Journal Article

FZJ-2020-03828

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Simultaneous Photonic and Excitonic Coupling in Spherical Quantum Dot Supercrystals

Marino, E. ; Sciortino, A. ; Berkhout, A. ; MacArthur, K. E.FZJ* ; Heggen, M.FZJ* ; Gregorkiewicz, T. ; Kodger, T. E. ; Capretti, A. ; Murray, C. B. ; Koenderink, A. F. ; Messina, F. ; Schall, P. (Corresponding author)

2020
Soc. Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/26032  doi:10.1021/acsnano.0c06188

Abstract: 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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Contributing Institute(s):

1. Physik Nanoskaliger Systeme (ER-C-1)

Research Program(s):

1. 143 - Controlling Configuration-Based Phenomena (POF3-143) (POF3-143)

Appears in the scientific report 2020

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF >= 10 ; JCR ; NCBI Molecular Biology Database ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Web of Science Core Collection

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