Lasing Supraparticles Self-Assembled from Nanocrystals

Montanarella, Federico; Urbonas, Darius; Chadwick, Luke; Moerman, Pepijn G.; Baesjou, Patrick J.; Mahrt, Rainer F.; Blaaderen, Alfons van; Stöferle, Thilo; Vanmaekelbergh, Daniël

doi:10.1021/acsnano.8b07896

Cited by 63 publications

(100 citation statements)

References 45 publications

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“…Previous work has focused on using supraparticles as spherical resonators to manipulate light emission properties toward lasing applications. 19 , 31 , 32 Here instead, we investigate the potential of these spherical QD SCs as light-harvesting structures with light absorption properties intrinsically tailored through size. We provide a quantitative approach by using Mie theory that describes the interaction of light with a dielectric sphere.…”

Section: Resultsmentioning

confidence: 99%

Simultaneous Photonic and Excitonic Coupling in Spherical Quantum Dot Supercrystals

et al. 2020

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Semiconductor nanocrystals, or quantum dots (QDs), simultaneously benefit from inexpensive low-temperature solution processing and exciting photophysics, making them the ideal candidates for next-generation solar cells and photodetectors. While the working principles of these devices rely on light absorption, QDs intrinsically belong to the Rayleigh regime and display optical behavior limited to electric dipole resonances, resulting in low absorption efficiencies. Increasing the absorption efficiency of QDs, together with their electronic and excitonic coupling to enhance charge carrier mobility, is therefore of critical importance to enable practical applications. Here, we demonstrate a general and scalable approach to increase both light absorption and excitonic coupling of QDs by fabricating hierarchical metamaterials. We assemble QDs into crystalline supraparticles using an emulsion template and demonstrate that these colloidal supercrystals (SCs) exhibit extended resonant optical behavior resulting in an enhancement in absorption efficiency in the visible range of more than 2 orders of magnitude with respect to the case of dispersed QDs. This successful light trapping strategy is complemented by the enhanced excitonic coupling observed in ligand-exchanged SCs, experimentally demonstrated through ultrafast transient absorption spectroscopy and leading to the formation of a free biexciton system on sub-picosecond time scales. These results introduce a colloidal metamaterial designed by self-assembly from the bottom up, simultaneously featuring a combination of nanoscale and mesoscale properties leading to simultaneous photonic and excitonic coupling, therefore presenting the nanocrystal analogue of supramolecular structures.

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Section: Resultsmentioning

confidence: 99%

Simultaneous Photonic and Excitonic Coupling in Spherical Quantum Dot Supercrystals

et al. 2020

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“…To image the 1.93 μm CSLBs we used a flow cell produced as detailed in the Supplementary Material of Montanarella et al [49] As the base of our flow cell we used a single capillary with dimensions 3 cm × 2 mm × 200 μm. To prevent the lipid coated clusters from sticking to the class capillary, we coated the inside of the capillary with poly(2-hydroxyethyl acrylate) (pHEA) polymers.…”

Section: A Experimentsmentioning

confidence: 99%

Flexibility-induced effects in the Brownian motion of colloidal trimers

Verweij

Moerman

Ligthart

et al. 2020

Phys. Rev. Research

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Shape changes resulting from segmental flexibility are ubiquitous in molecular and biological systems, and are expected to affect both the diffusive motion and (biological) function of dispersed objects. The recent development of colloidal structures with freely jointed bonds have now made a direct experimental investigation of diffusive shape-changing objects possible. Here, we show the effect of segmental flexibility on the simplest possible model system, a freely jointed cluster of three spherical particles, and validate long-standing theoretical predictions. We find that, in addition to the rotational diffusion time, an analogous conformational diffusion time governs the relaxation of the diffusive motion, unique to flexible assemblies, and that their translational diffusivity differs by a small but measurable amount. We also uncovered a Brownian quasiscallop mode, where diffusive motion is coupled to Brownian shape changes. Our findings could have implications for molecular and biological systems where diffusion plays an important role, such as functional site availability in lock-and-key protein interactions.

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“…Samples consist of ~8–10 g of PbS NCs synthesized using an upscaled approach 26 and condensed into a powder of NC superlattice crystallites with a solution-based ligand exchange (Supplementary Note 2) 25 . While the large sample sizes required for INS prevents us from employing state-of-the-art superlattice formation procedures 1–4 , our calculations indicate that superlattice phonons will still be observed in a disordered system (Fig. 2d).…”

Section: Resultsmentioning

confidence: 83%

Nanocrystal superlattices as phonon-engineered solids and acoustic metamaterials

et al. 2019

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Phonon engineering of solids enables the creation of materials with tailored heat-transfer properties, controlled elastic and acoustic vibration propagation, and custom phonon–electron and phonon–photon interactions. These can be leveraged for energy transport, harvesting, or isolation applications and in the creation of novel phonon-based devices, including photoacoustic systems and phonon-communication networks. Here we introduce nanocrystal superlattices as a platform for phonon engineering. Using a combination of inelastic neutron scattering and modeling, we characterize superlattice-phonons in assemblies of colloidal nanocrystals and demonstrate that they can be systematically engineered by tailoring the constituent nanocrystals, their surfaces, and the topology of superlattice. This highlights that phonon engineering can be effectively carried out within nanocrystal-based devices to enhance functionality, and that solution processed nanocrystal assemblies hold promise not only as engineered electronic and optical materials, but also as functional metamaterials with phonon energy and length scales that are unreachable by traditional architectures.

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Lasing Supraparticles Self-Assembled from Nanocrystals

Cited by 63 publications

References 45 publications

Simultaneous Photonic and Excitonic Coupling in Spherical Quantum Dot Supercrystals

Simultaneous Photonic and Excitonic Coupling in Spherical Quantum Dot Supercrystals

Flexibility-induced effects in the Brownian motion of colloidal trimers

Nanocrystal superlattices as phonon-engineered solids and acoustic metamaterials

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