International Journal of Physics | Vol. 17, No. 8, August 2026 | pp. 73–80
DOI: 10.46882/2026/IJP/000198
Research Article
Title: Thermodynamic Analysis and Efficiency Optimization of Perovskite Intermediate Band Solar Cells
Names of Authors: H. K. Tanaka¹, E. C. Dupont²
Authors’ Affiliations:
¹ Department of Quantum Engineering, Nagoya University, Nagoya, Japan
² Laboratory of Photovoltaics, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
Abstract: Intermediate band solar cells (IBSCs) present a highly promising route to exceed the Shockley-Queisser efficiency limit of single-junction photovoltaic devices. This paper presents a detailed thermodynamic model to evaluate the conversion efficiency limit of formamidinium lead iodide intermediate band solar cells. We systematically evaluated the impacts of radiative and non-radiative recombination rates on device performance under full solar concentration (46,200 suns) and standard one-sun illumination. Our numerical calculations reveal an ideal thermodynamic efficiency limit of 63.2% under full concentration when non-radiative losses are completely suppressed. However, when standard Shockley-Read-Hall non-radiative lifetimes of 1.5 ns are introduced, the maximum achievable efficiency drops sharply to 38.5%. To mitigate these non-radiative losses, we simulated a graded band gap host structure that enhances carrier extraction from the intermediate band to the conduction band. The optimized device design yields a short-circuit current density of 39.4 mA/cm² and an open-circuit voltage of 1.12 V under one-sun conditions. We also analyzed the thermal stability of the intermediate band population between 200.0 K and 400.0 K. The results demonstrate that thermal carrier escape significantly degrades sub-bandgap photon absorption above 280.0 K. This degradation emphasizes the critical need for deep potential wells exceeding 0.3 eV. These detailed thermodynamic insights provide valuable engineering guidelines for structural optimization in third-generation high-efficiency perovskite photovoltaics.
Keywords: Photovoltaics; Perovskites; Intermediate band solar cells; Thermodynamic efficiency; Recombination lifetime; Solar energy
Manuscript Timeline: Received: April 18, 2026 / Revised: May 28, 2026 / Accepted: June 20, 2026 / Published: August 14, 2026
Citation: Tanaka, H. K., & Dupont, E. C. (2026). Thermodynamic Analysis and Efficiency Optimization of Perovskite Intermediate Band Solar Cells. International Journal of Physics, 17(8), 73–80.
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