Perovskite Solar Cells (PSC) have attracted great attention due to the high efficiencies achieved in the past few years (up to 24.2 %). Perovskite semiconductors show excellent light absorption and large charge-carrier mobilities. In addition, device fabrication is low cost and easily up-scalable. However, the current density-voltage curve (J-V) shows hysteresis and devices suffer from stability issues which are still poorly understood. Among all perovskite materials, mixed-cation lead mixed-halide PSC have become very popular due to their high efficiencies and reasonably good stabilities^1,2. On the other hand, Impedance Spectroscopy (IS) is a very valuable non-destructive technique to obtain information about dynamical mechanisms occurring both in the bulk and at the interfaces³ . In this work, J-V curves and the impedance response have been measured for CsFAPbIBr-based PSC from 1 Hz up to 1 MHz, under different illumination levels (from 0.06 mW/cm² to 100 mW/cm² ) both at 0 V (short circuit) and at V_oc (open circuit). Impedance spectra show two significant arcs, associated to different recombination and charge accumulation mechanisms. IS data have been fitted to a circuital model that consists of a low-frequency RCPE subcircuit in series with a high frequency resistance, all shunted with a high-frequency capacitance. Dependence of the circuital parameters with V_oc and I_sc will be discussed.

Date Published: 10 October 2019
PDF: 7 pages
Proc. SPIE 11094, Organic, Hybrid, and Perovskite Photovoltaics XX, 110940J (10 October 2019); doi: 10.1117/12.2528697

Published in SPIE Proceedings Vol. 11094:
Organic, Hybrid, and Perovskite Photovoltaics XX
Zakya H. Kafafi; Paul A. Lane; Kwanghee Lee, Editor(s)