Electron energy level engineering in Zn<sub>1−x</sub>Cd<sub>x</sub>Se nanocrystals

Sonawane, Kiran G.; Phadnis, Chinmay; Tatikondewar, Laxman; Sudarsan, V.; Kshirsagar, Anjali; Mahamuni, Shailaja

doi:10.1039/c4tc01555j

Cited by 9 publications

(7 citation statements)

References 46 publications

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“…The only trap levels available are the ones at the surface of the NCs. Low-temperature PL spectroscopy further reveals the minimal interfacial defects . Moreover, in graded core–shell NCs, the electron and hole are localized in the central region, resulting in minimized trap-assisted blinking.…”

Section: Resultsmentioning

confidence: 99%

“…Low-temperature PL spectroscopy further reveals the minimal interfacial defects. 15 Moreover, in graded core−shell NCs, the electron and hole are localized in the central region, resulting in minimized trap-assisted blinking. On the other hand, for Alloy-36, there is a substantial overlap of electron and hole wave function making the same susceptible to Auger recombination, as well as trap-assisted blinking.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Graded and alloyed NCs are synthesized by the wet chemical method, synthesis and structural details are reported earlier. , In brief, Zn and Cd precursors were mixed in noncoordinating solvent, and the Se precursor was injected at elevated temperature (300 °C). Due to the different reactivity of Cd and Zn precursors, structures with CdSe-rich core and ZnSe-rich shell, with radially graded composition from core to shell, are formed.…”

Section: Methodsmentioning

confidence: 99%

“…Radial change in confinement potential will have an effect on the localization of charge carriers and hence on the optical properties of the NCs. Manifestations of diverse microscopic composition and hence dissimilar confinement potential shape are being looked at from various angles. − It can be ideally revealed at a single NC level. Semiconductor NCs, at individual level, show random fluctuations in photoluminescence (PL) emission intensity with time, on continuous excitation, a phenomenon commonly referred to as PL intermittency or “blinking”.…”

Section: Introductionmentioning

confidence: 99%

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Manifestations of Varying Grading Level in CdSe/ZnSe Core–Shell Nanocrystals

et al. 2016

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Graded interface core–shell nanocrystals (NCs) are being investigated to attain highly luminescent systems and are also anticipated to be “blinking-free” at the single-particle level. In the present work, CdSe/ZnSe-graded core–shell NCs with varying confinement potential profile are studied at the single-particle level. The internal structure of NCs is determined with the aid of optical, structural, and chemical probes. Notably, the radiative lifetime for different nanostructures decays monoexponentially. The variation in the radiative lifetime due to differing internal structure is understood on the basis of recently reported first-principles study on different interfaces of core–shell NCs, in particular attributed to varying overlap of electron–hole wave functions. The single NC measurements reveal that the percentage of nonblinking NCs is higher for slowly varying confinement potential. Statistically suppressed blinking (∼80%) and a single exponential PL decay curve, accompanied by a very narrow (∼30 meV) emission line at the single NC level, are observed in graded CdSe/ZnSe core–shell NCs.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Manifestations of Varying Grading Level in CdSe/ZnSe Core–Shell Nanocrystals

et al. 2016

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“…323,324 Most research on bismuth selenide has focused on its rhombohedral topological insulator phase, 325 as the 1.25 eV orthorhombic phase has only recently been isolated in a single-phase. 326 The use of chemical deposition techniques to produce bismuth sulfide has seen considerable interest since, [327][328][329] as offering a low temperature, facile synthesis is highly desirable for device manufacture, although the quality and crystallinity of films may suffer compared to evaporation techniques. 330,331 Nevertheless, chemically deposited thin films of Bi 2 S 3 have been used in combination with lead chalcogenides to produce cells of 0.5% efficiency in 2011, 332 and 2.5% in 2013.…”

Section: Bismuth Sulfidementioning

confidence: 99%

Beyond methylammonium lead iodide: prospects for the emergent field of ns²containing solar absorbers

2017

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The field of photovoltaics is undergoing a surge of interest following the recent discovery of the lead hybrid perovskites as a remarkably efficient class of solar absorber. Of these, methylammonium lead iodide (MAPI) has garnered significant attention due to its record breaking efficiencies, however, there are growing concerns surrounding its long-term stability. Many of the excellent properties seen in hybrid perovskites are thought to derive from the 6s electronic configuration of lead, a configuration seen in a range of post-transition metal compounds. In this review we look beyond MAPI to other ns solar absorbers, with the aim of identifying those materials likely to achieve high efficiencies. The ideal properties essential to produce highly efficient solar cells are discussed and used as a framework to assess the broad range of compounds this field encompasses. Bringing together the lessons learned from this wide-ranging collection of materials will be essential as attention turns toward producing the next generation of solar absorbers.

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Probing Absolute Electronic Energy Levels in Hg‐Doped CdTe Semiconductor Nanocrystals by Electrochemistry and Density Functional Theory

et al. 2015

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The absolute electronic energy levels in Hg-doped CdTe semiconductor nanocrystals (CdHgTe NCs) with varying sizes/volumes and Hg contents are determined by using cyclic voltammetry (CV) measurements and density functional theory (DFT) -based calculations. The electrochemical measurements demonstrate several distinct characteristic features in the form of oxidation and reduction peaks in the voltammograms, where the peak positions are dependent on the volume of CdHgTe NCs as well as on their composition. The estimated absolute electronic energy levels for three different volumes, namely 22, 119 and 187 nm(3) with 2.7±0.3 % of Hg content, show strong volume dependence. The volume-dependent shift in the characteristic reduction and oxidation peak potential scan can be attributed to the alteration in the energetic band positions owing to the quantum confinement effect. Moreover, the composition (Cd/Hg=98.3/1.7 and 97.0/3.0) -dependent alteration in the electronic energy levels of CdHgTe NCs for two different samples with similar volumes (ca. 124±5 nm(3) ) are shown. Thus obtained electronic energy level values of CdHgTe NCs as a function of volume and composition demonstrate good congruence with the corresponding absorption and emission spectral data, as well as with DFT-based calculations. DFT calculations reveal that incorporation of Hg into CdTe NCs mostly affects the energy levels of conduction band edge, whereas the valence band edge remains almost unaltered.

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Electron energy level engineering in Zn_1−xCd_xSe nanocrystals

Abstract: Variation in composition provides an additional degree of freedom in nanocrystals design.

Cited by 9 publications

References 46 publications

Manifestations of Varying Grading Level in CdSe/ZnSe Core–Shell Nanocrystals

Manifestations of Varying Grading Level in CdSe/ZnSe Core–Shell Nanocrystals

Beyond methylammonium lead iodide: prospects for the emergent field of ns²containing solar absorbers

Probing Absolute Electronic Energy Levels in Hg‐Doped CdTe Semiconductor Nanocrystals by Electrochemistry and Density Functional Theory

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Electron energy level engineering in Zn1−xCdxSe nanocrystals

Abstract: Variation in composition provides an additional degree of freedom in nanocrystals design.

Cited by 9 publications

References 46 publications

Manifestations of Varying Grading Level in CdSe/ZnSe Core–Shell Nanocrystals

Manifestations of Varying Grading Level in CdSe/ZnSe Core–Shell Nanocrystals

Beyond methylammonium lead iodide: prospects for the emergent field of ns2containing solar absorbers

Probing Absolute Electronic Energy Levels in Hg‐Doped CdTe Semiconductor Nanocrystals by Electrochemistry and Density Functional Theory

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Product

Resources

About

Electron energy level engineering in Zn_1−xCd_xSe nanocrystals

Beyond methylammonium lead iodide: prospects for the emergent field of ns²containing solar absorbers