World Journal of Condensed Matter Physics, 2023, 13, 90-104 https://www.scirp.org/journal/wjcmp ISSN Online: 2160-6927 ISSN Print: 2160-6919 DOI: 10.4236/wjcmp.2023.133006 Aug. 4, 2023 90 World Journal of Condensed Matter Physics A Study on the Efficiency Gain of CsSnGeI 3 Solar Cells with Graphene Doping Mohammed M. Shabat 1,2 , Guillaume Zoppi 2 1 Department of Physics, The Islamic University of Gaza, Gaza Strip, Palestine 2 Department of Mathematics, Physics & Electrical Engineering, Northumbria University, Newcastle upon Tyne, UK Abstract This paper presents a newly designed ultra-thin, lead-free, and all-inorganic solar cell structure. The structure was optimized using the SCAPS-1D simu- lator, incorporating solid-state layers arranged as n-graphene/CsSnGeI 3 /p- graphene. The objective was to investigate the potential of utilizing n-graphene as the electron transport layer and p-graphene as the hole transport layer to achieve maximum power conversion efficiency. Various materials for the electron transport layer were evaluated. The optimized cell structure achieved a maximum power conversion efficiency of 20.97%. The proposed solar cell structure demonstrates promising potential as an efficient, inorganic photo- voltaic device. These findings provide important insights for developing and optimizing inorganic photovoltaic cells based on CsSnGeI 3 , with n-graphene electron transport layers and p-graphene hole transport layers. Keywords Perovskite Solar Cells, Efficiency Gain, CsSnGeI 3 Solar Cells, Graphene Doping, Photovoltaics, Thin-Film Solar Cells, Energy Conversion 1. Introduction The photovoltaic (PV) market has been growing exponentially for decades with 1 TW of cumulative PV installations reported in 2022 [1] with >1 TW projected to be added annually from 2030 [2]. Perovskite solar cells (PSCs) [3] [4] [5] [6] [7] have gained significant attention due to their high-power conversion effi- ciency and unique properties. Perovskites are oxides of the chemical formula ABX 3 , where A and B are two cations of different sizes, and X is an anion to bal- ance the charges. Perovskite materials [8]-[13] have high absorption coefficients, low-temperature processing, tuneable bandgaps, long charge carrier diffusion How to cite this paper: Shabat, M.M. and Zoppi, G. (2023) A Study on the Efficiency Gain of CsSnGeI 3 Solar Cells with Graphene Doping. World Journal of Condensed Mat- ter Physics, 13, 90-104. https://doi.org/10.4236/wjcmp.2023.133006 Received: May 19, 2023 Accepted: August 1, 2023 Published: August 4, 2023 Copyright © 2023 by author(s) and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0). http://creativecommons.org/licenses/by/4.0/ Open Access