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Role of Monovalent Cations in the Dielectric Relaxation Processes in Hybrid Metal Halide Perovskite Solar cells
Journal
ACS Applied Energy Materials
Date Issued
2022-03-28
Author(s)
Hossain, Kashimul
Singh, Shivam
Kabra, Dinesh
Abstract
Perovskite solar cells (PSCs) are the fastest-growing photovoltaic devices in the solar cells community and offer a bright future for economic solar electricity. In the last few years, it has been observed that the efficiency and stability of the PSCs can be enhanced by introducing multiple cations into the perovskite crystal structure. Herein, we compared triple monovalent cation-based PSCs (FA0.83MA0.17)0.95Cs0.05Pb(I0.90Br0.10)3 (CsFAMA) with single monovalent cation-based PSC MAPbI3 (MAPI) through frequency-dependent photocurrent and dielectric measurements in terms of the dielectric relaxation process. The dielectric relaxation time constant (τd) was lower for the CsFAMA-based PSC compared to the MAPI-based PSC. The lower τd is attributed to a lower dielectric constant based on classical semiconductor physics. Unprecedentedly, the relaxation process is correlated with the presence of monovalent cations of CsFAMA vs MAPI as an absorber in PSCs, which is well correlated with the presence of relative defect density. We note that defect formation under illumination conditions reduces JSC as a major component in PV parameters, which is significant in MAPI PSCs. This can be hypothesized based on relative ion density accumulation at the interface of charge extracting contact as per available literature. This study provides unique in-depth knowledge of the role of monovalent cations in the dielectric relaxation process and their relation with the defects and thermal stability of halide perovskite semiconductor-based solar cells.
Volume
5
Subjects