Solar Energy Materials and Solar Cells, Vol.157, 337-345, 2016
Characterization and modeling of organic (P3HT:PCBM) solar cells as a function of bias and illumination
We investigated the response of roll coated organic solar cells at different bias voltages and illumination levels to implement a detailed impedance model. The technique used for the investigation is based on the combination of standard DC characterization with the impedance spectroscopy at different bias and illumination intensity conditions. We analyzed both fresh and intentionally degraded cells. The impedance spectra show different peaks evolutions, depending on the degradation of the cells. Moreover, the same trend appears by measuring the cell at different illumination levels. To describe the cell impedance behaviors we suggest an electrical model based on distributed elements. By fitting the model to experimental data, we extrapolate the parameters related to electron transport, recombination and accumulation. The main differences between fresh and degraded samples are underlined. (C) 2016 Elsevier B.V. All rights reserved.
Keywords:Organic photovoltaic heterojunction solar cell;Impedance spectroscopy;AC model;UV degradation;Electrical model;Diffusion and recombination