SAIP2026

Effect of the absorber layer thickness and defect density on the performance of KGeCl3 perovskite solar cells

8 Jul 2026, 11:00

20m

Lecture Hall GH1 (University of the Western Cape)

Oral Presentation Track A - Physics of Condensed Matter and Materials Physics of Condensed Matter and Materials

Speaker

Ms Bridgette Kabekwa (Department of Physics, University of Limpopo, Private bag X 1106, Sovenga, 0727, Polokwane, South Africa)

Description

Bridgette Kabekwa1, Mulatedzi Gandamipfa1, Petros Ntoahae1, Eli Danladi2,3 and Rapela Maphanga4,5

1Department of Physics, University of Limpopo, Private bag X 1106, Sovenga, 0727, Polokwane, South Africa
2Department of Mathematical and Physical Sciences, Central University of Technology, Free State, South Africa
3 Department of Physics, Federal University of Health Sciences, Otukpo, Benue State, Nigeria
4Renewable and Sustainable Energy Research Centre, Sol Plaatje University, Private Bag X 5008, Kimberly, 8300, South Africa
5 National Institute for Theoretical and Computational Sciences, NITheCS, Gauteng, 2000, South Africa

Abstract
The lead-based perovskite solar cells are a third-generation photovoltaic technology with high power conversion efficiency and low cost. However, they suffer toxicity and stability issues, which downplay their efficiency and hinder their industrial production and commercialization. Therefore, the exploration of lead-free perovskite absorber materials with high stability is a high priority to advance commercial applications of perovskite solar cells. This study uses SCAPS-1D simulations to optimize an eco-friendly, lead-free perovskite solar cell cubic KGeCl3 material. We systematically investigated the impact of absorber layer thickness (200–1000 nm), and defect density on device performance. The effect of the absorber layer thickness and defect density achieved a power conversion efficiency of 19.93% with an open-circuit voltage of 1.55 V, a short-circuit current density of 17.79 mA/cm², and a fill factor of 72.16%. These results demonstrate that careful optimization of the absorber defect density (to <1015 cm⁻³) is critical for matching the performance of lead-based counterparts Sn-Pb perovskite solar cells, with the power conversion efficiency of 21.7%. This work provides a roadmap for fabricating high-efficiency, non-toxic perovskite solar cells.