Tunable blue-shift of the charge-transfer photoluminescence in tetrapod-shaped CdTe/CdSe nanocrystals

Golinskaya, A. D.; Смирнов, А.М.; Kozlova, Maria V.; Zharkova, E. V.; Vasiliev, R. B.; Манцевич, В. Н.; Днепровский, В. С.

doi:10.1016/j.rinp.2021.104488

Cited by 13 publications

(8 citation statements)

References 53 publications

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“…Early experimental studies in type-II quantum dot core/shell nanocrystals reported significant blue-shifts (20−200 meV) of the photoluminescence peak when switching from single excitons to multiexcitons or charged excitons. 15,23−25 Similar findings have been reported in other type-II and quasi-type-II heterostructures, such as nanorods, 1 tetrapods, 26 dot-in-rods, 27 and rod-in-rods. 28 The origin of these shifts is connected with the Coulomb interactions between the recombining exciton and the spectator charges.…”

Section: ■ Introductionsupporting

confidence: 64%

Highly Charged Excitons and Biexcitons in Type-II Core/Crown Colloidal Nanoplatelets

Llusar

Climente

2022

J. Phys. Chem. C

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The optoelectronic properties of type-II CdSe/ CdTe colloidal nanoplatelets (NPLs) charged with neutral excitons (X 0 ) have been intensively investigated in the last years. Motivated by the recent experimental progress, here we use effective mass simulations to study the effect of charging core/ crown NPLs with a few extra electrons or holes. Emission spectra are calculated for charged excitons (X n , with n = 2 to n = −3) and biexcitons (XX). The strong Coulomb interactions within the platelet lead to a number of remarkable properties. For excitons, varying the number of excess charges gives rise to band gap redand blue-shifts spanning over 100 meV and widely tunable oscillator strength. For biexcitons, the binding energy can be tuned from nearly nonbonding to strongly antibonding (∼40 meV) by modulating the core/crown area ratio. We conclude that the number of excess carriers injected into type-II NPLs is a versatile degree of freedom to modulate the optoelectronic properties.

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Section: ■ Introductionsupporting

confidence: 64%

Highly Charged Excitons and Biexcitons in Type-II Core/Crown Colloidal Nanoplatelets

Llusar

Climente

2022

J. Phys. Chem. C

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“…The combination of covalent bonds and electronegative atoms is the main combination mode of hydrogen atoms. We observe that the absorption peak position of 5.60 THz calculated by theory is not reflected in the spectrum detected by experiment, which may be connected to temperature through analysis [ 36 ]. In molecular systems, hydrogen bonds are easily impinged by temperature, which further leads to molecular vibration frequency become different, thus leading to the frequency shift of peak position [ 37 ].…”

Section: Resultsmentioning

confidence: 99%

Moxa Wool in Different Purities and Different Growing Years Measured by Terahertz Spectroscopy

et al. 2022

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Moxa wool is a traditional Chinese herbal medicine, which can warm channels to dispel coldness. At present, there is no unified index to evaluate the purity and growing years of moxa wool in the market. Terpineol is one of the effective substances in the volatile oil of moxa wool. Here, we characterize the purity and growing years of moxa wool by studying terpineol. Gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC) are the methods for monitoring terpineol at present, all of which have defects of complicated procedures. We established linear fitting to distinguish the different purities of moxa wool through the intensities (areas) of terpineol, the characteristic peaks, and the consequence presented; the coefficient of determination (R2) was higher than 0.90. Furthermore, based on the characteristic peak position of standard terpineol, the correlation model with the purity and growing year of moxa wool was set up, thereby differentiating the quality of moxa wool. We have built the partial least squares (PLS) model of the growing years of moxa wool with high accuracy, and the determination coefficient is greater than 0.98. In addition, we compare the quantitative accuracy of Raman spectroscopy with terahertz technology. Finally, a new method of terahertz spectroscopy to evaluate quality of moxa wool was found. It provides a new idea for the identification of inferior moxa wool in the market and a new method for identifying the quality of moxa wool in traditional Chinese medicine.

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“…Semiconductor nanocrystals (NCs) have held center stage for more than two decades by virtue of their unique optical and electrical properties, which open up the scope of their application in a plethora of fields. − These properties can be tuned by playing around with parameters like chemical composition, ligand coating, size, and shape. − NCs of exotic, non-spherical shape, like nanotetrapods (NTPs), are attractive by virtue of their scope in the field of inorganic dendrimers and in optoelectronics. − There has been significant advance in the control of the size and morphology of semiconductor NTPs through synthetic protocols. ,,, The major roadblock in devising applications of NTPs is their miniscule photoluminescence (PL) quantum yield (ϕ PL ), attributed to a large number of defect states that trap the charge carriers. The abundance of such traps is due to the large surface area of the arms of the NTPs. , The arms of the NTPs contribute to the enhancement of ϕ PL , suppressing their blinking .…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Enhancement of Stokes Shifted Photoluminescence Quantum Yield and Lifetime from Ag(I)-Doped CdSe Nanotetrapods: Implications for Optoelectronic and Photonic Devices

Ali

Das

Bhandari

et al. 2023

ACS Appl. Nano Mater.

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Ag(I)-doped CdSe nanotetrapods (NTPs) have been prepared using the post-synthesis cation exchange method. The shape and crystal structure of NTPs are found to be conserved after doping. The photoluminescence (PL) spectrum is Stokes shifted by 110 nm (0.33 eV) in doped NTPs at the highest dopant content (0.6%). The PL quantum yield increases to 11% from a value of 1.6% in undoped NTPs, with the emergence of a new, significantly longer component with a lifetime of 143 ns, at the cost of the fastest, nanosecond or lower component in the undoped NTPs. The dynamics of hole capture, which is the primary photoprocess that brings about the PL enhancement, has been elucidated by ultrafast transient absorption spectroscopy. Hence, Ag-doped colloidal three-dimensional NTPs are shown to be promising photoluminescent materials, which are less likely to suffer from the issue of the reabsorption of emitted photons due to the large Stokes shift emission. There are immense possibilities for their application in colloidal nanocrystal-based optoelectronic and photonic devices like light-emitting diodes and luminescent solar concentrators.

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Tunable blue-shift of the charge-transfer photoluminescence in tetrapod-shaped CdTe/CdSe nanocrystals

Cited by 13 publications

References 53 publications

Highly Charged Excitons and Biexcitons in Type-II Core/Crown Colloidal Nanoplatelets

Highly Charged Excitons and Biexcitons in Type-II Core/Crown Colloidal Nanoplatelets

Moxa Wool in Different Purities and Different Growing Years Measured by Terahertz Spectroscopy

Mechanism of Enhancement of Stokes Shifted Photoluminescence Quantum Yield and Lifetime from Ag(I)-Doped CdSe Nanotetrapods: Implications for Optoelectronic and Photonic Devices

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