International Journal of Physics | Vol. 6, No. 7, July 2015 | pp. 49–56
DOI: 10.46882/2015/IJP/000063
Research Article
Title: Quantum Efficiency Optimization of Perovskite Solar Cells via Graded Bandgap Architecture
Names of Authors: H. K. Tanaka¹, C. M. Brauer²
Authors’ Affiliations: ¹Department of Quantum Engineering, Nagoya University, Nagoya, Japan; ²Institut für Physik, Humboldt-Universität zu Berlin, Berlin, Germany
Abstract: Perovskite solar cells (PSCs) have emerged as highly promising candidates for low-cost, high-efficiency photovoltaics. This paper presents a detailed numerical model to optimize the internal quantum efficiency of methylammonium lead iodide (MAPbI3) perovskite solar cells using a graded bandgap architecture. We systematically evaluated the impacts of carrier recombination lifetimes and interface defect densities on device performance parameters under standard one-sun illumination (AM 1.5G, 100.0 mW/cm²). Our numerical calculations reveal that grading the iodine-to-bromine ratio creates a linear bandgap profile (varying from 1.55 eV to 1.80 eV), which generates a built-in electric field. This built-in field accelerates charge separation and reduces radiative recombination rates. When standard recombination lifetimes of 20.0 ns are introduced, the optimized graded device yields a short-circuit current density of 24.8 mA/cm² and an open-circuit voltage of 1.18 V. This results in a maximum power conversion efficiency of 23.4%, representing a significant improvement over the 18.2% efficiency calculated for the uniform bandgap control cell. We also analyzed the thermal stability of the device between 280.0 K and 360.0 K, demonstrating that the graded structure reduces thermal efficiency degradation by 30.0%. These insights provide practical guidelines for engineering high-performance perovskite photovoltaics.
Keywords: Perovskite solar cells; graded bandgap; quantum efficiency; charge transport; numerical modeling; photovoltaics
Manuscript Timeline: Received: March 20, 2015; Revised: May 05, 2015; Accepted: May 28, 2015; Published: July 15, 2015
Citation: Tanaka, H. K., & Brauer, C. M. (2015). Quantum Efficiency Optimization of Perovskite Solar Cells via Graded Bandgap Architecture. International Journal of Physics, 6(7), 49–56.
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