CdS/ZnS core–shell nanocrystal photosensitizers for visible to UV upconversion

Gray, Victor; Xia, Pan; Huang, Zhiyuan; Moses, Emily M; Fast, Alexander; Fishman, Dmitry A.; Vullev, Valentine I.; Abrahamsson, Maria; Moth‐Poulsen, Kasper; Tang, Ming Lee

doi:10.1039/c7sc01610g

Cited by 111 publications

(146 citation statements)

References 73 publications

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“…This enhancement is due to the suppression of hole transfer from PbS QD to 5‐CT by growth of CdS shell. However, the CdS shell slows down TET from 5.91±0.60 ns −1 in PbS// 5‐CT to 1.03±0.09 ns −1 in PbS/CdS// 5‐CT , consistent with the shell being a barrier for TET . Interestingly, the decay of the 5‐CT triplet state also slows down from 3.67±0.52 μs −1 in PbS// 5‐CT to 0.37±0.02 μs −1 in PbS/CdS// 5‐CT .…”

Section: Figurementioning

confidence: 99%

PbS/CdS Core–Shell Quantum Dots Suppress Charge Transfer and Enhance Triplet Transfer

Huang

Mahboub

et al. 2017

Angewandte Chemie

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As ub-monolayer CdS shell on PbS quantum dots (QDs) enhances triplet energy transfer (TET) by suppressing competitive charge transfer from QDs to molecules.T he CdS shell increases the linear photon upconversion quantum yield (QY) from 3.5 %f or PbS QDs to 5.0 %f or PbS/CdS QDs when functionalizedw ith at etracene acceptor, 5-CT.W hile transient absorption spectroscopyr eveals that both PbS and PbS/CdS QDs show the formation of the 5-CT triplet (with rates of 5.91 AE 0.60 ns À1 and 1.03 AE 0.09 ns À1 respectively), ultrafast hole transfer occurs only from PbS QDs to 5-CT. Although the CdS shell decreases the TET rate,i te nhances TET efficiency from 60.3 AE 6.1 %to71.8 AE 6.2 %bysuppressing hole transfer.F urthermore,t he CdS shell prolongs the lifetime of the 5-CT triplet and thus enhances TET from 5-CT to the rubrene emitter,further bolstering the upconverison QY.

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Section: Figurementioning

confidence: 99%

PbS/CdS Core–Shell Quantum Dots Suppress Charge Transfer and Enhance Triplet Transfer

Huang

Mahboub

et al. 2017

Angewandte Chemie

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“…If TTA-UC technology can be reliably extended to the ultraviolet (UV) region (o400 nm), it will become suitable for a broader range of applications, such as for hydrogen generation by water splitting using anatase titanium dioxide (a-TiO 2 ), which has a band gap of 3.2 eV (l gap B 385 nm). 41 Since the pioneering studies by Castellano and co-workers 42,43 and Merkel and Dinnocenzo, 44 there have been multiple reports [45][46][47][48][49][50][51][52] exploring UC of visible light to UV light (UV-UC). Here, the principle of TTA-UC is briefly described (Fig.…”

Section: Introductionmentioning

confidence: 99%

Visible-to-ultraviolet (<340 nm) photon upconversion by triplet–triplet annihilation in solvents

Murakami

Motooka

Enomoto

et al. 2020

Phys. Chem. Chem. Phys.

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“…Similarly, CdS−ZnS and PbS−CdS core−shell NCs were essential in achieving photon upconversion QYs of 5.2% and 8.4% for the production of UV and visible light, respectively. 30 With NC light absorbers, visible-to-UV upconversion is 5 times more efficient than with organic sensitizers, 30−32 while a relatively high NIR-to-visible upconversion QY of 8.4% was realized with an excitation intensity of 3.2 mW/cm 2 , approximately 3 times lower than the available solar flux.…”

Section: Current Status and Challengesmentioning

confidence: 99%

Designing Transmitter Ligands That Mediate Energy Transfer between Semiconductor Nanocrystals and Molecules

2017

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Molecular control of energy transfer is an attractive proposition because it allows chemists to synthetically tweak various kinetic and thermodynamic factors. In this Perspective, we examine energy transfer between semiconductor nanocrystals (NCs) and π-conjugated molecules, focusing on the transmitter ligand at the organic−inorganic interface. Efficient transfer of triplet excitons across this interface allows photons to be directed for effective use of the entire solar spectrum. For example, a photon upconversion system composed of semiconductor NCs as sensitizers, bound organic ligands as transmitters, and molecular annihilators has the advantage of large, tunable absorption cross sections across the visible and near-infrared wavelengths. This may allow the near-infrared photons to be harnessed for photovoltaics and photocatalysis. Here we summarize the progress in this recently reported hybrid upconversion platform and point out the challenges. Since triplet energy transfer (TET) from NC donors to molecular transmitters is one of the bottlenecks, emphasis is on the design of transmitters in terms of molecular energetics, photophysics, binding affinity, stability, and energy offsets with respect to the NC donor. Increasing the efficiency of TET in this hybrid platform will increase both the up-and down-conversion quantum yields, potentially exceeding the Shockley−Queisser limit for photovoltaics and photocatalysis.

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CdS/ZnS core–shell nanocrystal photosensitizers for visible to UV upconversion

Abstract: Herein we report the first example of nanocrystal (NC) sensitized triplet–triplet annihilation based photon upconversion from the visible to ultraviolet (vis-to-UV).

Cited by 111 publications

References 73 publications

PbS/CdS Core–Shell Quantum Dots Suppress Charge Transfer and Enhance Triplet Transfer

PbS/CdS Core–Shell Quantum Dots Suppress Charge Transfer and Enhance Triplet Transfer

Visible-to-ultraviolet (<340 nm) photon upconversion by triplet–triplet annihilation in solvents

Designing Transmitter Ligands That Mediate Energy Transfer between Semiconductor Nanocrystals and Molecules

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