Energy Transfer in Quantum Dot Solids

Kholmicheva, Natalia; Moroz, Pavel; Eckard, Holly; Jensen, Gregory C.; Zamkov, Mikhail

doi:10.1021/acsenergylett.6b00569

Cited by 101 publications

(115 citation statements)

References 46 publications

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“…23 These experiments reveal that Förster theory correctly predicts scaling parameters that affect the energy transfer rate in QD solids. 15,16,19,22,26 To understand the dynamics of excitons in QD solids, let us consider a model QD solid system that is illustrated in Figure 1a. This model system includes QDs assembled in a two-dimensional hexagonally closed packed lattice.…”

Section: Model Of Energy Transfer In Quantum Dot Solidsmentioning

confidence: 99%

Perspective: Nonequilibrium dynamics of localized and delocalized excitons in colloidal quantum dot solids

Lee

Tisdale

Willard

2018

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Self-assembled quantum dot (QD) solids are a highly tunable class of materials with a wide range of applications in solid-state electronics and optoelectronic devices.In this perspective, we highlight how the presence of microscopic disorder in these materials can influence their macroscopic optoelectronic properties. Specifically, we consider the dynamics of excitons in energetically disordered QD solids using a theoretical model framework for both localized and delocalized excitonic regimes. In both cases, we emphasize the tendency of energetic disorder to promote nonequilibrium relaxation dynamics and discuss how the signatures of these nonequilibrium effects manifest in time-dependent spectral measurements. Moreover, we describe the connection between the microscopic dynamics of excitons within the material and the measurement of material specific parameters, such as emission linewidth broadening and energetic dissipation rate.

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Section: Model Of Energy Transfer In Quantum Dot Solidsmentioning

confidence: 99%

Perspective: Nonequilibrium dynamics of localized and delocalized excitons in colloidal quantum dot solids

Lee

Tisdale

Willard

2018

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…In addition, when the QDs are trapped into solid matrices, their performances, such as PL intensity and lifetime, usually decrease by 10–90% compared to those of QDs dispersed in liquid phases . The degradation of the QD performance has been attributed to i) surface defect generation, ii) interparticle aggregation, and iii) exciton quenching through Förster, Dexter, or tandem energy transfer processes . The dispersion of QDs in liquid phases is also incompatible with the form factors of various devices and is hardly free from liquid leaks.…”

Section: Fitting Parameters Of Time‐resolved Pl Decay Curves Of Greenmentioning

confidence: 99%

Highly Elastic and >200% Reversibly Stretchable Down‐Conversion White Light‐Emitting Diodes Based on Quantum Dot Gel Emitters

Choi

Kim

et al. 2020

Advanced Optical Materials

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electronics/optoelectronics, and artificial lighting technologies. [1] The advent of soft electronics has created a strong demand for the fabrication of highly flexible and stretchable WLEDs, [2] to support the development of advanced devices and systems with novel form factors. [3] In general, two main approaches, namely electroluminescence (EL) and photo luminescence (PL) or down-conversion, have been explored for fabricating white LEDs. [4] WLEDs based on EL have generated high expectations in the related research community in terms of efficiency and stability, and a few flexible light-emitting diodes (LEDs) have been reported. [5] However, the EL approach requires i) a multilayered structure design for transport/recombination of electrons and holes and ii) a complicated packaging process, which makes it hard to fabricate large-area devices in a cost-effective way. In particular, the multilayered structure contains interfaces of heterogeneous materials with different mechanical properties (e.g., elastic modulus and Poisson's ratio), which often result in mechanical failure under external stress. [3a,5a,6] On the other hand, down-conversion white LEDs have become increasingly popular in academic research and practical applications, due to their high performances and simple fabrication procedures. Owing to their high photostability, excellent color purity (with a narrow full width at half maximum, FWHM), high PL quantum yields (QYs, up to 100%), and color tunability from the ultraviolet to infrared region, semiconductor quantum dots (QDs) represent promising candidate materials for nextgeneration LEDs. [7] Various types of QDs encapsulated within solid matrices (e.g., silica particles, glass blocks, and polymer films) have been employed in down-conversion white LEDs, and high color rendering indexes (CRIs) and luminous efficacies (LEs) have been reported for LEDs based on InP/ZnS, carbon, perovskite, silicon, and cadmium-containing QDs. [8] However, owing to the poor mechanical reliability of the solid matrices, little progress has been made in developing stretchable down-conversion WLEDs using QDs. In addition, when the QDs are trapped into solid matrices, their performances, such as PL intensity and lifetime, usually decrease by 10-90% compared to those of QDs dispersed in liquid phases. [9] The Combining the characteristics of different materials offers exciting new opportunities for advanced applications in various fields. Herein, white lightemitting diodes (WLEDs) with >200% reversible stretchability are fabricated using six-color quantum dots (QDs) gel emitters. Stable aqueous-phase alloy core/shell QDs with high quantum yield are obtained via ligand exchange using a ternary solvent system. Transparent and highly stretchable gels with large pores are created by binary-solvent-based gelation at low temperatures. Importantly, the QDs and the gel originate from the same two solvents, which make the QDs highly compatible with the gelation process. Consequently, QDs of six different colors are incorpora...

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“…If there is strong overlap between the absorption and emission spectra of the QDs, the RET efficiency is high. The RET process can be minimized by band engineering through type‐II core/ shell or transition‐metal‐doped QDs, where the emission spectra are more red‐shifted relative to the absorption band . This RET process is further facilitated if there is a size deviation between the QDs, where smaller QDs transfer the energy to the larger particles.…”

Section: How Carrier Dynamics Can Benefit Qdscsmentioning

confidence: 99%

“…The RETp rocess can be minimized by band engineering through type-II core/ shell or transitionmetal-dopedQ Ds, where the emissions pectra are more redshifted relative to the absorption band. [11] This RETp rocess is furtherf acilitated if there is as ize deviation between the QDs, where smaller QDs transfer the energy to the larger particles. This energy transfer due to size deviation has also been used for light harvesting in the quantum-funnel solar cell developed by Kim et al Higher efficiency is achieved through excitonf unnelling due to RET between PbS QDs of different sizes.…”

Section: Energytransfer In Qds and Study Of Electron Transfer Betweenmentioning

confidence: 99%

Correlating Charge‐Carrier Dynamics with Efficiency in Quantum‐Dot Solar Cells: Can Excitonics Lead to Highly Efficient Devices?

Maiti

Dana

Ghosh

2018

Chemistry A European J

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The photovoltaic performance of quantum-dot solar cells strongly depends on the charge-carrier relaxation and recombination processes, which need to be modulated in a favorable way to obtain maximum efficiency. Recently, significant efforts have been devoted to investigate the carrier dynamics of nanocrystal sensitizers, both in solution and deposited on TiO photoanodes, with the aim to correlate the excitonics with solar-energy conversion efficiency. This Minireview summarizes some proof of the concepts that efficiency can be directly correlated to the exciton dynamics of quantum-dot solar cells. The presented findings are based on CdSeS alloy, CdSe/CdS core/shell, Au/CdSe nanohybrids, and Mn-doped CdZnSSe nanocrystals, where the favourable excitonic processes are optimized to enhance the efficiency. Future prospects and limitations are addressed as well.

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Energy Transfer in Quantum Dot Solids

Cited by 101 publications

References 46 publications

Perspective: Nonequilibrium dynamics of localized and delocalized excitons in colloidal quantum dot solids

Perspective: Nonequilibrium dynamics of localized and delocalized excitons in colloidal quantum dot solids

Highly Elastic and >200% Reversibly Stretchable Down‐Conversion White Light‐Emitting Diodes Based on Quantum Dot Gel Emitters

Correlating Charge‐Carrier Dynamics with Efficiency in Quantum‐Dot Solar Cells: Can Excitonics Lead to Highly Efficient Devices?

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