Absorption and emission in the visible range by ultra-small PbS quantum dots in the strong quantum confinement regime with S-terminated surfaces capped with diphenylphosphine

Gómez, Nayely Torres; García-Gutiérrez, Diana F.; Lara-Canche, Alan  R.; Triana-Cruz, Lizbeth; Arizpe-Zapata, Alejandro; García-Gutiérrez, Domingo I.

doi:10.1016/j.jallcom.2020.158443

Cited by 14 publications

(4 citation statements)

References 46 publications

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“…It was found in [30] for PbS nanocrystals in glass that, for the peak of the absorption exciton transition with an energy in the range from 0.8 to 1.4 eV, the Stokes shift weakly depends on the size and does not exceed 0.12 eV, that is noticeably smaller than in [25,26,31].…”

Section: Introductionmentioning

confidence: 93%

“…In [26], for PbS QDs with an average size of about 2 nm and exciton absorption peak at 560 nm (2.21 eV), the Stokes shift of 0.39 eV was demonstrated. It is noticeably smaller than the similar value in [1,25].…”

Section: Introductionmentioning

confidence: 96%

“…Increased attention to this material is due to the possibility to use it in the infrared range, since the band gap is 0.41 eV [24]. Decreasing the crystals size to 1-20 nm due to the quantum size effect, makes it possible to tune the absorption and luminescence bands from the IR to visible region [1,[25][26][27][28][29][30][31]. However, at the present time there is no unified point of view regarding the criteria for establishing the QDs luminescence mechanism.…”

Section: Introductionmentioning

confidence: 99%

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Size effect in PbS Quantum Dots Luminescence

Grevtseva

Chevychelova

Ovchinnikov

et al. 2022

Preprint

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This paper presents new regularities of the size effect in IR luminescence of semiconductor colloidal PbS quantum dots, passivated with thioglycolic acid molecules (PbS/TGA QDs). It was found that decrease in the average PbS/TGA QDs size of the sample from 4.9 nm to 2.6 nm produces the luminescence peak shifts from 1350 nm to 865 nm. At that time, in the excitation spectrum the peak due to exciton absorption shifts from 1235 nm to 707 nm. The Stokes shift increases from 0.086 to 0.32 eV. The study of time-resolved luminescence showed that the luminescence decay is complex non-exponential it, that is determined by the statistical distribution of luminescence quenchers in PbS/TGA QDs over the ensemble. The complex of the obtained experimental results made it possible to conclude that the observed luminescence is determined by the radiative annihilation of exciton in PbS/TGA QDs.

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Section: Introductionmentioning

confidence: 93%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Size effect in PbS Quantum Dots Luminescence

Grevtseva

Chevychelova

Ovchinnikov

et al. 2022

Preprint

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“…The lifetime of this exciton, along with the optical gain, is a crucial parameter in characterizing quantum dots (QDs). In low-dimension structures, the strong confinement of the charge carriers leads to the quantification of the energy levels in such a way that both the absorption and emission spectrums, arising from the transition between the discrete electron and hole energy levels, are highly sensitive to QD shapes and sizes [8,9]. In the literature, the optical properties of excitons, such as lifetime, optical gain (OG), and oscillator strengths (OS), have been extensively studied for different types of QDs [10][11][12][13][14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Optical Gain of a Spherical InAs Quantum Dot under the Effects of the Intense Laser and Magnetic Fields

et al. 2023

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In quantum dots, where confinement is strong, interactions between charge carriers play an essential role in the performance of semiconductor materials for optical gain. Therefore, understanding this phenomenon is critical for achieving new devices with enhanced features. In this context, the current study examines the optical properties of an exciton confined in a spherical InAs quantum dot under the influence of magnetic and intense laser fields. We investigate the oscillator strength, exciton lifetime, and optical gain, considering the effects of both external fields. We also pay particular attention to the influence of quantum dot size on the results. Our calculations show that the two external fields have opposite effects on our findings. Specifically, the applied magnetic field increases the oscillator strength while the intense laser reduces it. In addition, the optical gain peaks are redshifted under the application of the intense laser, whereas the magnetic field causes a blueshift of the peak threshold. We also find that both external perturbations significantly influence the exciton lifetime. Our study considers the outcomes of both the exciton’s ground (1s) and first excited (1p) states. The theoretical results obtained in this study have promising implications for optoelectronic devices in the ∼3–4 μm wavelength range only through the control of quantum dot sizes and external perturbations.

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