Relative Permittivity and Optoelectronic Performances of Halide Perovskites: Study of Combined First‐Principles Simulation and Combinatorial Synthesis

Owing to their excellent optoelectronic properties, halide perovskites (HPs) have garnered significant attention in the field of optoelectronics. However, conventional HPs‐based optoelectronic devices primarily are fabricated using solution‐based processes, implying that extremely time‐consuming needs to individually synthesize their composition‐dependent optoelectronic properties. This study demonstrates the feasibility of combining first‐principles simulations with combinatorial synthesis, comparing the effects of HP properties on optoelectronic devices using this combined approach. The first‐principles simulations confirm that increasing the ratio of small halide ions increased the band gap by k·p perturbation theory and harmonic oscillator models. By fabricating HP thin films with compositional gradients using combinatorial synthesis, it is confirmed that an increase in band gap corresponds to a decrease in static relative permittivity. Furthermore, HP‐based optoelectronic devices are fabricated to measure their photoelectric conversion efficiency and responsivity based on the simulated and measured relative permittivity, including time‐resolved photoluminescence. The findings demonstrate the influence of the relative permittivity on device performance, elucidating the relationship between band structure and relative permittivity. Therefore, in this study, the potential of combining first‐principles simulations with combinatorial synthesis is confirmed by comparing the relative permittivity characteristics of optoelectronics developed using this combined approach.