Ligand-assisted cation-exchange engineering for high-efficiency colloidal Cs1−xFAxPbI3 quantum dot solar cells with reduced phase segregation

Hao, Mengmeng; Bai, Yang; Zeiske, Stefan; Ren, Long; Liu, Junxian; Yuan, Yongbo; Zarrabi, Nasim; Cheng, Ningyan; Ghasemi, Mehri; Chen, Peng; Lyu, Miaoqiang; He, Dongxu; Yun, Jung‐Ho; Du, Yi; Wang, Yun; Ding, Shanshan; Armin, Ardalan; Meredith, Paul; Liu, Gang; Cheng, Hui‐Ming; Wang, Luyao

doi:10.1038/s41560-019-0535-7

Cited by 489 publications

(583 citation statements)

References 48 publications

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“…8 To date, the record certified cesium lead halide QD-based solar cells have demonstrated a power conversion efficiency of 16.6%. 9 The optoelectronic properties of QDs are highly dependent on their surface coordination chemistry. [10][11][12][13][14] For instance, surface ligands play a critical role in passivating mid-gap electronic trap states and enabling high PLQY.…”

Section: Introductionmentioning

confidence: 99%

Surface Termination of CsPbBr₃ Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy

et al. 2020

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Cesium lead halide perovskite quantum dots (QDs) have gained significant attention as next-generation optoelectronic materials; however, their properties are highly dependent on their surface chemistry. The surfaces of cuboidal CsPbBr3 QDs have been intensively studied by both theoretical and experimental techniques, but fundamental questions still remain about the atomic termination of the QDs. The binding sites and modes of ligands at the surface remain unproven. Herein, we demonstrate that solid-state NMR spectroscopy allows the unambiguous assignments of organic surface ligands via 1H, 13C, and 31P NMR. Surface-selective 133Cs solid-state NMR spectra show the presence of an additional 133Cs NMR signal with a unique chemical shift that is attributed to Cs atoms terminating the surface of the particle and which are likely coordinated by carboxylate ligands. Dipolar dephasing curves that report on the distance between the surface ammonium ligands and Cs and Pb were recorded using double resonance 1H{133Cs} and 1H{207Pb} RESPDOR experiments. Model QD surface slabs with different possible surface terminations were generated from the CsPbBr3 crystal structure and theoretical RESPDOR dipolar dephasing curves considering all possible 1H-133Cs/207Pb spin pairs were then calculated. Comparison of the calculated and experimental RESPDOR curves indicates the particles are CsBr terminated (not PbBr2 terminated), with alkylammonium ligands situated within surface Cs vacancies, consistent with the surface-selective 133Cs NMR experiments. These results highlight the utility of high-resolution solid-state NMR spectroscopy for studying ligand binding and the surface structure of nanomaterials.

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Section: Introductionmentioning

confidence: 99%

Surface Termination of CsPbBr₃ Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy

et al. 2020

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“…Various fundamental studies have shown that the organic cations in the perovskite lattice (MA or FA) enhance carrier lifetimes because the rotation of asymmetrical cations in the lead halide cages increases orbital overlap and promotes large polaron formation. [120][121][122][123][124] The implication of the Figure 15. 4-Vinylbenzyldimethyloctadecylammonium chloride as a polymerizable ligand for MAPbBr 3 nanocrystals.…”

Section: A-site Dopingmentioning

confidence: 99%

Lead Halide Perovskite Nanocrystals: Room Temperature Syntheses toward Commercial Viability

Brown

Bahulayan

Jiang

et al. 2020

Advanced Energy Materials

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In this progress report, recent improvements to the room temperaturesyntheses of lead halide perovskite nanocrystals (APbX3, X = Cl, Br, I) are assessed, focusing on various aspects which influence the commercial viability of the technology. Perovskite nanocrystals can be prepared easily from low‐cost precursors under ambient conditions, yet they have displayed near‐unity photoluminescence quantum yield with narrow, highly tunable emission peaks. In addition to their impressive ambipolar charge carrier mobilities, these properties make lead halide perovskite nanocrystals very attractive for light‐emitting diode (LED) applications. However, there are still many practical hurdles preventing commercialization. Recent developments in room temperature synthesis and purification protocols are reviewed, closely evaluating the suitability of particular techniques for industry. This is followed by an assessment of the wide range of ligands deployed on perovskite nanocrystal surfaces, analyzing their impact on colloidal stability, as well as LED efficiency. Based on these observations, a perspective on important future research directions that can expedite the industrial adoption of perovskite nanocrystals is provided.

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“…General applicability was demonstrated by PM6:Y6‐based OSCs whose PCE was improved from 15.4% to 16.6% with the addition of PQDs, which was similar to the record PCE of the PQD solar cell (16.6%). [ 48 ]…”

Section: Figurementioning

confidence: 99%

High‐Efficiency Perovskite Quantum Dot Hybrid Nonfullerene Organic Solar Cells with Near‐Zero Driving Force

et al. 2020

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To take advantages of the intense absorption and fluorescence, high charge mobility, and high dielectric constant of CsPbI3 perovskite quantum dots (PQDs), PQD hybrid nonfullerene organic solar cells (OSCs) are fabricated. Addition of PQDs leads to simultaneous enhancement of open‐circuit voltage (VOC), short‐circuit current density (JSC), and fill factor (FF); power conversion efficiencies are boosted from 11.6% to 13.2% for PTB7‐Th:FOIC blend and from 15.4% to 16.6% for PM6:Y6 blend. Incorporation of PQDs dramatically increases the energy of the charge transfer state, resulting in near‐zero driving force and improved VOC. Interestingly, at near‐zero driving force, the PQD hybrid OSCs show more efficient charge generation than the control device without PQDs, contributing to enhanced JSC, due to the formation of cascade band structure and increased molecular ordering. The strong fluorescence of the PQDs enhances the external quantum efficiency of the electroluminescence of the active layer, which can reduce nonradiative recombination voltage loss. The high dielectric constant of the PQDs screens the Coulombic interactions and reduces charge recombination, which is beneficial for increased FF. This work may open up wide applicability of perovskite quantum dots and an avenue toward high‐performance nonfullerene solar cells.

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Ligand-assisted cation-exchange engineering for high-efficiency colloidal Cs1−xFAxPbI3 quantum dot solar cells with reduced phase segregation

Cited by 489 publications

References 48 publications

Surface Termination of CsPbBr₃ Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy

Surface Termination of CsPbBr₃ Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy

Lead Halide Perovskite Nanocrystals: Room Temperature Syntheses toward Commercial Viability

High‐Efficiency Perovskite Quantum Dot Hybrid Nonfullerene Organic Solar Cells with Near‐Zero Driving Force

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Ligand-assisted cation-exchange engineering for high-efficiency colloidal Cs1−xFAxPbI3 quantum dot solar cells with reduced phase segregation

Cited by 489 publications

References 48 publications

Surface Termination of CsPbBr3 Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy

Surface Termination of CsPbBr3 Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy

Lead Halide Perovskite Nanocrystals: Room Temperature Syntheses toward Commercial Viability

High‐Efficiency Perovskite Quantum Dot Hybrid Nonfullerene Organic Solar Cells with Near‐Zero Driving Force

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Product

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Surface Termination of CsPbBr₃ Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy

Surface Termination of CsPbBr₃ Perovskite Quantum Dots Determined by Solid-State NMR Spectroscopy