Interface polarization in heterovalent core–shell nanocrystals

materials because of their high color purity, large-scale solution processability, and tunable electrical and optical properties. [1][2][3] The InP-based QDs have been synthesized with near-unity photoluminescence quantum yield (PL QY), which can meet the RoHS requirements by removing toxic Cd from QD emitters. [4,5] Despite recent advances in QD light-emitting diodes (QD-LEDs), including a 20% external quantum efficiency and enhanced device lifetime, [4,[6][7][8][9][10][11] multicolored and pixelated QD-LED devices still need to be developed. [12] The QDs are typically synthesized using wet chemistry, which is useful for large-scale solution processes. When QDs are incorporated into a device structure and sandwiched into a multilayered thin film, solvent orthogonality should be considered because the pre-coated QD layer can be damaged by the solvent in the top layers. This can be a serious issue when the QD film is patterned as a pixelated display, where conventional photolithography cannot be used. [13,14] When photoresists are coated on top of the pre-existing QD film, the QD film is easily removed, or the two layers intermix. This is because QDs are easily dissolved or washed with organic solvents, which are also used to dissolve the photoresist. Thus, alternative patterning methods, such as inkjet [15][16][17][18][19] and transfer printing, [20][21][22] have been employed to form multicolor QD patterns. However, inkjet printing has a limited tact time and suffers from nozzle clogging issues for industrial applications. [15,23] In addition, transfer printing can yield high-resolution patterns, but the process requires precise control of kinetic parameters, such as pick-up and peeling speed, which limits the reproducibility of the process. [21,22] Therefore, it is highly desirable to use conventional photolithography for patterning QD films. [24] Two methods have been suggested for employing photolithography to QD film patterning. One is the addition of light-sensitive cross-linking molecules to the QD solution. The molecule can either replace the original ligands or can be included as an additional substance. [25][26][27] Upon light exposure, the molecules form a crosslinked structure between the QDs, and the patterns can be formed by solvent dipping. The other method directly uses a conventional photoresist because it is a well-designed chemical that provides high resolution and etch-resistance. Owing to the absence of solvent resistance in QD films, the lift-off method Colloidal quantum dot-based light-emitting diodes (QD-LEDs) are one of the potential future self-emissive displays owing to their large-scale solutionprocessibility and high color purity. For the industrial application of QD-LEDs, high-performance QD-LED and high-resolution patterning of quantum dot (QD) films are required. Photolithography is an ideal tool for patterning QD films. Previously, the high-resolution patterning of QD films using direct photolithography by ultra-thin atomic layer deposition of ZnO on the QD surface is reported. Th...

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“…[ 33 ] The red – and green‐emitting InP/ZnSe/ZnS QDs were prepared as described by Hahm et al. [ 34,35 ]…”

Section: Methodsmentioning

confidence: 99%

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

Lee

Kim

Han

et al. 2022

Adv Materials Inter

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“…In addition, Bae et al. [ 50 ] reported that the interface polarization produced by III–VI bond, would increase the optical bandgap but without detailed element analysis, which might be part of the origin for the blue‐shift of the emission wavelength.…”

Section: Resultsmentioning

confidence: 99%

“…These two results confirm the fact that much anion exchange results in the smaller size of InP core, therefore the blue-shift of emission wavelength under I − -rich environment. In addition, Bae et al [50] reported that the interface polarization produced by III-VI bond, would increase the optical bandgap but without detailed element analysis, which might be part of the origin for the blue-shift of the emission wavelength.…”

Section: H Nuclear Magnetic Resonance (Nmr) Measurements Tomentioning

confidence: 99%

Synergistic Effect of Halogen Ions and Shelling Temperature on Anion Exchange Induced Interfacial Restructuring for Highly Efficient Blue Emissive InP/ZnS Quantum Dots

Cui

Mei

Wen

et al. 2022

Small

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biocompatibility, and excellent optoelectronic properties such as convenient emission tunability, high stability, and color purity. Among them, cadmiumbased (Cd-based) [1,2] and lead-based (Pb-based) [5,11] QDs have been studied a lot and much progress has been obtained over the past few decades. However, their toxicity limits further application in many fields. Indium phosphide (InP) QDs with wide emission range and no toxicity are promising alternative emitting material, rapidly acquiring extensive research, but it is still a great challenge to obtain highquality InP QDs. [15][16][17][18] To date, considerable research has focused on growth kinetics and synthetic strategies of InP QDs. [19][20][21][22][23][24][25] Apart from the common method where indium acetate and tris(trimethylsilyl)phosphine ((TMS) 3 P) are utilized, indium halide is widely employed in the preparation of InP/ ZnS QDs combining with zinc halide and amino phosphine recently owing to its low cost and safety. As has been reported, halide plays a critical role in its nucleation and surface chemistry. Hens et al. [26] reported the synthesis of InP/ZnS QDs with green and red emission tuning by halogen ions owing to their different steric hindrance effects. Considering the slow surface reaction rates of iodideThe ORCID identification number(s) for the author(s) of this article can be found under

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“…Core-shell nanoparticles (CS-NPs) are attracting significant interest in chemistry and material science, and are widely used in many applications such as catalysis, optics, electronics, and biomedical applications due to their novel optical, magnetic and electronic characteristics [1][2][3][4][5][6] . The unique and versatile functionalities of CS-NPs arise from the physical and chemical properties of both the core and the shell 7,8 , determined by the three-dimensional (3D) arrangement of the atoms, particularly at the core-shell interfaces.…”

Section: Introductionmentioning

confidence: 99%

Probing the atomically diffuse interfaces in core-shell nanoparticles in three dimensions

Xie

Zhang

et al. 2022

Preprint

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Deciphering the three-dimensional atomic structure of solid-solid interfaces in core-shell nanomaterials is the key to understand their remarkable catalytical, optical and electronic properties. Here, we probe the three-dimensional atomic structures of palladium-platinum core-shell nanoparticles at the single-atom level using atomic resolution electron tomography. We successfully quantify the rich structural variety of core-shell nanoparticles including bond length, coordination number, local bond orientation order, grain boundary, and five-fold symmetry, all in 3D at atomic resolution. Instead of forming an atomically-sharp boundary, the core-shell interface is atomically diffuse with an average thickness of 4.2 Å, irrespective of the particle’s size, morphology, or crystallographic texture. The high concentration of Pd in the interface is highly related to the electric double layers of the Pd seeds. These results advance our understanding of core-shell structures at the fundamental level, providing potential strategies into nanomaterial manipulation and chemical property regulation.

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Interface polarization in heterovalent core–shell nanocrystals

Cited by 65 publications

References 45 publications

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

Nondestructive Direct Photolithography for Patterning Quantum Dot Films by Atomic Layer Deposition of ZnO

Synergistic Effect of Halogen Ions and Shelling Temperature on Anion Exchange Induced Interfacial Restructuring for Highly Efficient Blue Emissive InP/ZnS Quantum Dots

Probing the atomically diffuse interfaces in core-shell nanoparticles in three dimensions

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