Ultrafast Terahertz Probes of Charge Transfer and Recombination Pathway of CH ₃ NH ₃ PbI ₃ Perovskites

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-OMeTAD 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-OMeTAD interface. Our results offer insights into the intrinsic photophysics of CH3NH3PbI3-based perovskites with direct implications for photovoltaic devices and optoelectronic applications.

The structural, electronic, and optical properties of organic–inorganic mixed halide perovskites CH 3 NH 3 Pb(I 1− y X y ) 3 (

“…Organic-inorganic perovskites based on the metal hybrids solar cells have attracted wide photovoltaic research due to its flexibility, easy manufacture, lowcost and high optical absorption efficiency to scientific and industrial applications. [25][26][27][28][29][30][31][32][33][34][35][36] For the novel organic-inorganic perovskite materials, many efforts have been devoted to the replacement of A + , B 2+ , and X − by other ions to exploring their outstanding performance. [2,27] The hybrid organic-inorganic perovskites show excellent optical properties in recent experimental measurements and theoretical calculations.…”

Terahertz Modulation and Ultrafast Characteristic of Two-Dimensional Lead Halide Perovskites

“…When the semiconductor films are pumped by external light, for example, the THz waves passing through them would be modulated due to the existence of photogenerated carriers. Moreover, the more photogenerated carriers, the greater the modulation depth of the device [ 26 ]. Thus, the application prospects of the materials can be further developed according to their modulation depths and speeds.…”

High, Multiple, and Nonvolatile Polarizations in Organic–Inorganic Hybrid [(CH3)3(CH2CH2Cl)N]2InCl5·H2O for Memcapacitor

“…From the perspective of facilitating ion migration, a variety of ionic conductors with small ionic radii such as proton (H + ), Li + , or Na + serve as candidates. − Among them, the proton stands out as the most attractive candidate due to its small size and its propensity to not form harmful metal dendrites that may block the migration pathways. Organic–inorganic metal halide hybrids are a new class of functional materials that usually consist of a relatively rigid inorganic framework and flexible organic motifs residing inside voids of the framework. − This structural feature allows a large structural tolerance and relatively weak interactions between anions and cations compared with pure organic or inorganic materials, providing ample space for long-range proton migration. Among these, the polyhedron with indium as central ions and halogen and water molecules as ligands [In X m (H 2 O) n , X = halogen anions, m + n = 6] are well known and have been extensively studied.…”