Size and temperature dependence of the photoluminescence properties of NIR emitting ternary alloyed mercury cadmium telluride quantum dots

Jagtap, Amardeep; Chatterjee, Abhijit; Banerjee, Arup; Pendyala, Naresh Babu; Rao, K. S. R. Koteswara

doi:10.1088/0022-3727/49/13/135302

Cited by 10 publications

(6 citation statements)

References 55 publications

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“…The obtained temperature coefficient α is only slightly larger compared with the reported value for colloidal CdHgTe QDs with sizes from 2.5 to 4.2 nm, and the PL emission centered from 550 to 850 nm, respectively ((2.1−2.8) × 10 −4 eV•K −1 ). 32 The β value is in good agreement with the bulk value reported for CdTe (183 K). 33 To characterize the nonradiative relaxation processes occurring in CdHgTe QDs@NaCl powders, we analyzed the changes of their PL intensity upon increasing temperature (Figure 3c).…”

Section: ■ Results and Discussionsupporting

confidence: 86%

“…The values of these parameters extracted for CdHgTe QDs@NaCl are summarized in Table . The obtained temperature coefficient α is only slightly larger compared with the reported value for colloidal CdHgTe QDs with sizes from 2.5 to 4.2 nm, and the PL emission centered from 550 to 850 nm, respectively ((2.1–2.8) × 10 –4 eV·K –1 ) . The β value is in good agreement with the bulk value reported for CdTe (183 K) …”

Section: Resultssupporting

confidence: 83%

“…The extracted activation energy, E a , for CdHgTe QDs@NaCl is 91.6 meV (Table ). The activation energy previously reported for nonprotected CdHgTe QDs ( d QDs = 4.2 nm) emitting in the same region of the spectrum was 76.1 meV, suggesting favorable temperature stability of the emission properties of NaCl-protected CdHgTe QDs due to additional passivation by the NaCl matrix.…”

Section: Resultssupporting

confidence: 55%

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Sodium Chloride Protected CdHgTe Quantum Dot Based Solid-State Near-Infrared Luminophore for Light-Emitting Devices and Luminescence Thermometry

et al. 2017

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Solid-state luminophores operating in the near-infrared (NIR) region may have applications in sensing, communication, and medicine. We report environmentally protected solid-state NIR-emitting luminophores fabricated by embedding CdHgTe colloidal quantum dots (QDs) into a NaCl matrix, with remarkable photo-and thermal stability and a photoluminescence quantum yield of 31% in the solid state, which is among the highest reported for solid-state NIR luminophores so far. We employed this luminophore as a down-conversion layer in a NIR-light-emitting device with a stable emission at 940 nm. Carrier recombination dynamics of the CdHgTe QDs@NaCl powders are examined as a function of temperature using steady-state and transient photoluminescence spectroscopy, and characteristic parameters such as the band gap, the temperature coefficient, the Debye temperature, the activation energy of thermal quenching, and radiative and nonradiative recombination rates are derived. Temperature-dependent changes of the spectral position and the photoluminescence lifetime of CdHgTe QDs@NaCl are shown to serve as a base for two temperature detection schemes, namely, luminescence spectral and luminescence lifetime thermometry, a versatile optical technique for the noninvasive, noncontact estimation of local temperature.

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Section: ■ Results and Discussionsupporting

confidence: 86%

Section: Resultssupporting

confidence: 83%

Section: Resultssupporting

confidence: 55%

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Sodium Chloride Protected CdHgTe Quantum Dot Based Solid-State Near-Infrared Luminophore for Light-Emitting Devices and Luminescence Thermometry

et al. 2017

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“…In the Te 3d transition doublet, there are two chemically shifted peaks corresponding to the presence of Te(IV) oxide bonds. The dangling bonds of Te on the crystal surface are susceptible to oxidation and contribute to forming surface states [23]. ICP-MS measurements are employed to determine the atomic composition of the QDs, and the results are given in table 2.…”

Section: Optical and Structural Characterisationmentioning

confidence: 99%

“…The thermally activated process that is responsible for quenching of PL with temperature can be attributed to carrier trapping at the surface trap states [44]. A possible non-radiative recombination pathway is the dangling bonds at the nanocrystal surface due to unpassivated Te atoms [23]. In thioglycolicacid-capped CdTe QDs, it has been found that QDs with low luminescence contain a large fraction of surface Te atoms [50].…”

Section: Pl Intensitymentioning

confidence: 99%

Temperature- and size-dependent photoluminescence in colloidal CdTe and Cd _x Zn_1−xTe quantum dots

Balakrishnan¹,

Preethi²,

Sreeshma³

et al. 2021

J. Phys. D: Appl. Phys.

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Semiconductor colloidal quantum dots (QDs) of CdTe and alloyed Cd x Zn1−x Te QDs with N-acetyl-L-cysteine capping ligands are synthesized by a reflux method in aqueous solution. Alloying provides a new degree of freedom to tune the optical and electronic properties of the nanocrystals. The photoluminescence (PL) of Cd x Zn1−x Te QDs is sharper and displays a highly enhanced quantum yield (QY) of 65% relative to the 16% of CdTe QDs. The fluorescence of Cd x Zn1−x Te QDs is observed to be highly stable for over 12 months without degradation, while that of CdTe QDs begins to mildly flocculate around 8 months of storage. To characterise the material structure and composition, UV-Vis absorption spectroscopy, x-ray powder diffraction, transmission electron microscopy, and inductively coupled plasma mass spectrometry measurements are carried out. To understand the fundamental processes that play in the luminescence behaviour, temperature- and size-dependent PL spectra are investigated in the range 80–300 K. The Varshni and O’Donnell equations fit well on the PL peak emission energies and the Huang–Rhys parameter indicates the strengthening of exciton–phonon coupling in the nanocrystals upon alloying and with decreasing nanocrystal sizes. PL linewidth analysis reveals that the inhomogeneous broadening is considerably reduced in Cd x Zn1−x Te QDs relative to CdTe. Moreover, the quantum confinement effect of the nanocrystals leads to an increase in exciton–acoustic phonon interactions with the coefficients ranging between 26.9 and 95.6 µeV K−1 compared to the bulk CdTe value of 0.72 µeV K−1. Exciton–longitudinal optical phonon interactions are made stronger by the ZnTe alloying with the coefficients lying in the range between 24.8 and 41.7 meV and also with the effect of increasing crystal size. An Arrhenius plot of PL integrated area is used to calculate the thermal activation energy value E a of the non-radiative recombination channel, which is 132 meV for CdTe QDs and a higher value of 185 meV for Cd x Zn1−x Te QDs. This is consistent with the observed QY enhancement in Cd x Zn1−x Te QDs as a higher E a value indicates reduced generation of non-radiative recombination centres and a decrease in defect densities upon alloying. Cd x Zn1−x Te QDs with enhanced fluorescence properties serve both as a medium for studying fundamental effects of alloying and its properties, and for practical applications such as biomedical labelling and optoelectronics.

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II-VI Semiconductors Bandgap Engineering

Kurban

Şımşek

Erkoç

2023

Handbook of II-VI Semiconductor-Based Sensors and Radiation Detectors

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Size and temperature dependence of the photoluminescence properties of NIR emitting ternary alloyed mercury cadmium telluride quantum dots

Cited by 10 publications

References 55 publications

Sodium Chloride Protected CdHgTe Quantum Dot Based Solid-State Near-Infrared Luminophore for Light-Emitting Devices and Luminescence Thermometry

Sodium Chloride Protected CdHgTe Quantum Dot Based Solid-State Near-Infrared Luminophore for Light-Emitting Devices and Luminescence Thermometry

Temperature- and size-dependent photoluminescence in colloidal CdTe and Cd _x Zn_1−xTe quantum dots

II-VI Semiconductors Bandgap Engineering

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Size and temperature dependence of the photoluminescence properties of NIR emitting ternary alloyed mercury cadmium telluride quantum dots

Cited by 10 publications

References 55 publications

Sodium Chloride Protected CdHgTe Quantum Dot Based Solid-State Near-Infrared Luminophore for Light-Emitting Devices and Luminescence Thermometry

Sodium Chloride Protected CdHgTe Quantum Dot Based Solid-State Near-Infrared Luminophore for Light-Emitting Devices and Luminescence Thermometry

Temperature- and size-dependent photoluminescence in colloidal CdTe and Cd x Zn1−x Te quantum dots

II-VI Semiconductors Bandgap Engineering

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Product

Resources

About

Temperature- and size-dependent photoluminescence in colloidal CdTe and Cd _x Zn_1−xTe quantum dots