SCAPs

SCAPS, or Solar Cell Capacitance Simulator, is a software package used to model the electrical behavior of thin-film solar cells and related devices. It employs a one-dimensional drift-diffusion framework coupled with Poisson's equation and rate equations for generation, recombination, and trapping to simulate device performance under various operating conditions.

Users define a device by stacking layers that represent the active materials, contacts, and interfaces. Each layer is described by properties such as thickness, doping density, permittivity, and defect densities; traps and recombination pathways can be included at bulk and interface levels. The model supports common thin-film technologies (for example perovskite, organic, CIGS, and CdTe) and allows simulation of steady-state dark and irradiated I-V curves, as well as transient responses.

Outputs include current-voltage curves, spectral response or external quantum efficiency, capacitance-voltage and small-signal impedance, and depth-resolved distributions of carrier densities, electric fields, and recombination rates. The results help researchers analyze loss mechanisms, optimize layer properties, and interpret experimental data.

SCAPS is widely used in academic research and teaching to study device physics and to explore parameter dependencies. As a one-dimensional tool, it provides fast insights but has limitations in representing lateral inhomogeneities and full 3D effects. The accuracy of results depends on the quality of input parameters, and users typically compare simulations with experimental measurements to validate models. The software has evolved through community involvement and is distributed for research and educational use.