Dynamics of spontaneous emission of quantum dots in a one-dimensional cholesteric liquid crystal photonic cavity

Rodarte, Andrea L.; Shcherbatyuk, Georgiy; Shcherbatyuk, Laurel; Hirst, Linda S.; Ghosh, Sayantani

doi:10.1039/c2ra21167j

Cited by 23 publications

(19 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When the devices shown in Figure 3 were excited with the 532 nm continuous wave laser, we observed characteristic emission for QDs coupling with the cholesteric cavity for both types of particle (Figure 3e,f). The results are consistent with recent reported data from our group for ODA-QDs only [19,20]. In the ODA-QD device we observed that good cavity coupling as shown in Figure 3e as an example was very location dependent.…”

Section: Resultssupporting

confidence: 83%

Quantum Dot/Liquid Crystal Nanocomposites in Photonic Devices

et al. 2015

Self Cite

View full text Add to dashboard Cite

Quantum dot/liquid crystal nano-composites are promising new materials for a variety of applications in energy harvesting, displays and photonics including the liquid crystal laser. To realize many applications, however, we need to control and stabilize nano-particle dispersion in different liquid crystal host phases and understand how the particles behave in an anisotropic fluid. An ideal system will allow for the controlled assembly of either well-defined nano-particle clusters or a uniform particle distribution. In this paper, we investigate mesogen-functionalized quantum dots for dispersion in cholesteric liquid crystal. These nanoparticles are known to assemble into dense stable packings in the nematic phase, and such structures, when localized in the liquid crystal defects, can potentially enhance the coupling between particles and a cholesteric cavity. Controlling the dispersion and assembly of quantum dots using mesogenic surface ligands, we demonstrate how resonant fluid photonic cavities can result from the co-assembly of luminescent nanoparticles in the presence of cholesteric liquid crystalline ordering.

show abstract

Section: Resultssupporting

confidence: 83%

Quantum Dot/Liquid Crystal Nanocomposites in Photonic Devices

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…This technique, applied previously by our group, [29][30][31] produces PL intensity maps of a 1 mm thick slice combined with emission spectra for each pixel recorded. PL microscopy provides a unique method for characterizing the distribution of fluorescent particles in liquid crystals, as energy-transfer processes, such as Forster resonance energy transfer (FRET), can be detected.…”

Section: Quantum-dot Organization In the Isotropic And Nematic Phasesmentioning

confidence: 99%

“…In cholesteric devices, embedded QDs can act as emitters coupled to a tunable fluid cavity, producing applications such as the quantum dot liquid crystal laser [32] and switchable cavities able to spatially modulate QD emission. [29,31] The efficiency of such devices will depend on our control of co-operative effects between adjacent particles. For example energy transfer processes such as FRET can reduce the efficiency of QD cavity coupling if the particles are closely packed in aggregates.…”

Section: Performance In Soft Photonic Devicesmentioning

confidence: 99%

Tuning Quantum‐Dot Organization in Liquid Crystals for Robust Photonic Applications

et al. 2014

Self Cite

View full text Add to dashboard Cite

Mesogenic ligands have the potential to provide control over the dispersion and stabilization of nanoparticles in liquid crystal (LC) phases. The creation of such hybrid materials is an important goal for the creation of soft tunable photonic devices, such as the LC laser. Herein, we present a comparison of isotropic and mesogenic ligands attached to the surface of CdSe (core‐only) and CdSe/ZnS (core/shell) quantum dots (QDs). The mesogenic ligand′s flexible arm structure enhances ligand alignment, with the local LC director promoting QD dispersion in the isotropic and nematic phases. To characterize QD dispersion on different length scales, we apply fluorescence microscopy, X‐ray scattering, and scanning confocal photoluminescent imaging. These combined techniques demonstrate that the LC‐modified QDs do not aggregate into the dense clusters observed for dots with simple isotropic ligands when dispersed in liquid crystal, but loosely associate in a fluid‐like droplet with an average interparticle spacing >10 nm. Embedding the QDs in a cholesteric cavity, we observe comparable coupling effects to those reported for more closely packed isotropic ligands.

show abstract

“…For this purpose, LC mixture consisting of ≈ 10% of mesogenic diacrylate, ≈ 15% of LC monoacrylate, ≈ 75% of lowmolar-mass LCs and 1%-2% of photoinitiator (see Table 1 ) is placed into asymmetrical cell with two glass substrates coated by different polymer layers -polyvinyl alcohol (PVA) and polyvinyl-cinnamate (PVCin). [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Cholesteric liquid crystals doped with QDs present a special interest because the photonic bandgap structure of cholesteric media when combined with emission properties of QDs provides the opportunity to realize a variety of specifi c photooptical properties. UV irradiation of these cells leads to photopolymerization of acrylates.…”

mentioning

confidence: 99%

“…UV irradiation of these cells leads to photopolymerization of acrylates. [16][17][18] For example, in recent publication, [ 16 ] the modulation of recombination lifetimes of CdSe/ZnS QDs (0.01-0.02 wt%) dispersed in cholesteric low-molar-mass liquid crystal and time-resolved emission from QD ensembles in LC matrices with different alignment were investigated. The LC fi lm obtained after photo polymerization has microheterogeneous structure consisting of LC polymer network and low-molarmass LC microphase.…”

mentioning

confidence: 99%

An Effective Method for the Preparation of Stable LC Composites with High Concentration of Quantum Dots

Bobrovsky

Samokhvalov

Shibaev

2014

Advanced Optical Materials

View full text Add to dashboard Cite

COMMUNICATION modifi cation of QDs with complex mesogen containing ligands, which resulted in the preparation of thermodynamically stable QDs solution in LC matrix, yet with still low concentration of the additive (0.25%). In the most of other papers devoted to QDs solutions in LC media the concentration of QDs does not exceed 0.1%.There are several recent works concerning the LC-QDs mixtures with higher concentration of the QDs. [ 21,22 ] Yet, these experimental results are in strong contradiction with other publications devoted to the similar mixtures and lack strong experimental proofs of the thermodynamic stability of these composites.In most cases, the methods of preparation of QD-LC composites are based on simple mixing of components in common solvent followed by spin coating or drying. [ 23,24 ] In some cases, bi-or multilayer fi lms containing QDs-rich layers were prepared by sequential spin-coating method. [ 25,26 ] As a resume, from the literature data, we may conclude that the development of new methods for embedding of high amount of QDs in LC media without the loss in the optical properties of any of the component is still challenging and highly relevant. In the present paper, we propose a new method of preparation of stable QD-LC composites containing very high (up to 10 wt%) amount of QDs.The idea of the elaborated procedure is schematically depicted in Figure 1 . On the fi rst stage, the polymer-stabilized LC fi lm (with any type of LC phase) is prepared (Figure 1 a). For this purpose, LC mixture consisting of ≈ 10% of mesogenic diacrylate, ≈ 15% of LC monoacrylate, ≈ 75% of lowmolar-mass LCs and 1%-2% of photoinitiator (see Table 1 ) is placed into asymmetrical cell with two glass substrates coated by different polymer layers -polyvinyl alcohol (PVA) and polyvinyl-cinnamate (PVCin). Rubbing of the substrates with polymer layers allows one to achieve uniaxial orientation of LCs molecules. UV irradiation of these cells leads to photopolymerization of acrylates. The presence of reactive C C double bonds in the cinnamate fragment of PVCin warrants a good adhesion of polymer network to PVCin-coated glass substrate, which makes mechanical removal of the PVA-coated glass plate (Figure 1 b) on the next stage more easy. The LC fi lm obtained after photo polymerization has microheterogeneous structure consisting of LC polymer network and low-molarmass LC microphase. Nevertheless, under appropriate irradiation conditions (light intensity, monomers, and photoinitiator structure and their concentration), characteristic dimensions of these microphases are comparable or even smaller than the wavelength of visible light, which minimizes light scattering of LC-composite fi lms. [ 20,21 ] LC-polymer network stabilizes the alignment of the LCs molecules, and has the possibility Organic-inorganic hybrid materials, in particular, liquid crystals doped with nanoparticles, quantum dots (QDs) and other nanometer-scale colloid particles attract a great attention of large number of research groups due to their unique opti...

show abstract

Dynamics of spontaneous emission of quantum dots in a one-dimensional cholesteric liquid crystal photonic cavity

Cited by 23 publications

References 26 publications

Quantum Dot/Liquid Crystal Nanocomposites in Photonic Devices

Quantum Dot/Liquid Crystal Nanocomposites in Photonic Devices

Tuning Quantum‐Dot Organization in Liquid Crystals for Robust Photonic Applications

An Effective Method for the Preparation of Stable LC Composites with High Concentration of Quantum Dots

Contact Info

Product

Resources

About