Simulation and modeling of a new CsSnI₃ solar cell structure: a numerical study

Abstract This study explores the development of a lead-free CsSnI 3 -based solar cell structure aimed at enhancing charge stability, transport, and overall performance. A device configuration of Spiro-OMeTAD/CsSnI 3 /CH 3 NH 3 SnI 3 /PCBM/ITO was simulated using the SCAPS-1D program. Simulation results, performed under standard illumination conditions (1000 W m −2 ) at 300 K, identified an optimal CsSnI 3 absorber layer thickness of 300 nm, corresponding to a defect density ranging between 10 12 cm −3 and 10 14 cm −3 . This optimized configuration not only enhances device performance but also reduces the long-term environmental toxicity associated with tin. Through a detailed analysis of parasitic resistances, the optimal shunt resistance ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi>R</mml:mi> <mml:mrow> <mml:mrow> <mml:mtext>shunt</mml:mtext> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:mrow> </mml:math> ) was found to be 10 6 Ω.cm 2 , with a series resistance ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi>R</mml:mi> <mml:mrow> <mml:mrow> <mml:mtext>Series</mml:mtext> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:mrow> </mml:math> ) approaching zero. Under these conditions, the device achieved a fill factor ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mtext>FF</mml:mtext> </mml:mrow> </mml:mrow> </mml:math> ) of 71.99%, power conversion efficiency ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>η</mml:mi> </mml:mrow> </mml:math> ) of 19.47%, short-circuit current density ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi>J</mml:mi> <mml:mrow> <mml:mrow> <mml:mtext>SC</mml:mtext> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:mrow> </mml:math> ) of 31.092 mA cm −2 , and open-circuit voltage ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi>V</mml:mi> <mml:mrow> <mml:mrow> <mml:mtext>OC</mml:mtext> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:mrow> </mml:math> ) of 0.87 V. After optimizing the doping density, the performance was further enhanced, yielding <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi>V</mml:mi> <mml:mrow> <mml:mrow> <mml:mtext>OC</mml:mtext> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:mrow> </mml:math> = 0.9919 V, <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:msub> <mml:mi>J</mml:mi> <mml:mrow> <mml:mrow> <mml:mtext>SC</mml:mtext> </mml:mrow> </mml:mrow> </mml:msub> </mml:mrow> </mml:mrow> </mml:math> = 32.5664 mA cm −2 , <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mtext> FF</mml:mtext> </mml:mrow> </mml:mrow> </mml:math> = 71.64%, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mi>η</mml:mi> </mml:mrow> </mml:math> = 23.14%. These results closely align with the experimental findings reported by NREL in 2024. This work demonstrates significant advancements in the development of high-efficiency, environmentally friendly, lead-free CsSnI 3 solar cells, providing valuable insights for future research and practical applications.