Quantum Efficiency Optimization of Tin-Based Perovskite Solar Cells via Graded Bandgap Profiling

International Journal of Physics | Vol. 8, No. 6, June 2017 | pp. 41–48

DOI: 10.46882/2017/IJP/000086

Research Article

Title: Quantum Efficiency Optimization of Tin-Based Perovskite Solar Cells via Graded Bandgap Profiling

Names of Authors: H. K. Tanaka¹, S. P. McCarthy²

Authors’ Affiliations: ¹Department of Quantum Engineering, Nagoya University, Nagoya, Japan; ²European Organization for Nuclear Research (CERN), Geneva, Switzerland

Abstract: Lead-free tin-based perovskite solar cells present a highly promising, environmentally friendly pathway for low-cost, high-efficiency photovoltaics. This paper presents a comprehensive numerical model to optimize the internal quantum efficiency of methylammonium tin iodide (MASnI3) perovskite solar cells using a graded bandgap design. 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 1.30 eV to 1.65 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 15.0 ns are introduced, the optimized graded device yields a short-circuit current density of 28.4 mA/cm² and an open-circuit voltage of 0.88 V. This results in a maximum power conversion efficiency of 18.4%, representing a significant improvement over the 13.2% 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 25.0%. These insights provide practical guidelines for engineering high-performance, eco-friendly photovoltaics.

Keywords: Perovskite solar cells; graded bandgap; quantum efficiency; charge transport; numerical modeling; tin-based photovoltaics

Manuscript Timeline: Received: March 02, 2017; Revised: April 14, 2017; Accepted: May 02, 2017; Published: June 12, 2017

Citation: Tanaka, H. K., & McCarthy, S. P. (2017). Quantum Efficiency Optimization of Tin-Based Perovskite Solar Cells via Graded Bandgap Profiling. International Journal of Physics, 8(6), 41–48.

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