Ultrafast Terahertz Probes of Charge Transfer and Recombination Pathway of CH₃NH₃PbI₃ Perovskites

【摘要】 We use transient terahertz photoconductivity measurements to demonstrate that upon optical excitation of CH₃NH₃PbI₃ perovskite, the hole transfer from CH₃NH₃PbI₃ into the organic hole-transporting material（HTM）Spiro-OMe TAD occurs on a sub-picosecond timescale. Second-order recombination is the dominant decay pathway at higher photo-excitation fluences as observed in neat CH₃NH₃PbI₃ films. In contrast, under similar experimental conditions, second-order recombination weakly contributes the relatively slow recombination between the electrons in the perovskite and the injected holes in HTM, as a loss mechanism at the CH₃NH₃PbI₃/Spiro-OMe TAD interface. Our results offer insights into the intrinsic photophysics of CH₃NH₃PbI₃-based perovskites with direct implications for photovoltaic devices and optoelectronic applications.更多还原

【Abstract】 We use transient terahertz photoconductivity measurements to demonstrate that upon optical excitation of CH₃NH₃PbI₃ perovskite, the hole transfer from CH₃NH₃PbI₃ into the organic hole-transporting material（HTM）Spiro-OMe TAD occurs on a sub-picosecond timescale. Second-order recombination is the dominant decay pathway at higher photo-excitation fluences as observed in neat CH₃NH₃PbI₃ films. In contrast, under similar experimental conditions, second-order recombination weakly contributes the relatively slow recombination between the electrons in the perovskite and the injected holes in HTM, as a loss mechanism at the CH₃NH₃PbI₃/Spiro-OMe TAD interface. Our results offer insights into the intrinsic photophysics of CH₃NH₃PbI₃-based perovskites with direct implications for photovoltaic devices and optoelectronic applications.更多还原