Origin of the blue and red photoluminescence from aged porous silicon

Li, Peng; Wang, Guanzhong; Ma, Yurong; Fang, Rongchuan

doi:10.1103/physrevb.58.4057

Cited by 37 publications

(22 citation statements)

References 42 publications

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“…21 For nanocrystals contained in porous silicon, the aging effects were found to modify the optical properties of the sample, as redshift and width increase in PL spectra. 27,28 …”

Section: B Qds Suspended In Thfmentioning

confidence: 99%

Quantum yield excitation spectrum (UV-visible) of CdSe/ZnS core-shell quantum dots by thermal lens spectrometry

Cruz

Pilla

Catunda

2010

Journal of Applied Physics

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A recently developed thermal lens spectrometry configuration has been used to study CdSe/ZnS core-shell quantum dots ͑QDs͒ suspended in toluene and tetrahydrofuran ͑THF͒ solvents. The special features of this configuration make it very attractive to measure fluorescence quantum yield ͑͒ excitation spectrum since it simplifies the measurement procedure and consequently improve the accuracy. Furthermore, the precision reached is much higher than in conventional photoluminescence ͑PL͒ technique. Two methods, called reference sample and multiwavelength have been applied to determine , varying excitation wavelength in the UV-visible region ͑between 335-543 nm͒. The and PL spectra are practically independent of the excitation wavelength. For CdSe/ZnS QDs suspended in toluene we have obtained =76Ϯ 2%. In addition, the aging effect on and PL has been studied over a 200 h period for QDs suspended in THF.

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“…21 For nanocrystals contained in porous silicon, the aging effects were found to modify the optical properties of the sample, as redshift and width increase in PL spectra. 27,28 …”

Section: B Qds Suspended In Thfmentioning

confidence: 99%

Quantum yield excitation spectrum (UV-visible) of CdSe/ZnS core-shell quantum dots by thermal lens spectrometry

Cruz

Pilla

Catunda

2010

Journal of Applied Physics

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“…Apparently, oxygen-related defects are generated simultaneously as the oxidation of the Si nanoparticles takes place. 14 The wavelength and half width of this new blue peak are nearly the same as those of the initially blue-emitting PS.…”

Section: Resultsmentioning

confidence: 50%

Aging behavior of porous silicon electrochemically etched with the aid of Zn

Suh

Kim

Lee

2001

Journal of Applied Physics

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Aging behavior of red, green, and blue photoluminescence from porous silicon formed by electrochemical etching aided with zinc has been studied over a 3 month time span. Time-resolved photoluminescence spectra and decay dynamics have revealed that there are two radiating states in Zn-aided porous silicon. One is the quantum confinement and the other is the oxygen-related defect. For green emission, the wavelength shifts from 520 to 420 nm and its photoluminescence spectra and decay behavior become very similar to those of blue emission.

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“…The blue fluorescence in most cases is attributed to the oxidized surface states [15][16][17][18], although extremely small Si crystals -nanocrystallites could recreate the same behavior [14]. Red fluorescence band usually attributed to nanometer sized Si nanocrystallites [19][20][21][22][23] is also inhomogeneous: fluorescence at different wavelengths decays with different rates and is attributed to nanocrystallites of different dimensions.…”

mentioning

confidence: 95%

Excitation energy transfer in porous silicon/laser dye composites

Pranculis

Šimkienė

Treideris

et al. 2013

Phys. Status Solidi A

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Excited state relaxation and energy transfer in porous silicon (PS)/laser dye [oxazine 1 (Ox1), rhodamine 6G (Rh6G)] composites have been studied by means of steady-state and time-resolved fluorescence. Fluorescence decay kinetics reveals the nonradiative energy transfer from PS to the dye. Increased decay rate of the dye luminescence in the composite indicates that opposite energy transfer is also likely. Analysis of the time-resolved fluorescence of the PS/R6G composite also shows that there is no energy transfer from silicon oxide responsible for the "blue" fluorescence band to silicon nanocrystalites, and that interaction between Si nanocrystals responsible for the "red" PS fluorescence is absent or weak. 1 Introduction Since its discovery, porous silicon (PS) proved to be a non-trivial fluorescent system. Having many different energy levels, each with its own relaxation time and at least two distinct fluorescence mechanisms (surface oxide and Si nanocrystallites) PS is still not fully understood.PS/organic material composites were first investigated few years after the discovery of the visible luminescence of PS. Polymers were spin-coated onto PS in order to produce hybrid LEDs with variable fluorescence spectra [1-3], while laser dye impregnation into the pores was motivated by possible application of such composites in laser physics [4][5][6][7]. One of the key processes in such systems -energy transfer, attracted most of the researcher's attention because of its natural complexity resulting from intricate fluorescence of PS.In 1993 Canham [8] reported impregnation of PS with laser dye in order to get a solid state host for optically active media -a goal of great interest still. In his work Canham examined possible energy transfer in such composites. Since then, driven by possible applications of such materials in optoelectronics, a number of researchers investigated PS/ laser dye composites using different techniques and reported energy transfer from PS to the dye as their main findings [9][10][11][12][13].Time-gated fluorescence of PS reveals two bands -high energy "blue" fluorescence, which is intensive but decays in less than 5 ns, and low energy "red" fluorescence, which is

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Origin of the blue and red photoluminescence from aged porous silicon

Cited by 37 publications

References 42 publications

Quantum yield excitation spectrum (UV-visible) of CdSe/ZnS core-shell quantum dots by thermal lens spectrometry

Quantum yield excitation spectrum (UV-visible) of CdSe/ZnS core-shell quantum dots by thermal lens spectrometry

Aging behavior of porous silicon electrochemically etched with the aid of Zn

Excitation energy transfer in porous silicon/laser dye composites

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