New insight into the ultra-long lifetime of excitons in organic–inorganic perovskite: Reverse intersystem crossing

Meng, Guanghao; Shi, Yantao; Wang, Xiangyuan; Wang, Wei; Wang, Shufeng; Ji, Min; Hao, Ce

doi:10.1016/j.jechem.2017.10.018

Cited by 11 publications

(12 citation statements)

References 41 publications

(54 reference statements)

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“…Quasi-2D layered perovskites have recently attracted enormous interest as light emitters due to their outstanding photophysical and electrical properties. Due to their inherent quantum confinement and reduced dielectric screening, layered perovskites offer strong exciton binding energy and subsequent stable excitonic medium even at room temperature. − In addition, their small exchange energy (Δ E ST ) enables efficient harvesting of triplet excitons, − which are effectively diffused into the small subpopulation of radiative domains. − Consequently, photoluminescence quantum yield (PLQY) has increased to near unity, , and record-high external quantum efficiency (EQE) over 20% was achieved . Furthermore, modification of their halide composition offers an effective pathway for the fine-tuning of their emission wavelength.…”

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confidence: 99%

Spectral Instability of Layered Mixed Halide Perovskites Results from Anion Phase Redistribution and Selective Hole Injection

et al. 2020

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Despite the ability to precisely tune their bandgap energies, mixed halide perovskites (MHPs) suffer from significant spectral instability, which obstructs their utilization for the rational design of light-emitting diodes. Here, we investigate the origin of the electroluminescence peak shifts in layered MHPs containing bromide and iodide. X-ray diffraction and steady-state absorption measurements prove effective integration of iodide into the cubic lattice and the spatially uniform distribution of halides in the ambient environment. However, the applied electric field during the device operation is found to drive the systematic halide migration. Quantum mechanical density functional theory calculations reveal that the different activation energies required for directional ion hopping lead to the redistribution of anions. In-depth analyses of the electroluminescence spectra indicate that the spectral shifting rate is dependent on the drift velocity of halides. Finally, it is suggested from our study that the dominant red emission is ascribed to the thermodynamically favorable selective hole injection. Our mechanistic study provides insights into the fundamental reason for the spectral instability of devices based on MHPs.

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confidence: 99%

Spectral Instability of Layered Mixed Halide Perovskites Results from Anion Phase Redistribution and Selective Hole Injection

et al. 2020

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“…That is, the charge extraction rate was inversely proportional to ΔE g . 44 Therefore, the photovoltaic performance of PSCs based on Sn/S = 1:3 was better than that of PSCs based on Sn/S = 1:2 ETL.…”

Section: ■ Results and Discussionmentioning

confidence: 91%

“…The smaller that Δ E g difference was, the more that the transfer rate of the electrons increased. That is, the charge extraction rate was inversely proportional to Δ E g . Therefore, the photovoltaic performance of PSCs based on Sn/S = 1:3 was better than that of PSCs based on Sn/S = 1:2 ETL.…”

Section: Resultsmentioning

confidence: 97%

Significantly Enhanced V-oc and Efficiency in Perovskite Solar Cells through Composition Adjustment of SnS₂ Electron Transport Layers

Gao

Liu

Meng

et al. 2020

ACS Sustainable Chem. Eng.

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The energy level alignment (ELA) between electron transport layers (ETLs) and perovskite layers would affect the photovoltaic performance of perovskite solar cells (PSCs), especially for the open-circuit voltage (V oc). However, systematic investigations were rarely reported. In this letter, a series of SnS2/SnS composite ETLs were in situ synthesized, where the doping of SnS was used to adjust the energy level of SnS2 nanosheets. Results showed that electrons could be transferred from perovskite layers to ETLs; even the conduction band (CB) of ETLs was a little higher than that of perovskite layers. In comparison with PSCs based on SnS2 ETLs, the power conversion efficiency (PCE) of PSCs based on SnS2/SnS was enhanced by 27.95% (from 14.13% to 18.08%) with a higher V oc promotion (from 0.94 to 1.08 V). A corresponding explanation and working principle have been proposed. In addition, a stability test demonstrated that PSCs based on SnS2/SnS ETLs possessed much better stability than that of traditional PSCs based on TiO2 ETLs because of the strong interaction of Pb and S. This work proposes a promising future for reducing the V oc loss and improving the stability of perovskites.

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“…Although the three perovskite materials are organic–inorganic hybrid materials, organic cations greatly affect the electronic structures and photovoltaic properties , of perovskites. In addition, the singlet-triplet splitting energies Δ E st of CH 3 NH 3 PbI 3 were calculated to be 82 and 47 meV for orthonormal and tetragonal phases, respectively . The Δ E st values of organic molecules have been reported to be from 100 to 200 meV approximately, much larger than those of inorganic materials .…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the singlet-triplet splitting energies ΔE st of CH 3 NH 3 PbI 3 were calculated to be 82 and 47 meV for orthonormal and tetragonal phases, respectively. 26 The ΔE st values of organic molecules have been reported to be from 100 to 200 meV approximately, much larger than those of inorganic materials. 27 The existence of a narrow band and the strong electron−phonon interactions, along with the structural disorder of the system, enables the carriers to hop between adjacent localized states, leading to a thermally activated hopping mechanism.…”

Section: ■ Introductionmentioning

confidence: 99%

Theoretical Insights into the Carrier Mobility Anisotropy of Organic–Inorganic Perovskite ABI₃ (A = CH₃NH₃ and HC(NH₂)₂; B = Pb and Sn)

Meng

Hao

et al. 2021

J. Phys. Chem. C

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High mobility, which is closely relevant to crystal structures, is one of the predominant advantages of organic–inorganic halide perovskites. However, the carrier mobility anisotropies for photoelectric materials HC(NH2)2SnI3, HC(NH2)2PbI3, and CH3NH3SnI3 parallel to the representative crystal planes are still unknown. According to the density functional theory and Marcus theory, we focus on carrier mobility anisotropy by simulating the intermolecular electronic coupling integral V and the internal reorganization energy λ parallel to different low-index crystal planes. Results indicate that the electrons and holes of HC(NH2)2PbI3 exhibit transport orientation consistency along the (101), (010), (111), and (001) crystal planes. However, inconsistency was observed along the (110) crystal planes (an angle of 65° between electron and hole movements). The electrons and holes in HC(NH2)2SnI3 reflect transport orientation consistency along the (001) and (101) crystal planes, while inconsistency was observed along the (110) and (111) crystal planes (the angles fluctuate from 40 to 65° between the carrier movements). The carriers in CH3NH3SnI3 exhibit transport orientation consistency along the (110) and (101) crystal planes, while inconsistencies were observed along the (010), (001), and (111) crystal planes (the angles fluctuate from 45 to 65° between the carrier transport). This study emphasizes the theoretical guidance of controllable oriented fabrication for perovskites.

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New insight into the ultra-long lifetime of excitons in organic–inorganic perovskite: Reverse intersystem crossing

Cited by 11 publications

References 41 publications

Spectral Instability of Layered Mixed Halide Perovskites Results from Anion Phase Redistribution and Selective Hole Injection

Spectral Instability of Layered Mixed Halide Perovskites Results from Anion Phase Redistribution and Selective Hole Injection

Significantly Enhanced V-oc and Efficiency in Perovskite Solar Cells through Composition Adjustment of SnS₂ Electron Transport Layers

Theoretical Insights into the Carrier Mobility Anisotropy of Organic–Inorganic Perovskite ABI₃ (A = CH₃NH₃ and HC(NH₂)₂; B = Pb and Sn)

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New insight into the ultra-long lifetime of excitons in organic–inorganic perovskite: Reverse intersystem crossing

Cited by 11 publications

References 41 publications

Spectral Instability of Layered Mixed Halide Perovskites Results from Anion Phase Redistribution and Selective Hole Injection

Spectral Instability of Layered Mixed Halide Perovskites Results from Anion Phase Redistribution and Selective Hole Injection

Significantly Enhanced V-oc and Efficiency in Perovskite Solar Cells through Composition Adjustment of SnS2 Electron Transport Layers

Theoretical Insights into the Carrier Mobility Anisotropy of Organic–Inorganic Perovskite ABI3 (A = CH3NH3 and HC(NH2)2; B = Pb and Sn)

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Significantly Enhanced V-oc and Efficiency in Perovskite Solar Cells through Composition Adjustment of SnS₂ Electron Transport Layers

Theoretical Insights into the Carrier Mobility Anisotropy of Organic–Inorganic Perovskite ABI₃ (A = CH₃NH₃ and HC(NH₂)₂; B = Pb and Sn)