Recent Advances in Ligand Design and Engineering in Lead Halide Perovskite Nanocrystals

Hills‐Kimball, Katie; Yang, Hanjun; Cai, Tong; Wang, Junyu; Chen, Ou

doi:10.1002/advs.202100214

Cited by 141 publications

(105 citation statements)

References 470 publications

(1,358 reference statements)

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“…[75] To unveil the binding nature of surface ligands and visualize their dissociation from the PQD surface, a number of spectroscopic techniques have been implemented to analyze the surface structure, which include nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). [30,70,74,76] Among those, NMR is an indispensable tool to analyze the organic-inorganic QD-ligand interface and unravelling the binding motifs accordingly. In the NMR spectra of PQDs, surface-bound ligands with featured broadened spectral lines can be easily distinguished from non-binding compounds showing narrow resonances.…”

Section: Surface Structure and Characterizationmentioning

confidence: 99%

Surface Chemistry Engineering of Perovskite Quantum Dots: Strategies, Applications, and Perspectives

et al. 2021

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The presence of surface ligands not only plays a key role in keeping the colloidal integrity and non‐defective surface of metal halide perovskite quantum dots (PQDs), but also serves as a knob to tune their optoelectronic properties for a variety of exciting applications including solar cells and light‐emitting diodes. However, these indispensable surface ligands may also deteriorate the stability and key properties of PQDs due to their highly dynamic binding and insulating nature. To address these issues, a number of innovative surface chemistry engineering approaches have been developed in the past few years. Based on an in‐depth fundamental understanding of the surface atomistic structure and surface defect formation mechanism in the tiny nanoparticles, a critical overview focusing on the surface chemistry engineering of PQDs including advanced colloidal synthesis, in‐situ surface passivation, and solution‐phase/solid‐state ligand exchange is presented, after which their unprecedented achievements in photovoltaics and other optoelectronics are presented. The practical hurdles and future directions are critically discussed to inspire more rational design of PQD surface chemistry toward practical applications.

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Section: Surface Structure and Characterizationmentioning

confidence: 99%

Surface Chemistry Engineering of Perovskite Quantum Dots: Strategies, Applications, and Perspectives

et al. 2021

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“…Figure E presents a TEM image of ZnS nanowires, where each nanowire is characterized with a length of 10 nm and diameter of 1.7 nm. The inset displays an illustration of ZnS nanowires separated by 1 nm length, compatible with the interdigitated arrangement of the octylamine ligands Figure F depicts a XRD pattern with reflections as labeled on the panel, in agreement with a wurtzite structure.…”

Section: Results and Discussionmentioning

confidence: 80%

“…The inset displays an illustration of ZnS nanowires separated by 1 nm length, compatible with the interdigitated arrangement of the octylamine ligands. 32 Figure 1F depicts a XRD pattern with reflections as labeled on the panel, in agreement with a wurtzite structure. Raman measurements (Figure S2) confirm the wurtzite phase too.…”

Section: ■ Results and Discussionmentioning

confidence: 83%

Room Temperature Colloidal Coating of II–VI Nanoplatelets with Quantum Dots

2021

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The low-temperature colloidal production of II−VI nanoplatelet heterostructures has stimulated the interest of researchers due to the possible uses of these materials in various optoelectronic devices. Here, we report a roomtemperature coating by CdS or ZnS dots of preprepared CdSe nanoplatelets. The dot coating process made use of a synthesis developed for the formation of freestanding CdS and ZnS species, involving injection of a metal precursor into reactive sulfur−amine solutions at room temperature. CdSe structured nanoplatelets with 1.75 nm thickness were used as the core constituent. The structural properties were investigated using Fourier transform infrared spectroscopy and advanced electron microscopy, while the elemental mapping was verified using high-angle annular dark field transmission electron microscopy. The results showed a dots-on-plate structure, resembling an intermediate configuration between core/crown or core/shell heterostructures. A thorough study of optical properties demonstrated a dramatic spectral shift of the absorption edge to lower energies, regardless of the uniformity of the coating layer, maintaining spectral stability over two months while stored at ambient conditions. Other optical measurements included examination of temperature-dependent photoluminescence and transient photoluminescence decay, from room temperature down to ∼4 K. These measurements revealed excitons, trions, and trapped carrier recombination emission with variable relative intensities following the temperature change. The dots-on-plate structures studied displayed a short photoluminescence decay (≤nanosecond), compatible with that of core/shell (crown) structures prepared at high temperatures. As a result, the presented techniques are alternative pathways that eliminate the requirement for excessive temperatures and/or multistep processes, instead providing rapid, inexpensive, and scalable procedures with practical advantages.

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“…[ 276 ] On the other hand, colloidal perovskite NPls contain well‐defined ligands on the surface, in which charge transport properties can be controlled by tuning the length of the ligands without compromising on the size of the NPls. [ 24,277–279 ]…”

Section: Colloidal Perovskite Nanoplatelet Light‐emitting Diodesmentioning

confidence: 99%

Colloidal Metal‐Halide Perovskite Nanoplatelets: Thickness‐Controlled Synthesis, Properties, and Application in Light‐Emitting Diodes

et al. 2022

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Colloidal metal‐halide perovskite nanocrystals (MHP NCs) are gaining significant attention for a wide range of optoelectronics applications owing to their exciting properties, such as defect tolerance, near‐unity photoluminescence quantum yield, and tunable emission across the entire visible wavelength range. Although the optical properties of MHP NCs are easily tunable through their halide composition, they suffer from light‐induced halide phase segregation that limits their use in devices. However, MHPs can be synthesized in the form of colloidal nanoplatelets (NPls) with monolayer (ML)‐level thickness control, exhibiting strong quantum confinement effects, and thus enabling tunable emission across the entire visible wavelength range by controlling the thickness of bromide or iodide‐based lead‐halide perovskite NPls. In addition, the NPls exhibit narrow emission peaks, have high exciton binding energies, and a higher fraction of radiative recombination compared to their bulk counterparts, making them ideal candidates for applications in light‐emitting diodes (LEDs). This review discusses the state‐of‐the‐art in colloidal MHP NPls: synthetic routes, thickness‐controlled synthesis of both organic–inorganic hybrid and all‐inorganic MHP NPls, their linear and nonlinear optical properties (including charge‐carrier dynamics), and their performance in LEDs. Furthermore, the challenges associated with their thickness‐controlled synthesis, environmental and thermal stability, and their application in making efficient LEDs are discussed.

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Recent Advances in Ligand Design and Engineering in Lead Halide Perovskite Nanocrystals

Cited by 141 publications

References 470 publications

Surface Chemistry Engineering of Perovskite Quantum Dots: Strategies, Applications, and Perspectives

Surface Chemistry Engineering of Perovskite Quantum Dots: Strategies, Applications, and Perspectives

Room Temperature Colloidal Coating of II–VI Nanoplatelets with Quantum Dots

Colloidal Metal‐Halide Perovskite Nanoplatelets: Thickness‐Controlled Synthesis, Properties, and Application in Light‐Emitting Diodes

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