Effect of Core/Shell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe/CdS Nanocrystals
| Autor: | Sergio Brovelli, Iwan Moreels, Wan Ki Bae, Valerio Pinchetti, Victor I. Klimov, Sotirios Christodoulou, Margherita Zavelani-Rossi, Andrea Camellini, Gianluca Sirigu, Liberato Manna, Francesco Meinardi, Francesco De Donato |
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| Přispěvatelé: | Pinchetti, V, Meinardi, F, Camellini, A, Sirigu, G, Christodoulou, S, Bae, W, De Donato, F, Manna, L, Zavelani Rossi, M, Moreels, I, Klimov, V, Brovelli, S |
| Jazyk: | angličtina |
| Rok vydání: | 2016 |
| Předmět: |
Materials science
Interface (computing) core/shell heterostructure Shell (structure) amplified spontaneous emission core/shell heterostructures dual emission exciton dynamics interface structure nanocrystal quantum dots Engineering (all) Materials Science (all) Physics and Astronomy (all) General Physics and Astronomy Nanotechnology 02 engineering and technology Crystal structure 010402 general chemistry 01 natural sciences Condensed Matter::Materials Science Colloid General Materials Science nanocrystal quantum dot business.industry General Engineering Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 0104 chemical sciences Core (optical fiber) Nanocrystal Photonics exciton dynamic 0210 nano-technology business Dual color |
| Zdroj: | ACS nano 10 (2016): 6877–6887. doi:10.1021/acsnano.6b02635 info:cnr-pdr/source/autori:Pinchetti, Valerio; Meinardi, Francesco; Camellini, Andrea; Sirigu, Gianluca; Christodoulou, Sotirios; Bae, Wan Ki; De Donato, Francesco; Manna, Liberato; Zavelani-Rossi, Margherita; Moreels, Iwan; Klimov, Victor I.; Brovelli, Sergio/titolo:Effect of Core%2FShell Interface on Carrier Dynamics and Optical Gain Properties of Dual-Color Emitting CdSe%2FCdS Nanocrystals/doi:10.1021%2Facsnano.6b02635/rivista:ACS nano/anno:2016/pagina_da:6877/pagina_a:6887/intervallo_pagine:6877–6887/volume:10 |
| Popis: | Two-color emitting colloidal semiconductor nanocrystals (NCs) are of interest for applications in multimodal imaging, sensing, lighting, and integrated photonics. Dual color emission from core- and shell-related optical transitions has been recently obtained using so-called dot-in-bulk (DiB) CdSe/CdS NCs comprising a quantum-confined CdSe core embedded into an ultrathick (similar to 7-9 nm) CdS shell. The physical mechanism underlying this behavior is still under debate. While a large shell volume appears to be a necessary condition for dual emission, comparison between various types of thick-shell CdSe/CdS NCs indicates a critical role of the interface "sharpness" and the presence of potential barriers. To elucidate the effect of the interface morphology on the dual emission, we perform side-by-side studies of CdSe/CdS DiB-NCs with nominally identical core and shell dimensions but different structural properties of the core/shell interface arising from the crystal structure of the starting CdSe cores (zincblende vs wurtzite). While both structures exhibit dual emission under comparable pump intensities, NCs with a zincblende core show a faster growth of shell luminescence with excitation fluence and a more readily realized regime of amplified spontaneous emission (ASE) even under "slow" nanosecond excitation. These distinctions can be linked to the structure of the core/shell interface: NCs grown from the zincblende cores contain a similar to 3.5 nm thick zincblende CdS interlayer, which separates the core from the wurtzite CdS shell and creates a potential barrier for photoexcited shell holes inhibiting their relaxation into the core. This helps maintain a higher population of shell states and simplifies the realization of dual emission and ASE involving shell-based optical transitions. |
| Databáze: | OpenAIRE |
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