Control the shallow trap states concentration during the formation of luminescent Ag2S and Ag2S/SiO2 core/shell quantum dots

Ovchinnikov, O. V.; Perepelitsa, A. S.; S., None Smirnov M.; Aslanov, S. V.

doi:10.1016/j.jlumin.2021.118616

Cited by 9 publications

(2 citation statements)

References 42 publications

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“…If the increase in the Stokes shift under decreasing temperature to 80 K is determined by the charge carriers capture by trap with this depth (longwavelength shift of the luminescence peak), then the lifetime of a trapped charge carrier can be estimated using a simple equation [42]…”

Section: Photoluminescence Excitation Spectra and Decay Of Luminescencementioning

confidence: 99%

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: Photoluminescence Excitation Spectra and Decay Of Luminescencementioning

confidence: 99%

Size effect in PbS Quantum Dots Luminescence

Grevtseva

Chevychelova

Ovchinnikov

et al. 2022

Preprint

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“…Riedesel et al (2021) investigated two mechanisms as possible explanations for the increase in IR excited luminescence with temperature in feldspars, but they did not make a convincing case for either of them. Ovchinnikov et al (2022) found that during irradiation photons of energy around 1.43 eV are emitted. They concluded that the mechanism for this emission was electrons dropping into traps that were emptied during IR excitation.…”

Section: = I 0 Exp( − λT)mentioning

confidence: 99%

Luminescence measurement of Feldspar

Uzorka¹

2022

Preprint

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In their ideal form, feldspars are wide bandgap (> 5 eV) insulators with a well-defined crystal structure. A natural sample may contain different feldspar phases, disorders, twinning effects, fractures, dislocations, and highly variable impurity contents. With such messy materials, one might expect that exposing the samples to ionizing radiation would alter the structure so that the results from a single feldspar would not be reproducible. However, one finds that the luminescence emission changes with sample temperature in a similar way for different feldspars and decays away with prolonged Infrared (IR) exposure at a similar rate. In these experiments, the luminescence intensities of irradiated aliquots of A1, K3, K6, and VI.1 were measured while they were exposed to 850 nm exciting light either for long periods at constant aliquot temperature or while the aliquot temperature was changed during the optical excitation. I found that the luminescence intensity decreased with time for all sample aliquots, and all emission bands if the optical excitation and the aliquot temperature remained constant. The decay rate for the luminescence from K3 was found to be independent of temperature, but for the other samples, it was not. Our results are consistent with a model consisting of one type of trap, and electrons excited from these traps recombine at different luminescence centers producing the different emission bands. Differences in the activation energy and work function values between our samples for the same emission band, and between our samples and those of others, are interpreted as being caused by slightly different environments around the traps and luminescence centers.

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