Toward Ratiometric Nanothermometry via Intrinsic Dual Emission from Semiconductor Nanocrystals

Jethi, Lakshay; Krause, Michael; Kambhampati, Patanjali

doi:10.1021/acs.jpclett.5b00024

Cited by 63 publications

(68 citation statements)

References 19 publications

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“…31 In a related approach, the thermal equilibrium between band edge and defect emission of CdSe dots could be used for nanothermometry and in LEDs. 47,48 …”

Section: Ratiometric Sensingmentioning

confidence: 99%

Colloidal Double Quantum Dots

et al. 2016

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ConspectusPairs of coupled quantum dots with controlled coupling between the two potential wells serve as an extremely rich system, exhibiting a plethora of optical phenomena that do not exist in each of the isolated constituent dots. Over the past decade, coupled quantum systems have been under extensive study in the context of epitaxially grown quantum dots (QDs), but only a handful of examples have been reported with colloidal QDs. This is mostly due to the difficulties in controllably growing nanoparticles that encapsulate within them two dots separated by an energetic barrier via colloidal synthesis methods. Recent advances in colloidal synthesis methods have enabled the first clear demonstrations of colloidal double quantum dots and allowed for the first exploratory studies into their optical properties. Nevertheless, colloidal double QDs can offer an extended level of structural manipulation that allows not only for a broader range of materials to be used as compared with epitaxially grown counterparts but also for more complex control over the coupling mechanisms and coupling strength between two spatially separated quantum dots.The photophysics of these nanostructures is governed by the balance between two coupling mechanisms. The first is via dipole–dipole interactions between the two constituent components, leading to energy transfer between them. The second is associated with overlap of excited carrier wave functions, leading to charge transfer and multicarrier interactions between the two components. The magnitude of the coupling between the two subcomponents is determined by the detailed potential landscape within the nanocrystals (NCs).One of the hallmarks of double QDs is the observation of dual-color emission from a single nanoparticle, which allows for detailed spectroscopy of their properties down to the single particle level. Furthermore, rational design of the two coupled subsystems enables one to tune the emission statistics from single photon emission to classical emission. Dual emission also provides these NCs with more advanced functionalities than the isolated components. The ability to better tailor the emission spectrum can be advantageous for color designed LEDs in lighting and display applications. The different response of the two emission colors to external stimuli enables ratiometric sensing. Control over hot carrier dynamics within such structures allows for photoluminescence upconversion.This Account first provides a description of the main hurdles toward the synthesis of colloidal double QDs and an overview of the growing library of synthetic pathways toward constructing them. The main discoveries regarding their photophysical properties are then described in detail, followed by an overview of potential applications taking advantage of the double-dot structure. Finally, a perspective and outlook for their future development is provided.

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“…31 In a related approach, the thermal equilibrium between band edge and defect emission of CdSe dots could be used for nanothermometry and in LEDs. 47,48 …”

Section: Ratiometric Sensingmentioning

confidence: 99%

Colloidal Double Quantum Dots

et al. 2016

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“…It also reduces the impact of external factors that alter absolute intensities (fl uctuation of excitation intensity, detection effi ciency, and optical occlusion) and offers a self-referencing luminescent thermometry method which does not require calibration. [ 9,33,34,66 ] The CdTe QDs@NaCl powders feature an intrinsic dual-emission temperature-dependent luminescence, which enables their use in self-referencing luminescent thermometry. The ratio of the integrated PL intensity of the excitonic (core) band for the sample with d QDs = 2.3 nm relative to that of the trap-related (surface) band shows a monotonic decrease with falling temperature (Figure 8 …”

Section: Ratiometric Luminescent Thermal Sensing Via Intrinsic Dual Ementioning

confidence: 99%

“…The absolute pseudo linear sensitivity of this ratiometric CdTe QDs@NaCl thermal probe is 0.007 K −1 and the maximum relative sensitivity is 0.61% K −1 at T = 199 K, which is comparable to the best values for thermal sensitivity provided by a ratiometric luminescent thermometry method. [ 6,33,65,66 ] For this ratiometric sensing method smaller QDs have the advantage of a potentially wider operating temperature range as larger QDs show less trap-related emission at lower temperatures ultimately limiting the lower operating temperature.…”

Section: Ratiometric Luminescent Thermal Sensing Via Intrinsic Dual Ementioning

confidence: 99%

Temperature-Dependent Exciton and Trap-Related Photoluminescence of CdTe Quantum Dots Embedded in a NaCl Matrix: Implication in Thermometry

Kalytchuk

Zhovtiuk

Kershaw

et al. 2015

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Temperature-dependent optical studies of semiconductor quantum dots (QDs) are fundamentally important for a variety of sensing and imaging applications. The steady-state and time-resolved photoluminescence properties of CdTe QDs in the size range from 2.3 to 3.1 nm embedded into a protective matrix of NaCl are studied as a function of temperature from 80 to 360 K. The temperature coefficient is found to be strongly dependent on QD size, with the highest sensitivity obtained for the smallest size of QDs. The emission from solid-state CdTe QD-based powders is maintained with high color purity over a wide range of temperatures. Photoluminescence lifetime data suggest that temperature dependence of the intrinsic radiative lifetime in CdTe QDs is rather weak, and it is mostly the temperature-dependent nonradiative decay of CdTe QDs which is responsible for the thermal quenching of photoluminescence intensity. By virtue of the temperature-dependent photoluminescence behavior, high color purity, photostability, and high photoluminescence quantum yield (26%-37% in the solid state), CdTe QDs embedded in NaCl matrices are useful solid-state probes for thermal imaging and sensing over a wide range of temperatures within a number of detection schemes and outstanding sensitivity, such as luminescence thermochromic imaging, ratiometric luminescence, and luminescence lifetime thermal sensing.

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“…In addition to conventional NCs that only emit from the core excitonic state, a growing amount of publications focus on small NCs that also display a broad and redshifted surface PL peak. (7)(8)(9) Not only has this observable been analyzed in order to explain NC exciton dynamics, but there are detailed accounts of how surface manipulations make these systems potential candidates for lighting (10)(11) and sensing (12) applications.…”

Section: Toc Graphicsmentioning

confidence: 99%

Ligand Surface Chemistry Dictates Light Emission from Nanocrystals

Krause

Jethi

Mack

et al. 2015

J. Phys. Chem. Lett.

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There are several contradictory accounts of the changes to the emissive behavior of semiconductor nanocrystal upon a ligand exchange from trioctylphosphine/cadmium-phosphonates passivation to N-butylamine. This communication explains the contradictory accounts of this reaction using new insights into ligand chemistry. Also, a previously unknown link between surface emission and cadmium-phosphonate (Z-type) ligands is shown.

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Toward Ratiometric Nanothermometry via Intrinsic Dual Emission from Semiconductor Nanocrystals

Cited by 63 publications

References 19 publications

Colloidal Double Quantum Dots

Colloidal Double Quantum Dots

Temperature-Dependent Exciton and Trap-Related Photoluminescence of CdTe Quantum Dots Embedded in a NaCl Matrix: Implication in Thermometry

Ligand Surface Chemistry Dictates Light Emission from Nanocrystals

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