Physical Origin of Dual-Emission of Au–Ag Bimetallic Nanoclusters

On the origin of photoluminescence of noble metal NCs, there are always hot debates: metal-centered quantum-size confinement effect VS ligand-centered surface state mechanism. Herein, we provided solid evidence that structural water molecules (SWs) confined in the nanocavity formed by surface-protective-ligand packing on the metal NCs are the real luminescent emitters of Au-Ag bimetal NCs. The Ag cation mediated Au-Ag bimetal NCs exhibit the unique pH-dependent dual-emission characteristic with larger Stokes shift up to 200 nm, which could be used as potential ratiometric nanosensors for pH detection. Our results provide a completely new insight on the understanding of the origin of photoluminescence of metal NCs, which elucidates the abnormal PL emission phenomena, including solvent effect, pH-dependent behavior, surface ligand effect, multiple emitter centers, and large-Stoke’s shift.

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Epitaxial Growth: Out‐Of‐Plane Metal Coordination for a True Solvent‐Free Building with Molecular Bricks: Dodging the Surface Ligand Effect for On‐Surface Vacuum Self‐Assembly (Adv. Funct. Mater. 20/2021)

Advanced Functional Materials ◽

10.1002/adfm.202170142 ◽

2021 ◽

Vol 31 (20) ◽

pp. 2170142

Author(s):

Alessio Orbelli Biroli ◽

Alberto Calloni ◽

Alberto Bossi ◽

Madan S. Jagadeesh ◽

Guglielmo Albani ◽

...

Keyword(s):

Epitaxial Growth ◽

Self Assembly ◽

Solvent Free ◽

Metal Coordination ◽

Ligand Effect ◽

Out Of Plane ◽

Surface Ligand

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The Emission Property of Phosphors LEDs Based on ZnCuInS/ZnSe/ZnS Quantum Dots

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.989-994.623 ◽

2014 ◽

Vol 989-994 ◽

pp. 623-625

Author(s):

Ke Bi ◽

Wen Yan Liu ◽

Tian Yue Xu ◽

Tie Qiang Zhang ◽

Yu Zhang

Keyword(s):

Quantum Dots ◽

Photoluminescence Spectrum ◽

Stokes Shift ◽

Core Shell ◽

Photoluminescence Properties ◽

Red Emission ◽

Light Emitting ◽

Quantum Size ◽

Gan Led ◽

Photoluminescence Peak

.In this research, ZnCuInS/ZnSe/ZnS quantum dots (QDs) have been studied as an excellent red emitting source for blue GaN LED because of its non-toxic deep red emmission, and large Stokes shift properties. In the paper ZnCuInS/ZnSe/ZnS core/shell quantum dots were prepared with the particle size of 4.5nm. According to the measurement of photoluminescence spectrum emitted by ZnCuInS/ZnSe/ZnS core/shell quantum dots, the emitting peak of 700 nm and the full was achieved as red emitter.It was found that absorption edge and photoluminescence peak shifted to shorter wavelength with decreasing the nanocrystal size due to quantum size effect.Meanwhile, we were prepared ZnCuInS/ZnSe/ZnS core/shell quantum dot light emitting diodes and their photoluminescence properties were studied. After the suitable bias was applied on the films, increasing the ZnCuInS/ZnSe/ZnS QDs concentration in the blue GaN chips, red emission increased with decreasing LED’s blue light.

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