Temperature dependence of the exciton transition in semiconductor quantum dots

Liptay, Thomas J.; Ram, Rajeev J.

doi:10.1063/1.2400107

Cited by 47 publications

(46 citation statements)

References 16 publications

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“…7b and c). Considering the fact that the temporary peak shift of 45 meV with temperature (from RT to 420 o C) is constant for QDs of all sizes [14], the calculated RT exciton absorption peak after heat treatment is 0.56 eV (at 420 o C) + 0.045 eV (offset) = 0.605 eV (at RT), which is in agreement with the measured RT absorption spectra (red dotted curve in Fig. 7c).…”

Section: Real Time Quantum Dot Growth Monitoringsupporting

confidence: 77%

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PbSe quantum dots grown in a high-index, low-melting-temperature glass for infrared laser applications

et al. 2013

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PbSe quantum dots (QDs) were grown in high-refractive-index low-melting-temperature leadphosphate glass. QDs with various sizes ranging from 2 nm to 5.3 nm were grown by controlling the growth parameters, heat-treatment temperature and time. The corresponding room-temperature exciton absorption was tuned within the infrared region from 0.93 µm to 2.75 µm. Photoluminescence was measured for samples with absorption peaks above 0.95eV. Real time quantum dot growth was demonstrated by monitoring the evolution of exciton absorption with temperature and time duration. As a demonstration of the use of QDs in laser applications, the saturation fluence (F sat ) of one of the QDs was evaluated and found to be ~2.1 µJ/cm 2 at 1.2 µm.

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Section: Real Time Quantum Dot Growth Monitoringsupporting

confidence: 77%

“…6b. A shift of 45 meV was observed on heating the sample from RT to 420 o C. This shift is temporary and retraces the peak positions with temperature as the temperature is reduced to RT, which is due to the variation in the confinement energy of the QDs [14].…”

Section: Real Time Quantum Dot Growth Monitoringmentioning

confidence: 97%

PbSe quantum dots grown in a high-index, low-melting-temperature glass for infrared laser applications

et al. 2013

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“…[16,[18][19][20][21][22][23] We found also that the ultra-small CdS NCs stabilized by Cd(II) complexes with PEI or NH 3 /MA reveal unusually strong temperature dependences of both absorption edge and PL intensity when probed in aqueous colloidal solutions, [21,22] showing a peculiar PL quenching mechanism differing from that typical for "regular" CdX NCs capped by covalently bound ligands. [25][26][27][28][29][30][31] In the present work we explore the variations of PL parameters of GSH-capped AIS (AIS/ZnS) NCs produced directly in aqueous solutions in the temperature window of 10-80°C in comparison with previously studied ultra-small CdX NCs capped with Cd(II) complexes. The thermal sensitivity of these NCs appears to be governed by general mechanisms involving complex dissociation/association equilibiria on the NC surface.…”

Section: Introductionmentioning

confidence: 99%

Temperature‐Dependent Photoluminescence of Silver‐Indium‐Sulfide Nanocrystals in Aqueous Colloidal Solutions

et al. 2019

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The temperature dependence of the photoluminescence (PL) intensity of colloidal semiconductor nanocrystals (NCs) makes them an appealing option in bio‐sensing applications. Here, we probed the temperature‐dependent PL behavior of aqueous glutathione (GSH)‐capped Ag−In−S (AIS) NCs and their core/shell AIS/ZnS heterostructures. We show that both core and core‐shell materials reveal strong PL quenching upon heating from 10 to 80 °C, which is completely reversible upon cooling. The PL quenching is assigned to the thermally activated dissociation of complexes formed by ligands with the metal cations on the NC surface and the introduction of water into the NC coordination sphere. This unique mechanism of the thermal PL quenching results in a much higher temperature sensitivity of the aqueous colloidal AIS (AIS/ZnS) NCs as compared with previously reported analogs capped by covalently bound ligands. Our results are expected to stimulate further studies on aqueous ternary NCs as colloidal luminescent nano‐thermometers applicable for ratiometric temperature sensing.

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“…[27,[83][84][85][86][87] One should note that the existence of "kink" has up to now only been reported with respect to the PL properties of QDs. Unusual "luminescence antiquenching" at a well defined temperature of T∼250 K (manifested in our experiments as "kink") has been observed for CdTe or CdSe/ZnS QDs initially dissolved in liquid solutions such as toluene, and has been related to a phase transition in the surfactant capping layer.…”

Section: Ligand Capping Phase Transitions In "Qd-dye" Nanocomposites mentioning

confidence: 99%

Ligand Exchange Dynamics and Temperature Effects upon Formation of Nanocomposites Based on Semiconductor CdSе/ZnS Quantum Dots and Porphyrins: Ensemble and Single Object Measurements

Zenkevich¹,

Blaudeck²,

Kowerko³

et al. 2012

MHC

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Dye molecules with pyridyl side substituents (porphyrins and heterocyclic perylene diimides) coordinatively attached to semiconductor CdSe/ZnS quantum dots (QDs) surface form quasi-stable "QD-Dye" nanocomposites of various geometry in the competition with capping molecules (tri-n-octyl phosphine oxide or long chain amines) exchange. This results in photoluminescence (PL) quenching of the QDs both due to Foerster resonance energy transfer and formation of non-radiative surface states. QD surface is inhomogeneous with respect to the involved attachment and detachment processes. The formation of "QD-Porphyrin" nanocomposites is realized at least two time scales (60 and 600 s), which is attributed to a reorganisation of tri-n-octylphosphine oxide capping shell. In a low temperature range of 220÷240 K related changes in QD absorption and emission reveal a phase transition of the capping shell (tri-n-octyl phosphine oxide and amine). In "QD-Dye" nanocomposites, this phase transition is enhanced considerably by only a few attached

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Temperature dependence of the exciton transition in semiconductor quantum dots

Cited by 47 publications

References 16 publications

PbSe quantum dots grown in a high-index, low-melting-temperature glass for infrared laser applications

PbSe quantum dots grown in a high-index, low-melting-temperature glass for infrared laser applications

Temperature‐Dependent Photoluminescence of Silver‐Indium‐Sulfide Nanocrystals in Aqueous Colloidal Solutions

Ligand Exchange Dynamics and Temperature Effects upon Formation of Nanocomposites Based on Semiconductor CdSе/ZnS Quantum Dots and Porphyrins: Ensemble and Single Object Measurements

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