  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.
