scholarly journals Size-Dependent Biexciton Quantum Yields and Carrier Dynamics of Quasi-Two-Dimensional Core/Shell Nanoplatelets

ACS Nano ◽  
2017 ◽  
Vol 11 (9) ◽  
pp. 9119-9127 ◽  
Author(s):  
Xuedan Ma ◽  
Benjamin T. Diroll ◽  
Wooje Cho ◽  
Igor Fedin ◽  
Richard D. Schaller ◽  
...  
Keyword(s):  
Carrier Dynamics ◽  
Quantum Yields ◽  
Core Shell ◽  
Two Dimensional ◽  
Size Dependent

Tunable nonlinear optical responses and carrier dynamics of two-dimensional antimonene nanosheets

2020 ◽  
Vol 5 (10) ◽  
pp. 1420-1429 ◽  
Author(s):  
Lei Zhang ◽  
Shah Fahad ◽  
Hao-Ran Wu ◽  
Tao-Tao Dong ◽  
Zi-Zhen Chen ◽  
...  
Keyword(s):  
Nonlinear Optical ◽  
Strong Influence ◽  
Optical Response ◽  
Carrier Dynamics ◽  
Nonlinear Optical Response ◽  
Two Dimensional ◽  
Size Dependent ◽  
Optical Responses ◽  
Size Controlled

We developed a size-controlled intercalation method to prepare Sb nanosheets. A distinct size-dependent nonlinear optical response, unveiling the strong influence of the scale of the Sb nanosheets on the carrier dynamics was observed.

High-Temperature Synthesis of CdSe-Based Core/Shell, Core/Shell/Shell, and Core/Graded-Shell Nanoplatelets for Stable and Efficient Narrowband Emitters

2019 ◽  
Author(s):  
Aurelio A. Rossinelli ◽  
Henar Rojo ◽  
Aniket S. Mule ◽  
Marianne Aellen ◽  
Ario Cocina ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Temperature ◽  
Equilibrium Shape ◽  
Size Variation ◽  
Crystal Defects ◽  
Atomic Scale ◽  
Quantum Yields ◽  
Core Shell ◽  
Compositional Gradient ◽  
High Quality

<div>Colloidal semiconductor nanoplatelets exhibit exceptionally narrow photoluminescence spectra. This occurs because samples can be synthesized in which all nanoplatelets share the same atomic-scale thickness. As this dimension sets the emission wavelength, inhomogeneous linewidth broadening due to size variation, which is always present in samples of quasi-spherical nanocrystals (quantum dots), is essentially eliminated. Nanoplatelets thus offer improved, spectrally pure emitters for various applications. Unfortunately, due to their non-equilibrium shape, nanoplatelets also suffer from low photo-, chemical, and thermal stability, which limits their use. Moreover, their poor stability hampers the development of efficient synthesis protocols for adding high-quality protective inorganic shells, which are well known to improve the performance of quantum dots. <br></div><div>Herein, we report a general synthesis approach to highly emissive and stable core/shell nanoplatelets with various shell compositions, including CdSe/ZnS, CdSe/CdS/ZnS, CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S, and CdSe/ZnSe. Motivated by previous work on quantum dots, we find that slow, high-temperature growth of shells containing a compositional gradient reduces strain-induced crystal defects and minimizes the emission linewidth while maintaining good surface passivation and nanocrystal uniformity. Indeed, our best core/shell nanoplatelets (CdSe/Cd<sub>x</sub>Zn<sub>1–x</sub>S) show photoluminescence quantum yields of 90% with linewidths as low as 56 meV (19.5 nm at 655 nm). To confirm the high quality of our different core/shell nanoplatelets for a specific application, we demonstrate their use as gain media in low-threshold ring lasers. More generally, the ability of our synthesis protocol to engineer high-quality shells can help further improve nanoplatelets for optoelectronic devices.</div>

Symmetry Breaking and the Turn-On Fluorescence of Small, Highly Strained Carbon Nanohoops

2019 ◽  
Author(s):  
Terri Lovell ◽  
Curtis Colwell ◽  
Lev N. Zakharov ◽  
Ramesh Jasti
Keyword(s):  
Symmetry Breaking ◽  
Theoretical Work ◽  
P Systems ◽  
Quantum Yields ◽  
Size Dependent ◽  
New Class ◽  
Carbon Carbon Bond ◽  
Conjugated Macrocycles ◽  
Structural Manipulation ◽  
Highly Strained

<p>[<i>n</i>]Cycloparaphenylenes, or “carbon nanohoops,” are unique conjugated macrocycles with radially oriented p-systems similar to those in carbon nanotubes. The centrosymmetric nature and conformational rigidity of these molecules lead to unusual size-dependent photophysical characteristics. To investigate these effects further and expand the family of possible structures, a new class of related carbon nanohoops with broken symmetry is disclosed. In these structures, referred to as <i>meta</i>[<i>n</i>]cycloparaphenylenes, a single carbon-carbon bond is shifted by one position in order to break the centrosymmetric nature of the parent [<i>n</i>]cycloparaphenylenes. Advantageously, the symmetry breaking leads to bright emission in the smaller nanohoops, which are typically non-fluorescent due to optical selection rules. Moreover, this simple structural manipulation retains one of the most unique features of the nanohoop structures-size dependent emissive properties with relatively large extinction coefficents and quantum yields. Inspired by earlier theoretical work by Tretiak and co-workers, this joint synthetic, photophysical, and theoretical study provides further design principles to manipulate the optical properties of this growing class of molecules with radially oriented p-systems.</p>

Symmetry Breaking and the Turn-On Fluorescence of Small, Highly Strained Carbon Nanohoops

2019 ◽  
Author(s):  
Terri Lovell ◽  
Curtis Colwell ◽  
Lev N. Zakharov ◽  
Ramesh Jasti
Keyword(s):  
Symmetry Breaking ◽  
Theoretical Work ◽  
P Systems ◽  
Quantum Yields ◽  
Size Dependent ◽  
New Class ◽  
Carbon Carbon Bond ◽  
Conjugated Macrocycles ◽  
Structural Manipulation ◽  
Highly Strained

<p>[<i>n</i>]Cycloparaphenylenes, or “carbon nanohoops,” are unique conjugated macrocycles with radially oriented p-systems similar to those in carbon nanotubes. The centrosymmetric nature and conformational rigidity of these molecules lead to unusual size-dependent photophysical characteristics. To investigate these effects further and expand the family of possible structures, a new class of related carbon nanohoops with broken symmetry is disclosed. In these structures, referred to as <i>meta</i>[<i>n</i>]cycloparaphenylenes, a single carbon-carbon bond is shifted by one position in order to break the centrosymmetric nature of the parent [<i>n</i>]cycloparaphenylenes. Advantageously, the symmetry breaking leads to bright emission in the smaller nanohoops, which are typically non-fluorescent due to optical selection rules. Moreover, this simple structural manipulation retains one of the most unique features of the nanohoop structures-size dependent emissive properties with relatively large extinction coefficents and quantum yields. Inspired by earlier theoretical work by Tretiak and co-workers, this joint synthetic, photophysical, and theoretical study provides further design principles to manipulate the optical properties of this growing class of molecules with radially oriented p-systems.</p>

Size-Dependent Separation of Colloidal Particles In Two-Dimensional Convective Self-Assembly

Langmuir ◽  
1995 ◽  
Vol 11 (8) ◽  
pp. 2975-2978 ◽  
Author(s):  
Mariko Yamaki ◽  
Junichi Higo ◽  
Kuniaki Nagayama
Keyword(s):  
Self Assembly ◽  
Colloidal Particles ◽  
Two Dimensional ◽  
Size Dependent

Emerging core-shell nanostructured catalysts of transition metal encapsulated by two-dimensional carbon materials for electrochemical applications

Nano Today ◽  
2018 ◽  
Vol 22 ◽  
pp. 100-131 ◽  
Author(s):  
Duy Thanh Tran ◽  
Tolendra Kshetri ◽  
Nguyen Dinh Chuong ◽  
Jagadis Gautam ◽  
Hoa Van Hien ◽  
...  
Keyword(s):  
Transition Metal ◽  
Carbon Materials ◽  
Nanostructured Catalysts ◽  
Core Shell ◽  
Two Dimensional ◽  
Electrochemical Applications

Surface Dependent Charge Carrier Dynamics in Core/Shell Nanoplatelets

2018 ◽  
Author(s):  
Sushma Yadav ◽  
Ajeet Singh Singh ◽  
Sameer Sapra Sapra ◽  
Nadja Bigall
Keyword(s):  
Charge Carrier ◽  
Carrier Dynamics ◽  
Core Shell ◽  
Charge Carrier Dynamics

Anchoring Core–Shell Cu@Cu2O Nanoparticles to Two-Dimensional Carbon Nanosheets for Bacterial Disinfection

2021 ◽  
Vol 4 (9) ◽  
pp. 9831-9841
Author(s):  
Guihong Sun ◽  
Shanshan Jia ◽  
Xiaoyan Zhang ◽  
Zewen Kang ◽  
Malin Cui ◽  
...  
Keyword(s):  
Core Shell ◽  
Two Dimensional ◽  
Carbon Nanosheets ◽  
Cu2o Nanoparticles ◽  
Bacterial Disinfection
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