Advanced space-charge-limited current model for analyzing fermi level shift in the bandgap of halide perovskites

Abstract

Understanding how charge carriers behave in semiconductors is key to improving next-generation optoelectronic devices. Here we introduce an advanced space-charge-limited current model that enables detailed extraction of mobility, charge carrier concentrations, and Fermi level position from voltage- and energy-dependent analysis. Applying this model to two promising halide perovskites, methylammonium lead bromide and methylammonium lead iodide, we observe a strong photoresponse, with significant increases in microscopic mobility and free carrier density under illumination. Interestingly, the behavior of trapped charges and Fermi level shifts differs between the two materials, revealing distinct transport mechanisms. This model offers a powerful tool for characterizing semiconductors and could accelerate the development of more efficient light-sensitive devices.Understanding how charge carriers behave in semiconductors is key to improving next-generation optoelectronic devices. Here we introduce an advanced space-charge-limited current model that enables detailed extraction of mobility, charge carrier concentrations, and Fermi level position from voltage- and energy-dependent analysis. Applying this model to two promising halide perovskites, methylammonium lead bromide and methylammonium lead iodide, we observe a strong photoresponse, with significant increases in microscopic mobility and free carrier density under illumination. Interestingly, the behavior of trapped charges and Fermi level shifts differs between the two materials, revealing distinct transport mechanisms. This model offers a powerful tool for characterizing semiconductors and could accelerate the development of more efficient light-sensitive devices.