Size dependence of upconversion photoluminescence in MPA capped CdTe quantum dots: Existence of upconversion bright point

Soosaimanickam, Ananthakumar; Jayabalan, J.; Singh, Asha; Khan, S.; Babu, S. Moorthy; Chari, Rama

doi:10.1016/j.jlumin.2015.09.019

Cited by 10 publications

(3 citation statements)

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“…This entails observations of redshifted ASPL spectra relative to the normal NC/nanostructure band edge emission. These redshifts have been observed in CdS 1 − x Se x 110 , CdSe 59,62,109 , CdTe 59,63,65,66,71,105,112,113 , PbS NC-doped glasses 67,115 , CsPbBr 3 73,103 , and CsPbBrI 2 NCs 69 . Figure 9a provides an example, showing the apparent~8 meV redshift between the emission and ASPL spectra of a CsPbBr 3 NC ensemble.…”

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confidence: 74%

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Progress in laser cooling semiconductor nanocrystals and nanostructures

et al. 2019

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Over the past two decades, there have been sizable efforts to realize condensed phase optical cooling. To date, however, there have been no verifiable demonstrations of semiconductor-based laser cooling. Recently, advances in the synthesis of semiconductor nanostructures have led to the availability of high-quality semiconductor nanocrystals, which possess superior optical properties relative to their bulk counterparts. In this review, we describe how these nanostructures can be used to demonstrate condensed phase laser cooling. We begin with a description of charge carrier dynamics in semiconductor nanocrystals and nanostructures under both above gap and below-gap excitation. Two critical parameters for realizing laser cooling are identified: emission quantum yield and upconversion efficiency. We report the literature values of these two parameters for different nanocrystal/nanostructure systems as well as the measurement approaches used to estimate them. We identify CsPbBr 3 nanocrystals as a potential system by which to demonstrate verifiable laser cooling given their ease of synthesis, near-unity emission quantum yields and sizable upconversion efficiencies. Feasibility is further demonstrated through numerical simulations of CsPbBr 3 nanocrystals embedded in an aerogel matrix. Our survey generally reveals that optimized semiconductor nanocrystals and nanostructures are poised to demonstrate condensed phase laser cooling in the near future.

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confidence: 74%

“…, and PhEPbI 3 nanoplatelets 50 . Although occasional quadratic/near-quadratic growth has been reported 68,70,71,[109][110][111][112][113] , the bulk of the available literature points to the dominant role played by one-photon and, by corollary, defect-mediated processes in NC/nanostructure ASPL.…”

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confidence: 99%

Progress in laser cooling semiconductor nanocrystals and nanostructures

et al. 2019

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“…Para quase todo mecanismo UC, a intensidade da emissão UC visível de saída (IUC) será proporcional a potência da fonte de excitação do infravermelho (PIR) como mostrado na equação 11: (ANANTHAKUMAR et al, 2016;POLLNAU et al, 2000;VETRONE et al, 2004): , 2000). Este "efeito de saturação" é especialmente visível para energias mais altas do laser de bombeamento ou para sistemas onde as taxas up-conversion são altas.…”

Section: Teoria Do Processo De Conversão Ascendente (Up-conversion)unclassified

Propriedades fotoluminescentes da matriz cerâmica BaBi2Nb2O9 (BBN) tri-dopada com Er3+/Tm3+/Yb3+

FAÇANHA¹

2022

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AGRADECIMENTOSÀ CAPES, pelo apoio financeiro com a manutenção da bolsa de auxílio.À Universidade Federal do Ceará pelo suporte fornecido para minha formação nos cursos de graduação, mestrado e doutorado.Ao professor Dr. Antonio Sergio Bezerra Sombra pelo suporte, orientação, e incentivo na realização desse trabalho.Ao laboratório de Difração de Raios-X da UFC pelas medidas realizadas.A todos os integrantes da Central Analítica -UFC pelas análises de MEV.

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An investigation on the structural and optical properties of mercaptosuccinic acid capped cadmium telluride quantum dots

et al. 2023

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In this work, a sonication induced modified wet chemical approach is adopted to synthesize highly luminescent and water soluble cadmium telluride (CdTe) quantum dots (QDs). The morphology, size, crystal structural, and optical properties of CdTe QDs are investigated for different refluxing time (1–4 h). The refluxing time-dependent optical constants viz. band gap energy and Urbach energy of the QDs are estimated from UV–Visible absorption spectra. The optical band gap energy decreased from ~ 2.12 to 1.92 eV and the Urbach energy increased from ~ 361 to 487 meV, with the increase in refluxing time. CdTe QDs are found to be uniform in size. The average size of the QDs estimated from the High Resolution Transmission Electron Microscope image analysis is about 5.8 and 8.2 nm for refluxing times 1 and 4 h, respectively. The growth mechanism of the QDs as a function of refluxing time has also been discussed. The fluorescence spectra of the QDs, revealed emission peaks having wavelength from ~ 534 to 585 nm, under the excitation wavelength of 320 nm. The fluorescence emission peaks showed a bathochromic shift with increasing refluxing time. CdTe QDs also exhibit excitation-dependent fluorescence behaviour. Two crystalline phases of the CdTe QDs, namely hexagonal and cubic are confirmed from the High Resolution Transmission Electron Microscope images and Selected Area Electron Diffraction patterns analysis. The phase transformation from hexagonal to cubic is successfully achieved by tuning the refluxing time from 1 to 4 h.

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Size dependence of upconversion photoluminescence in MPA capped CdTe quantum dots: Existence of upconversion bright point

Cited by 10 publications

References 38 publications

Progress in laser cooling semiconductor nanocrystals and nanostructures

Progress in laser cooling semiconductor nanocrystals and nanostructures

Propriedades fotoluminescentes da matriz cerâmica BaBi2Nb2O9 (BBN) tri-dopada com Er3+/Tm3+/Yb3+

An investigation on the structural and optical properties of mercaptosuccinic acid capped cadmium telluride quantum dots

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