable accurate modeling of interfacial recombination and ionic charge dynamics in perovskite-based devices, particularly those showing current-voltage hysteresis.
• To provide a user-friendly, open-source platform that supports customizable material layers, carrier transport models, and transient measurement protocols.
• To verify the tool’s accuracy against analytical and numerical benchmarks, ensuring reliable simulation of real-world device behavior.

Proposed method

• The tool uses a drift-diffusion framework based on the van Roosbroeck system, coupling time-dependent continuity equations for each charge carrier species with Poisson’s equation to model electrostatics.
• It supports up to four charge carrier species: electrons, holes, and two distinct ionic species, enabling simulation of complex mixed ionic-electronic conductors.
• A discrete interlayer interface approach replaces traditional boundary conditions by modeling material properties as graded across thin interfacial layers, allowing interface-specific parameters to be defined.
• The interface model uses analytical approximations for carrier densities and fluxes within interfacial regions, enabling volumetric recombination schemes to simulate surface recombination effects.
• The simulation is implemented using MATLAB’s pdepe toolbox, with built-in functions for defining device architecture, applying time-dependent voltage and light protocols, and analyzing outputs.
• Users can modify physical models (e.g., mobility, generation, recombination) directly, and the code supports parallel computation for multiple simulations.

Experimental results

Research questions

• RQ1 Can a flexible, open-source simulation tool accurately model transient optoelectronic responses in one-dimensional semiconductor devices with mixed ionic-electronic conductors?
• RQ2 How does the discrete interlayer interface approach compare to traditional abrupt interface models in terms of accuracy and numerical stability?
• RQ3 To what extent can Driftfusion reproduce experimentally observed hysteresis effects in perovskite solar cells and memristors?
• RQ4 Can the tool support customizable physical models and multi-layer device architectures without requiring deep expertise in numerical methods?
• RQ5 How well does Driftfusion agree with analytical solutions and existing numerical models across diverse device configurations?

Key findings

• Driftfusion successfully reproduces general device behavior across multiple test cases, showing good agreement with both analytical solutions and existing numerical models.
• The discrete interface approach produces results comparable to those from simulators using abrupt interfaces, with only marginal errors due to linear discretization and interface treatment.
• The tool accurately captures current-voltage hysteresis in perovskite devices by including mobile ionic species and interface-specific recombination centers.
• The simulation framework allows users to easily modify physical models and introduce new material layers, significantly reducing the barrier to customization compared to existing tools.
• Verification against two analytical models and two existing numerical models confirmed the reliability and robustness of Driftfusion’s numerical implementation.
• The code is freely available on GitHub and supports advanced features such as parallel solution calculation and built-in analysis and plotting functions for output visualization.