Analytical Modeling of Solar Cells Having Short Lifetime Materials: Application to Kesterite Solar Cells

Abstract

Solar cells fabricated from short-carrier lifetime materials face efficiency limitations because of high recombination rates, particularly within the depletion region. Kesterite solar cells offer a promising alternative to conventional solar cells but suffer from short-carrier lifetimes. This work introduces a comprehensive analytical model applicable to such solar cells. We developed a novel approach to accurately represent the recombination rates of the carriers within the depletion region using a Gaussian function. This model overcomes the limitations of existing approximations and enables more precise dark current calculations. Additionally, we employed a fully analytical generation rate calculation based on the transfer matrix method for accurate photocurrent determination. The effectiveness of this model was validated by comparing its results with simulated and experimental data for kesterite solar cells, demonstrating excellent agreement in dark current and photocurrent, with maximum percentage errors of 1.9% and 1.7%, respectively. Beyond accuracy, the model also achieved a 75-fold improvement in computation speed compared to finite element method simulations. This highlights the effectiveness of the model in capturing the complex recombination processes within kesterite solar cells and in providing a valuable tool for understanding and optimizing the performance of solar cells based on short-lifetime materials, particularly kesterite-based devices with one-sided junction characteristics.