Optimizing Charge Transport Layers to Enhance the Performance of Lead-Free RbGeI3 Perovskite Solar Cells: A Comprehensive Analysis of ETL and HTL Engineering

Md Selim Reza; Avijit Ghosh; Hala A Ibrahium; Md Baharul Islam; Mehedi Hasan Apu; Md Shamim Reza; Muhammad Ihsan Ibn Rahim; Mst Mohona Akter

doi:10.1021/acs.langmuir.5c00499

Optimizing Charge Transport Layers to Enhance the Performance of Lead-Free RbGeI₃ Perovskite Solar Cells: A Comprehensive Analysis of ETL and HTL Engineering

Langmuir. 2025 Mar 25;41(11):7865-7885. doi: 10.1021/acs.langmuir.5c00499. Epub 2025 Mar 14.

Authors

Md Selim Reza¹, Avijit Ghosh¹, Hala A Ibrahium², Md Baharul Islam³, Mehedi Hasan Apu⁴, Md Shamim Reza¹, Muhammad Ihsan Ibn Rahim⁵, Mst Mohona Akter⁶

Affiliations

¹ Department of Electrical and Electronic Engineering, Begum Rokeya University, Rangpur 5400, Bangladesh.
² Department of Biology, Faculty of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia.
³ Department of Electrical and Computer Engineering, Lamar University, Beaumont, Texas 77710, United States.
⁴ Masters in Management Information Systems, Lamar University, Beaumont, Texas 77710, United States.
⁵ Department of Physics, University of Louisiana at Lafayette, 104 E University Avenue, Lafayette, Louisiana 70504, United States.
⁶ Diploma in Nursing Science and Midwifery, Jamalpur Nursing and Midwifery College, Jamalpur 2000, Bangladesh.

PMID: 40085818
DOI: 10.1021/acs.langmuir.5c00499

Abstract

This study investigates innovative hybrid perovskite solar cells using rubidium-germanium-iodide (RbGeI₃) as the substrate, incorporating various hole transport layers like Cu₂O, CuO, and SnSe, and wide-bandgap chalcogenide electron transport layers (ETLs) like IGZO, WS₂, In₂S₃, and ZnSe. After selecting IGZO as the optimal ETL, its depth was optimized using the SCAPS-1D simulator to evaluate device performance. Three device configurations were examined: device-I (Al/FTO/IGZO/RbGeI₃/Cu₂O/Ni), device-II (Al/FTO/IGZO/RbGeI₃/CuO/Ni), and device-III (Al/FTO/IGZO/RbGeI₃/SnSe/Ni), with a detailed analysis of the doping concentration, thickness of the layer, density of defect, operational temperature, and interface defects. Benchmarks for efficient RbGeI₃-based SCs were set, with device I achieving the highest power conversion efficiency of 33.84%, fill factor of 86.78%, open-circuit voltage (V_OC) of 1.13 V, and short-circuit current density (J_SC) of 34.54 mA/cm². Devices II and III recorded PCEs of 25.91% and 25.21%, respectively. Additionally, series-shunt resistances, generation-recombination rates, carrier dynamics, and quantum efficiency (QE %) were analyzed. Device I shows substantial potential for high-efficiency hybrid perovskite photovoltaic systems based on RbGeI₃.