Photon-Induced Light Emission from Foamed Gold with Micro/Nanohollow Sphere Structures

We present a detailed investigation on the effect of functional group modulation at the edges of carbon quantum dots (CQDs) on the fluorescence from the CQDs. The CQDs attached by N, S, and P elements are synthesized via pyrolysis of a mixture of citric acid and NH 3 H 2 O, H 2 SO 4 , and H 3 PO 4 , respectively. Thus, part of –COOH at the edges of CQDs can be converted into –C=O and functional groups such as –NH 2 , –SO 2 , –HSO 3 , and –H 2 PO 4 can connect to the carbon bonds. We find that the formation of the N/S/P-CQDs can reduce the amount of –COOH that attaches to the edges of sp 2 -conjugated π -domains located at centers of these CQDs. This effect can result in the reduction of the non-radiative recombination for electronic transition in these CQDs. As a result, the quantum yield (QY) for fluorescence from the CQDs can be efficiently enhanced. We demonstrate experimentally that the QYs for N/S/P-CQDs can reach up to 18.7%, 29.7%, and 10.3%, respectively, in comparison to 9% for these without functional group modulation. This work can provide a practical experimental approach in improving the optical properties of fluorescent CQDs.

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“…This effect has been found in most nano-structured materials (see, e.g., Ref. [45]). As has been pointed out by Ref.…”

Section: Resultssupporting

confidence: 53%

Influence of Group Modification at the Edges of Carbon Quantum Dots on Fluorescent Emission

Tang

Zhang

et al. 2019

Nanoscale Res Lett

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“…weakly on λex, where λem=419 nm for T28, 422 nm for A28, 430 nm for C28, and 406 nm for G28 respectively. These results imply that in this λex regime, i) the PL emission from a ssDNA sample is mainly induced by exciton-like electronic transitions via combination and separation of the electron-hole pairs 21 ; ii) the energy difference between the LUMO and HOMO states for excitonic transitions differs for ssDNA with different bases; and iii) the maximum excitation wavelength λexm for this regime also differs for different ssDNA samples, where λexm=330 nm for T28 and A28 and 300 nm for C28 and G28 respectively. Secondly, at long wavelength excitations (λex> λexm), λem from ssDNA depends strongly on λex and different samples show different dependences.…”

Section: Resultsmentioning

confidence: 78%

Photoluminescence and electronic transition behaviors of single-stranded DNA

Wang

Lin

et al. 2021

Phys. Rev. E

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We present a systematic investigation of the photoluminescence (PL) from singlestrand DNA (ssDNA) with different bases (T, A, C and G) and different base numbers (20, 35 and 56). We find that the features of the PL emission from these samples depend sensitively and characteristically on the base structure and base number of the ssDNA.The results obtained from the PL and PL excitation (PLE) measurements indicate that the dependence of the PL and PLE peak wavelengths upon the excitation wavelength can exhibit different features for ssDNA with different base structures and base numbers.Through examining the dependence of the PL and PLE peaks along with the amplitude of the PL peaks upon the excitation wavelength, we are able to identify optically the ssDNA with different bases and the same base but with different base numbers. Thus, one can achieve a non-invasive and label free characterization of the ssDNA by the standard PL measurement. We also propose and examine the possible mechanisms for PL from ssDNA in different excitation wavelength regimes. It is found that the PL from ssDNA is akin to that from a direct band-gap semiconductor with radiative impurity states. This work is relevant to the application of the state-of-the-art optical technique for the characterization and investigation of the DNA structures.

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“…The quantum yield of gold in the bulk state is almost negligible (order 10 À10 ) which can be increased by an order of magnitude by reducing the size of the gold at the nanoscale [13,14]. This enhancement in quantum yield by order at the nanoscale produces an increase in the optical storage capacity by many folds and it is also capable of producing unbleachable stains in the bio-imaging process because the PL of the gold nanoparticles is very unlikely to undergo a photo-bleaching effect [15].…”

Section: Introductionmentioning

confidence: 99%

X‐ray photoelectron spectroscopy and tunable photoluminescence study of gold nanoparticles embedded in PVA films

Gautam,

Singh,

Gautam

et al. 2023

Luminescence

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This paper reports the systematic photoluminescence study of the various contents of the gold nanocomposites in the PVA films. The variations in the gold content in PVA film were 0.2, 0.5, 1.0, and 1.5 wt.%. All the samples were excited at two selected wavelengths; those are at 400 nm and 532 nm. On exciting the Au‐PVA nanocomposites films at 400 nm the photoluminescence was observed in the region of 430‐500 nm in comparison to pure PVA films that show the emission at 400 nm. However, on the exciting the Au‐PVA nanocomposites at 532 nm, the emission was observed at560‐650 nm with a long tail till 700 nm that is unlike the pure PVA films that do not show any emission peak in this region. This suggests that emission between 430‐500 nm regions is due to the coordination of PVA with gold nanoparticles because the PVA has the emission at 400 nm. However, the emission peak between 560‐650 nm is entirely due to the gold nm particle. The peak also shows the smaller red‐shift that is usually with the increasing nanoparticles size with the increasing content in the PVA films. The formation of gold nanoparticles was justified by the XRD analysis which is further supported by the XPS analysis.

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Photon-Induced Light Emission from Foamed Gold with Micro/Nanohollow Sphere Structures

Cited by 4 publications

References 17 publications

Influence of Group Modification at the Edges of Carbon Quantum Dots on Fluorescent Emission

Influence of Group Modification at the Edges of Carbon Quantum Dots on Fluorescent Emission

Photoluminescence and electronic transition behaviors of single-stranded DNA

X‐ray photoelectron spectroscopy and tunable photoluminescence study of gold nanoparticles embedded in PVA films

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