Is There Real Upconversion Photoluminescence from Graphene Quantum Dots?

Gan, Zhixing; Wu, Xiaohong; Zhou, Gengxia; Shen, Jialin; Chu, Paul K.

doi:10.1002/adom.201300152

Cited by 134 publications

(87 citation statements)

References 34 publications

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“…Considering second-order diffraction light (λ/2) is always present in the selected excitation light (λ) due to limitation of diffraction gratings used in the monochromators of the spectrofluorimeter, the so-called UCL should be not real UCL but normal luminescence excited by the second-order diffraction light of wavelength λ/2. Gan and coworkers provided new evidences to support the conclusion of Tan [207]. The time resolved PL measurement of the CDs synthesized by hydrothermally treating GO was performed.…”

Section: Upconversion Luminescencementioning

confidence: 88%

“…23 a Emission spectra excited at 400 nm (black), 800 nm without (red) and with (blue) a 420 nm cutoff filter in the excitation channel [206]. b Time resolved PL monitored at 460 nm emission excited by the selected light of 320 (circles) and 640 nm (squares) [207] excitation source and the sample in order to eliminate the light at 400 nm (800/2) from light source), nearly no luminescence could be detected when excited at 800 nm. Considering second-order diffraction light (λ/2) is always present in the selected excitation light (λ) due to limitation of diffraction gratings used in the monochromators of the spectrofluorimeter, the so-called UCL should be not real UCL but normal luminescence excited by the second-order diffraction light of wavelength λ/2.…”

Section: Upconversion Luminescencementioning

confidence: 99%

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Carbon Based Dots and Their Luminescent Properties and Analytical Applications

Dong

Jian-Hua

Chi

2016

Carbon Nanoparticles and Nanostructures

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Carbon based dots (CDs) composed of sp 2 carbon structures and surface functional groups are a new kind of carbon nanomaterials, exhibiting unique luminescent properties due to the quantum confinement and edge effects. This chapter introduces CDs in detail from their synthetic strategies, morphological and structural characteristics, luminescent properties and mechanisms, and sensing applications. The synthesis methods are summarized as "top-down" and "bottomup" approaches. Luminescent properties discussed include photoluminescence, upconversion luminescence, chemiluminescence, electrochemiluminescence. Sensing applications mainly refer to the chemical and biological sensors based on the luminescent properties of CDs. This chapter provides an overview of the research field and gives future perspectives for developing the exciting materials.

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Section: Upconversion Luminescencementioning

confidence: 88%

Section: Upconversion Luminescencementioning

confidence: 99%

Carbon Based Dots and Their Luminescent Properties and Analytical Applications

Dong

Jian-Hua

Chi

2016

Carbon Nanoparticles and Nanostructures

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show abstract

“…Later, several other groups observed similar UCPL from CQDs prepared via different synthetic routes. For instance, Gan et al [39] demonstrated that blue light centered…”

Section: Up-conversion Photoluminescence (Ucpl)mentioning

confidence: 99%

Carbon Quantum Dots: A Component of Efficient Visible Light Photocatalysts

Cong,

Zhao

2018

Visible-Light Photocatalysis of Carbon-Based Materials

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Carbon quantum dots (CQDs) have been developed as a new member of nanocarbons, characterized by the relatively easy preparation from a wide spectrum of carbonaceous precursors through either bottom-up or top-down routes. Attractive optoelectronic properties have been observed with CQDs, including efficient light absorption, variable photoluminescence (PL), unique up-conversion PL and prominent electron transport ability, which make CQDs an important component with great potential in the design of efficient visible light-driven photocatalysts. In this chapter, detailed contribution of CQDs to the enhanced visible light-driven photocatalysis will be included, in the classification of the role as electron mediator, photosensitizer, spectral converter and sole photocatalyst.

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“…Nevertheless, some researchers argued that the up-conversion PL observed might be artificial, rather than from GQDs themselves. 22,23 It is demonstrated that the second-order diffraction light of Xenon lamp at l/2 coexisting in the excitation light actually may contribute to the observed up-conversion PL. In this point, the second order grating diffraction would be ruled out when considering the up-conversion phenomenon.…”

Section: Properties Of Gqdsmentioning

confidence: 98%

Properties and Synthesis Strategies of Graphene Quantum Dots

Zhang¹,

Lu²

2017

Frontiers in Nanobiomedical Research

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Quantum dots (QDs) are usually referred to as semiconductor nanoparticles with their sizes in the quantum-confined regime, in which the excitons are confined in all the three spatial dimensions. Typical QDs are inorganic semiconductor nanocrystals from the group II-VI elements in the periodic table. However, the applications of these QDs are limited by their internal disadvantages, including intrinsic toxicity (e.g. in the case of widely studied CdSe QDs) and problems caused by the colloidal stability. Therefore, developing new QDs and relevant nanomaterials is necessary. Consequently, graphene quantum dots (GQDs), a class of zero-dimensional (0D) graphitic nanomaterials, have attracted increasing attention recently. Compared with semiconductor QDs, GQDs are superior in terms of low cytotoxicity, high dispersity in water and some polarity organic solvents, resistance to photobleaching and biocompatibility. In addition, the properties of GQDs are easier to be tuned through surface chemistry, indicating that researchers can design GQDs with various functionalities for different applications.

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Is There Real Upconversion Photoluminescence from Graphene Quantum Dots?

Abstract: Figure 1. TEM images of GO (a) and GQDs (b). The inset of (b) shows the size distribution of GQDs with a probable size of 8.3 nm. wileyonlinelibrary.com

Cited by 134 publications

References 34 publications

Carbon Based Dots and Their Luminescent Properties and Analytical Applications

Carbon Based Dots and Their Luminescent Properties and Analytical Applications

Carbon Quantum Dots: A Component of Efficient Visible Light Photocatalysts

Properties and Synthesis Strategies of Graphene Quantum Dots

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