Influence of single dye molecules on temperature and time dependent optical properties of CdSe/ZnS quantum dots: Ensemble and single nanoassembly detection

Zenkevich, É. I.; Stupak, A. P.; Kowerko, Danny; Borczyskowski, Christian von

doi:10.1016/j.chemphys.2012.02.008

Cited by 44 publications

(36 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Correspondingly, due to different thermal expansion coefficients for the semi-rigid capping layer and the ZnS shell as well as possible strain effects, slight changes of electron delocalization may take place in the range of the phase transition. In this respect, we believe that slightly different "kink" temperatures for the first excitonic absorption band (∼218 K) and the PL band (∼223 K) for TOPO-capped CdSe/ZnS QDs, may be explained by the different nature of the corresponding transitions in absorption (allowed excitonic ones [55] ) and in emission (trap dominated at low T).…”

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

confidence: 99%

“…We have shown for the first time [55] that, in addition to PL, the QD band-edge absorption is obviously also sensitive to such a phase transition of the surfactant capping layer at temperatures close to ∼218 K. When discussing the appearance of the "kink", one has to take into account that for TOPO-or amine-capped CdSe/ZnS QDs, a phase transition of the capping ligand layer at low T may cause some straininduced deformation of the ZnS shell. The reason of that is that according to [88,89] absorption and PL of core-shell CdSe/ ZnS QDs are red-shifted with respect to merely core QDs because in the former case the electron wave function tunnels into the shell, increasing the delocalization of the electronhole pair, lowering the confinement energy and consequently the energy of the excited state.…”

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

confidence: 99%

“…Using this approach, it was found that the estimated values of complexation constant K C for "QD-Porphyrin" nanocomposites lie in the region from ∼10 5 M -1 (for H 2 P(m-Pyr) 1 ) to ∼10 7 M -1 (for H 2 P(m-Pyr) 4 ). [50,55,76] The details of this approach including also the analysis of time resolved kinetics of QD PL decays will be presented in the forthcoming paper.…”

Section: Comparative Titration Experiments and Nanocomposite Formationmentioning

confidence: 99%

“…The temporal variation of trap and near band edge states have been studied with a diimide dye using ensemble and single object detection. We will show that the combination of bulk and single molecule/single particle experiments [51,52,55] is a tool to precisely identify the interaction of exactly one QD with one dye molecule leading to a microscopic understanding of the formation (including ligand dynamics) and related mechanisms of PL quenching dynamics for "QD-Dye" nanocomposite nanoassemblies.…”

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

confidence: 99%

“…[31][32][33][34][35][36][37][38] Inspired by our earlier work on self-assembled multiporphyrin arrays [39][40][41][42][43][44][45] we have elaborated the experimental approach in the direct labelling of trioctylphosphine oxide (TOPO)-and amino (AM) -capped semiconductor quantum dots (QD) CdSe/ZnS with functional ligands (dyes) of two types (pyridyl substituted porphyrins and heterocyclic pyridyl functionalized perylene diimide molecules) in liquid solutions and polymeric matrixes. [46][47][48][49][50][51][52][53][54][55] We have shown that depending on redox and electronic properties of interacting subunits as well as anchoring groups (connecting organic and inorganic counterparts) the formation of "QD-Dye" nanocomposites allows for a controlled realization of mutually relative (spatial) orientations and electronic energy scales in order to optimize intended photoinduced processes such as charge transfer, [56,57] fluorescence Foerster energy transfer (FRET) [20,46,47,50,52] or electron tunnelling in the conditions of quantum confinement (non-FRET process). [48,50,53] Typically, all these processes lead to the pronounced quenching of QD photoluminescence (PL) in nanocomposites that may be used as an indicator of complex interface phenomena selectively depending on attached ligands (porphyrins, perylene diimides, etc.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

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

Self Cite

View full text Add to dashboard Cite

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

show abstract

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

confidence: 99%

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

confidence: 99%

Section: Comparative Titration Experiments and Nanocomposite Formationmentioning

confidence: 99%

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

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

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

Self Cite

View full text Add to dashboard Cite

show abstract

Molecular Gelation‐Induced Functional Phase Separation in Polymer Film for Energy Transfer Spectral Conversion

Jintoku

Yamaguchi

Takafuji

et al. 2014

Adv Funct Materials

View full text Add to dashboard Cite

4105www.MaterialsViews.com wileyonlinelibrary.com even plants cannot use UV wavelengths for photosynthesis), [ 2 ] but also strong UV light causes the solar cell to gradually deteriorate; one reasonable solution in overcoming this challenge is to pursue spectral conversion from the visible bands rather than direct UV conversion. Spectral conversion technology is the best-known candidate for this task. Therefore, several types of spectral conversion materials have been developed, which contain various fl uorescent materials, including monomeric and polymeric dyes, [ 3 ] organometallic complexes, [ 4 ] and quantum dots.[ 5 ] However, spectral conversion fi lms (SCFs) still have several disadvantages, such as low conversion effi ciency, high fabrication cost, and poor durability.Herein, we propose a new strategy for spectral conversion through effi cient energy transfer in a phase-separated nanosized functional domain. Our approach can be defi ned as utilization of a highly oriented nano-sized phase separation in a polymer matrix using a low-molecular gelation technique. [ 6 ] The nano-sized domain is induced by using self-assembling of organogelators as monomer components that can form one-dimensional fi ber-like aggregates through intermolecular hydrogen bonding in a polymer matrix ( Figure 1 ). [ 7 ] This method has several advantages in the fabrication of SCF materials: 1) the produced polymer fi lm is transparent because our method does not generate macro-scale domains in the fi lm, which cause light scattering, but instead forms nanofi brillar aggregates; 2) self-assembling phase separation is accompanied by molecular concentration and fl uorescent group orientation, which promotes excimer formation and fl uorescence resonance energy transfer (FRET) processes; 3) tunability of the fl uorescent spectral band can be accomplished by a sol-to-gel transition.We chose the L -glutamide derivative [ 8 ] for the purposes of fabricating this system, as such species have good dispersity in a variety of solvents, suffi cient miscibility with polymeric materials, [ 9 ] and considerably low critical aggregation concentrations. Furthermore, their gelation properties and fl uorescence behaviors in organic media have been extensively investigated by doping L -glutamide derivatives with fl uorescent groups such as pyrene, [ 10 ] thiophene, [ 11 ] and porphyrin. [ 12 ] In this study, we have prepared the L -glutamide-functionalized pyrene ( g -Pyr ) for use as the low-molecular-weight organogelator and fl uorescent dyes (Coumarin 6, Rubrene and Nile red) as the energy acceptor for FRET. Molecular Gelation-Induced Functional Phase Separation in Polymer Film for Energy Transfer Spectral ConversionHirokuni Jintoku , Miho Yamaguchi , Makoto Takafuji , and Hirotaka Ihara * A new strategy for creating the energy transfer spectral conversion thin fi lm by using fl uorophore-functionalized molecular gelation is proposed. This is based on the facts that nanofi brillar phase separation of the self-assembling pyrene derivative as a ...

show abstract

Formation Principles and Exciton Relaxation in Semiconductor Quantum Dot–Dye Nanoassemblies

Borczyskowski

Zenkevich

2013

Lecture Notes in Nanoscale Science and Technology

View full text Add to dashboard Cite

Influence of single dye molecules on temperature and time dependent optical properties of CdSe/ZnS quantum dots: Ensemble and single nanoassembly detection

Cited by 44 publications

References 56 publications

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

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

Molecular Gelation‐Induced Functional Phase Separation in Polymer Film for Energy Transfer Spectral Conversion

Formation Principles and Exciton Relaxation in Semiconductor Quantum Dot–Dye Nanoassemblies

Contact Info

Product

Resources

About