Alloyed heterostructures of CdSexS1-x nanoplatelets with highly tunable optical gain performance

Date
2017
Advisor
Instructor
Source Title
Chemistry of Materials
Print ISSN
0897-4756
Electronic ISSN
Publisher
American Chemical Society
Volume
29
Issue
11
Pages
4857 - 4865
Language
English
Type
Article
Journal Title
Journal ISSN
Volume Title
Abstract

Here, we designed and synthesized alloyed heterostructures of CdSexS1-x nanoplatelets (NPLs) using CdS coating in the lateral and vertical directions for the achievement of highly tunable optical gain performance. By using homogeneously alloyed CdSexS1-x core NPLs as a seed, we prepared CdSexS1-x/CdS core/crown NPLs, where CdS crown region is extended only in the lateral direction. With the sidewall passivation around inner CdSexS1-x cores, we achieved enhanced photoluminescence quantum yield (PL-QY) (reaching 60%), together with increased absorption cross-section and improved stability without changing the emission spectrum of CdSexS1-x alloyed core NPLs. In addition, we further extended the spectral tunability of these solution-processed NPLs with the synthesis of CdSexS1-x/CdS core/shell NPLs. Depending on the sulfur composition of the CdSexS1-x core and thickness of the CdS shell, CdSexS1-x/CdS core/shell NPLs possessed highly tunable emission characteristics within the spectral range of 560-650 nm. Finally, we studied the optical gain performances of different heterostructures of CdSexS1-x alloyed NPLs offering great advantages, including reduced reabsorption and spectrally tunable optical gain range. Despite their decreased PL-QY and reduced absorption cross-section upon increasing the sulfur composition, CdSexS1-x based NPLs exhibit highly tunable amplified spontaneous emission performance together with low gain thresholds down to ∼53 μJ/cm2.

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Book Title
Keywords
Absorption spectroscopy, Cadmium sulfide, Emission spectroscopy, Sulfur, Absorption cross sections, Amplified spontaneous emissions, Emission spectrums, Photoluminescence quantum yields, Sidewall passivation, Spectral tunability, Spectrally tunable, Vertical direction, Optical gain
Citation
Published Version (Please cite this version)