Size‐dependent temperature sensitivity of photoluminescence peak position of CdTe quantum dots

Vyhnan, N. M.; Khalavka, Yuriy

doi:10.1002/bio.2600

Cited by 16 publications

(10 citation statements)

References 17 publications

(16 reference statements)

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“…We noticed that similar to optical bandgap (Eg opt ), electrochemical (Eg CV ) bandgap of QDs demonstrates the same trend, so the temperature sensitivity of QDs of a certain size can be determined from the slope of the linear regression approximation plotted in the coordinates Eg vs. αT 2 / (T + θ). In this case, the temperature coefficient α will describe the change in the PL energy when the temperature is changed by 1 K, and E 0 is the PL energy at 0 K [23].…”

Section: Temperature-dependent Bandgap Variation In Cdte/cds Qdsmentioning

confidence: 99%

Temperature Dependence of the Bandgap of CdTe/CdS Core–Shell Quantum Dots

Tynkevych

Vyhnan

Fochuk

et al. 2015

Springer Proceedings in Physics

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Quantum dots or semiconductor nanocrystals exhibit the so-called quantum confinement effect when synthesized with a crystallite size below to Bohr exciton radius of the bulk material. The QDs are characterized by the physical and chemical properties which significantly differ from their individual molecules or bulk forms [1]. The quantum confinement effect gives rise to unique size-dependent electrooptical properties, which are important for their potential use in lasers, solid-state lighting, solar cells, and biomedical fields [2][3][4][5][6][7]. While optical absorption measurements yield information on the QD size and the relative energy level configurations, they do not allow the determination of absolute energy levels positioned with respect to a standard potential. These values are vital for completing our understanding of the confinement effect in QDs. The most common method for the determination of the size-dependent conduction and valence band edge shift in quantum confined systems to date is cyclic voltammetry (CV) [8].Studies on the temperature dependence of QDs optical and electrochemical properties are important for their potential application because the desired device should emit in the visible spectral range at room temperature.Previous works by Poznyak et al.

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Section: Temperature-dependent Bandgap Variation In Cdte/cds Qdsmentioning

confidence: 99%

Temperature Dependence of the Bandgap of CdTe/CdS Core–Shell Quantum Dots

Tynkevych

Vyhnan

Fochuk

et al. 2015

Springer Proceedings in Physics

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“…There are only few publications that investigate the temperature dependence of the band gap energy on nanoparticles. 49 The effects that can influence the band gap shift and the line broadening under discussion are, for example, the strain in the crystal lattice, the termination of the dangling bonds at the nanoparticle surface, the temperature of the nanoparticle, and the change of the effective electron/hole mass due to changes in the band structure.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic Properties of Semiconductor Nanoparticles near the Solid-to-Liquid Phase Transition

2023

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Gas-phase synthesis of semiconductor nanoparticles is often supported by optical in situ measurements to determine the particle size, phase, and volume fraction. These attributes are connected to the optical properties of these particles, which depend strongly on the temperature and particle size as well as the phase transition near the melting point. To support such measurements, we derive a Lorentz-oscillator model for solid silicon and germanium with temperature- and particle-size-dependent transition energies, line widths, and oscillator strengths. The model yields the complex dielectric function that is then processed using Mie theory to calculate size-dependent absorption and scattering cross-sections for nanoparticles as well as nanoparticle aerosols.

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“…The fitted α values were in the range of (2.9–3.4) × 10 −4 eV/K, which is very close to the value of bulk CdTe (0.3 × 10 −4 eV/K) [ 33 ]. The β values changed from 312 to 146 K for CdTe NC/PVA films with larger sizes, which were similar to that of bulk CdTe (160 K) [ 34 ], due to lattice softening from bulk to NCs [ 35 ]. The fitting results showed that the tendency of the temperature-dependent bandgap was consist with traditional II-VI NCs.…”

Section: Resultsmentioning

confidence: 99%

Temperature-Dependent Excitonic Photoluminescence and Nonlinear Absorption of CdTe Nanocrystal/Polyvinyl Alcohol Films

et al. 2021

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The temperature dependence of the excitonic photoluminescence (PL) and nonlinear absorption characteristics of CdTe nanocrystals (NCs)/polyvinyl alcohol (PVA) film are investigated using steady-state/time-resolved PL spectroscopy and Z-scan methods. The excitonic PL peaks of CdTe NCs can be observed at the wavelengths from 560 to 670 nm, with size changes from 2.1 to 3.9 nm. From the temperature-dependent PL spectra, the smaller photon energy of the PL emission peak, the rapidly decreasing PL intensity, and the wider linewidth are observed with increasing temperature from 80 to 300 K. It is revealed that the exciton PL is composed of both trapped state and band-edge excitonic state, which presents biexponential fitting dynamics. The short-lived species is due to the surface-trapped state recombination in NCs, which has a photogenerated trapped channel and a time-resolved peak shift. The species with a long-lived lifetime is ascribed to the intrinsic excitonic recombination. Through the femtosecond Z-scan method, the nonlinear absorption coefficient becomes smaller with the increase in the size of the NCs. The optical properties of the CdTe NC/PVA film show the potential of II-VI traditional NCs as display and luminescent materials that can utilize the combination of exciton PL and nonlinear absorption for expanded functionality.

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Size‐dependent temperature sensitivity of photoluminescence peak position of CdTe quantum dots

Cited by 16 publications

References 17 publications

Temperature Dependence of the Bandgap of CdTe/CdS Core–Shell Quantum Dots

Temperature Dependence of the Bandgap of CdTe/CdS Core–Shell Quantum Dots

Spectroscopic Properties of Semiconductor Nanoparticles near the Solid-to-Liquid Phase Transition

Temperature-Dependent Excitonic Photoluminescence and Nonlinear Absorption of CdTe Nanocrystal/Polyvinyl Alcohol Films

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