Optical Properties of CdS Nanocrystals Doped with Zinc and Copper

Nitsuk, Yu. A.; Kiose, M. I.; Vaksman, Yu. F.; Smyntyna, V.; Yatsunskyi, I. R.

doi:10.1134/s1063782619030138

Cited by 6 publications

(2 citation statements)

References 10 publications

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“…Розмір наночастинок оцінювали за зсувом краю фундаментального поглинання в наближенні ефективних мас (табл.1) за формулою Вонга [3].…”

Section: методика експериментуunclassified

Nature of Zinc Oxide Colloidal Nanocrystals Photoluminescence

Nitsuk,

Huseynova,

Mamoilenko

et al. 2023

SEMST

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The purpose of the study is to determine the nature of the radiative transitions responsible for the visible radiation of zinc oxide nanocrystals. Show that the size of nanocrystallites does not affect the spectral composition and location of long-wave luminescence. ZnO nanocrystals obtained by the method of colloidal synthesis with or without gelatin stabilization were investigated in the paper. The size of the nanocrystallites was determined in the approximation of the effective masses by the magnitude of the fundamental absorption edge shift. The results of calculating the size of nanocrystallites agree well with the results of SEM studies. It is shown that the main factor affecting the size of nanocrystallites is the concentration of precursors. Photoluminescence spectra of colloidal ZnO nanocrystals were studied in two spectral regions – ultraviolet and visible. Photoluminescence spectra in the ultraviolet region are characterized by three emission lines, the location of which depends on the concentration of precursors, that is, on the width of the band gap. Analysis of the energy states of intrinsic defects in nanostructured zinc oxide showed that the first two emission lines are associated with radiative transitions of excitons bound on neutral interstitial zinc atoms and on neutral zinc vacancies. The third line of ultraviolet radiation is caused by radiative transitions with the participation of deep donors, which are interstitial zinc atoms in the +2 charge state. The visible radiation spectra of colloidal ZnO nanocrystals are characterized by broad non-elemental emission bands in the blue-green and yellow-red regions of the spectrum. A detailed analysis of the spectra at different concentrations of precursors showed that the change in concentrations of precursors does not affect the spectral location of elementary emission lines. The absence of impurity absorption lines indicates that the centers responsible for visible radiation are donor-acceptor pairs. The analysis of the ratio of the emission lines intensities with increasing concentrations of the precursors shows that interstitial zinc and oxygen atoms dominate in the studied nanocrystals at high concentrations. As a result, in samples with a high concentration of precursors, blue radiation dominates over yellow and green. Thus, the study shows that by changing the concentrations of precursors, it is possible to influence both the spectral location of the edge ultraviolet luminescence and the intensity of individual long-wave luminescence components. The resulting colloidal ZnO nanocrystals can be used as luminescent sensors.

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Section: методика експериментуunclassified

Nature of Zinc Oxide Colloidal Nanocrystals Photoluminescence

Nitsuk,

Huseynova,

Mamoilenko

et al. 2023

SEMST

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“…Оптичні характеристики досліджуваних зразків підтверджують факт нарощування шару ZnS на КТ CdS. В спектрі поглинання (рис.2) спостерігається червоне зміщення для наноструктур CdS / ZnS в порівнянні з КТ ядра CdS, що вказує на формування структури CdS / ZnS, а не на утворення твердого розчину Cd x Zn 1-x S 1-y , як це спостерігалося в роботі [14]. В останньому випадку спектр поглинання був би зміщений в більш короткохвильову область у порівнянні зі спектром вихідних структур через більшу енергію забороненої зони твердого розчину Cd x Zn 1-x S 1-y .…”

Section: рис 1 спектри фотолюмінесценції кт Cds і наноструктури Cds / Znsunclassified

INCREASING THE PHOTOLUMINESCENCE EFFICIENCY OF CdS NC GROWN IN A GELATINOUS ENVIRONMENT

Skobeeva¹,

Smyntyna²,

Kiose³

et al. 2021

SEMST

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The optical and luminescent properties of nanostructures of CdS / ZnS QDs and CdS QDs doped with lithium, obtained by the sol-gel technology in an aqueous solution of gelatin, have been studied. It was determined from the optical absorption spectra of the CdS / ZnS QD nanostructures that the thickness of the shell layer corresponds to the thickness of one ZnS monolayer. The luminescence spectra revealed a significant increase in the intensity of luminescence nanostructure. The absorption spectra of undoped and doped CdS NCs coincide, which indicates that there is no change in the NC size and the absence of the formation of a lithium-sulfur compound. The luminescence spectra of lithium-doped QDs demonstrate an increase in the luminescence intensity, which is associated with the passivation of surface states.

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