Luminescence Change of CdS and CdSe Quantum Dots on a Ag Film

Abstract

Enhanced luminescence of an emitter on a Ag film is usually ascribed to the resonant surface plasmons. In these studies, the solid cadmium sulfide (CdS) and cadmium selenide (CdSe) quantum dot/silver (QD/Ag) hybrids were prepared, and the luminescence characteristics of these QD/Ag hybrids were measured. It is found that the enhancement of the trap state emission (TSE) is related to the QD size. The TSE features of the annealed QD/Ag hybrids are insensitive to the morphology of the Ag film. We used the wet and dry methods to separate the QD and Ag components and found that the photoluminescence (PL) of the QD component was permanently changed from the initial state. The PL modification is ascribed to the Ag + doping effect rather than the surface plasmons. This doping method uses pure Ag as the Ag + ion source. In this case, though the CdS and CdSe QD/Ag hybrids are the solid state, the cation exchange between Ag + and Cd 2+ ions can still occur on the QD surface. Even a small amount of Ag can efficiently influence the luminescence of the QDs embedded in the poly(methyl methacrylate) matrix. A hypothetical model was proposed to explain the PL modification of the QD/Ag hybrid with and without annealing. Using this dry method for doping, the transparent luminescence label can be prepared easily, and the doped QDs can be further doped with Ag + dopants.

Electric Field Tunability of Photoluminescence from a Hybrid Peptide–Plasmonic Metal Microfabricated Chip

“…Bottom-up fabrication methods based on self-assembly, however, have proved to be a reproducible, highly sensitive method for PEF substrate fabrication. 10 , 14 , 21 , 25 …”

“…These techniques generally have a limitation, either high cost or lack of reproducibility or sensitivity. Bottom-up fabrication methods based on self-assembly, however, have proved to be a reproducible, highly sensitive method for PEF substrate fabrication. ,,, …”

“…Bottom-up fabrication methods based on self-assembly, however, have proved to be a reproducible, highly sensitive method for PEF substrate fabrication. 10,14,21,25 Peptide-based nanofabrication is an appealing method for making nanomaterials, given the use of peptides for molecular recognition and their elevated thermal and chemical stability, 26,27 as well as their easy chemical preparation that does not require heavy metals, strong acids, or harsh chemical substances. 26,27 Among the numerous peptide-molecule-based nanostructures, diphenylalanine (Phe-Phe, FF) is a frequently used building-block peptide that can form various structures such as nanotubes through self-assembly processes.…”

The optical properties of PbS and PbS/Ag thin films

“…Many fabrication method have been used to deposit PbS thin films, including solid vapor deposition [10], chemical bath deposition (CBD) [11], spray coated [12] , spin-coating [13], and electrodeposition [14] silver (Ag) was used as a coating for many semiconductors like CdS thin films [15], CdSe [16], and PbS [17] to reduce the health risk and toxicity of this material, which have no undesirable effects on humans Based on our prior research into CdS/Ag hybrid thin film optical qualities, we've worked to uncover the mechanism between the Ag layer and the PbS hybrid in the current manuscript, which we're submitting for publication here. Comparing optical properties of CdS film before and after Ag layer deposition were studied, emphasizing the significant reduction in energy gap as well as an increase in absorption.…”

Synthesis of CdS/CdSe Core/Shell Heterostructures Using Ultrasonic Assisted Sol–Gel Method

“…II-VI chalcogenide nano semiconductors are promising materials for scientific and technological applications such as solar cells [1], light emitting diodes [2] and photocatalysts [3] due to their fundamental excitonic properties [4][5][6][7]. Out of them CdS, CdSe and CdTe have shown high extinction coefficient, photo-stability, tunable band gap and good light absorbing capacity make them suitable for effective charge separation in optoelectronic devices [8][9][10][11]. The small size of these particles leads to a large surface area to volume ratio, which results in large increase in chemical reactivity of the surface.…”