Methods for the ICP-OES Analysis of Semiconductor Materials

Morrison, Calynn; Sun, Haochen; Yao, Yue; Loomis, Richard A.; Buhro, William E.

doi:10.1021/acs.chemmater.0c00255

Cited by 42 publications

(43 citation statements)

References 35 publications

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“…The composition of the NPLs synthesized was determined using ICP-OES analysis according to the procedure outlined in ref. 47. Interestingly, the Se/(Se+S) ratio in the NPLs is essentially the same as the feed ratio, which is different from previous reports [36][37][38] and is in good agreement with the reaction mechanism involving fast and complete conversion of chalcogen precursors at the nucleation stage.…”

Section: Resultscontrasting

confidence: 60%

CdSexS1-x Alloyed Nanoplatelets with Continuously Tunable Blue-Green Emission

Antanovich

Yang

Erwin

et al. 2022

Preprint

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Cadmium chalcogenide nanoplatelets (NPLs) are established as promising materials for a wide variety of optoelectronic applications due to their properties surpassing in many aspects counterpart nanocrystals (NCs) with other shapes. Most of these features arise from strong quantum confinement in the direction of thickness which can be tuned with precision down to one monolayer. However, atomic smoothness of their basal planes and hence the ability to change the NPL thickness only in discrete steps prevent precise tuning of absorption and photoluminescence spectra unlike in the case of quantum dots. Preparation of alloyed NCs provides a potential solution to this problem, but it is complicated by the different reactivity of chalcogenide sources, which becomes even more restrictive in the case of NPLs, since they are more sensitive to alterations of reaction conditions. In this work, we overcome this obstacle by employing highly reactive stearoyl sulfide and selenide as chalcogen sources, which enable straightforward variation of the NPLs composition and thickness by changing the ratio of chalcogen precursors and reaction temperature, respectively. Alloyed CdSexS1-x NPLs obtained exhibit tunable absorption and photoluminescence bands covering the blue-green region from 380 to 520 nm with bright band-edge emission and quantum yields of ~30–50 % due to their relatively small lateral size enabled by a much finer control of the lateral growth.

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Section: Resultscontrasting

confidence: 60%

CdSexS1-x Alloyed Nanoplatelets with Continuously Tunable Blue-Green Emission

Antanovich

Yang

Erwin

et al. 2022

Preprint

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“…While these techniques are typically employed to reveal the core stoichiometry, the use of ICP-based techniques to quantify the reaction products of chemical probes or dopants can inform on the native surface structure and its reactivity. For example, both ICP-OES and ICP-MS can distinguish between cationic dopants incorporated at the surface or within the core lattice. , Additionally, the stoichiometry of surface moieties (e.g., Z-type ligands) liberated by ligand-based probes can be assessed by measuring the metal ion concentration using ICP-based techniques in tandem with 1 H NMR spectroscopy to quantify the organic constituents . Because the detection limits for certain elements can be orders of magnitude higher when using ICP-OES than for ICP-MS, selection of the proper detection and sample digestion methods for each element is crucial to obtain trustworthy, highly quantitative data …”

Section: Studying Nanocrystal Surfaces With a Molecular-level Approachmentioning

confidence: 99%

“…21 Because the detection limits for certain elements can be orders of magnitude higher when using ICP-OES than for ICP-MS, selection of the proper detection and sample digestion methods for each element is crucial to obtain trustworthy, highly quantitative data. 78 Finally, the computational tool density functional theory (DFT) is an important and increasingly common approach to studying the physical structure of the NC surface on a molecular level. For example, studies rationalizing the presence of hydroxide ligands on PbS NCs, 80 preferred ligand packing arrangements, 81 differences in binding strengths of Z-type ligands on specific NC surface facets and sites, 36,82 and dimerization of surface atoms as a source of electronic traps 32,83 have provided immense structural insights.…”

Section: T H Imentioning

confidence: 99%

Molecular-Level Insight into Semiconductor Nanocrystal Surfaces

2021

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Semiconductor nanocrystals exhibit attractive photophysical properties for use in a variety of applications. Advancing the efficiency of nanocrystal-based devices requires a deep understanding of the physical defects and electronic states that trap charge carriers. Many of these states reside at the nanocrystal surface, which acts as an interface between the semiconductor lattice and the molecular capping ligands. While a detailed structural and electronic understanding of the surface is required to optimize nanocrystal properties, these materials are at a technical disadvantage: unlike molecular structures, semiconductor nanocrystals lack a specific chemical formula and generally must be characterized as heterogeneous ensembles. Therefore, in order for the field to improve current nanocrystal-based technologies, a creative approach to gaining a “molecular-level” picture of nanocrystal surfaces is required. To this end, an expansive toolbox of experimental and computational techniques has emerged in recent years. In this Perspective, we critically evaluate the insight into surface structure and reactivity that can be gained from each of these techniques and demonstrate how their strategic combination is already advancing our molecular-level understanding of nanocrystal surface chemistry.

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“…The QDs were prepared for elemental analysis using a digestion process modified from a previously published method. 36…”

Section: Synthesis Of Znsementioning

confidence: 99%

“…It was noted that pre-oxidizing the samples with hydrogen peroxide (H2O2), can mitigate the formation of volatile compounds upon the addition of a strong acid. 36 The same approach was used here to digest the ZnSe size series, whereby each QD sample was first oxidized using H2O2 prior to digestion with nitric acid.…”

mentioning

confidence: 99%

ZnSe Quantum Dots: Determination of Molar Extinction Coefficient for UV to Blue Emitters

Toufanian¹,

Zhong²,

Kays³

et al. 2020

Preprint

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<p>The focus on heavy metal-free visible emitters in optoelectronic devices has increased interest in ZnSe semiconductor quantum dots (QDs) over the past decade. Empirical fit equations correlating the lowest energy electron transition to their size and molar extinction coefficients (ε) are often used to determine the concentration of suspensions containing QDs. This is essential to the design and successful synthesis of complex semiconductor nanoparticles including core/shell and dot-in-rod heterostructures as well as consistent device fabrication. While these equations are known and heavily used for CdSe, CdTe, CdS, PbS, etc., they are not well established for ZnSe nanocrystals; the only two reports of ε in the literature differ by over an order of magnitude. In this study, a series of ZnSe QDs with diameters ranging from 2 to 6 nm were characterized with small angle X-ray scattering (SAXS), transmission electron microscopy (TEM), and UV-Vis spectroscopy. SAXS-based size analysis enabled practical inclusion of small particles in the evaluation. Elemental analysis with microwave plasma atomic emission spectroscopy (MP-AES) yields a non-stoichiometric Zn:Se ratio consistent with zinc-terminated spherical ZnSe QDs. Using these combined results, molar extinction coefficients for each QD sample were calculated. Empirical fit equations correlating QD size with its lowest energy electron transition (i.e., 1S peak position) and molar extinction coefficients for both 1S peak and high energy wavelengths are reported. These results will enable the consistent and reliable use of ZnSe core particles in complex heterostructures and devices.</p>

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Methods for the ICP-OES Analysis of Semiconductor Materials

Cited by 42 publications

References 35 publications

CdSexS1-x Alloyed Nanoplatelets with Continuously Tunable Blue-Green Emission

CdSexS1-x Alloyed Nanoplatelets with Continuously Tunable Blue-Green Emission

Molecular-Level Insight into Semiconductor Nanocrystal Surfaces

ZnSe Quantum Dots: Determination of Molar Extinction Coefficient for UV to Blue Emitters

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