The Challenges of Accurate <i> J _0e </i> Determination on Modern Solar Cells: A Sensitivity Study of Input Parameter Uncertainty

Carrier recombination lifetime parameters, including effective lifetime (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">τ</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub>), emitter saturation current density (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_0e</i>), and bulk lifetime (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">τ</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">bulk</sub>) on silicon photovoltaic cells, are essential quality metrics for sample characterization and enable power loss analyses that drive process optimization decisions. The carrier recombination lifetime of cells is derived from measured Suns-Voc data based on sample-specific inputs of substrate thickness and resistivity. This work presents a sensitivity analysis of the carrier recombination lifetime measurements on silicon photovoltaic cells due to uncertainty in input thickness and resistivity and proposes best practices to reduce these uncertainties to achieve results with a high level of confidence. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_0e</i> uncertainties less than 1 fA/cm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> can be achieved with measurement or knowledge of input parameters beyond what is given on a specification sheet.