scholarly journals Quantum Yield Enhancement in Graphene Quantum Dots via Esterification with Benzyl Alcohol

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Suzuka Tachi ◽  
Hiroki Morita ◽  
Misaki Takahashi ◽  
Yusuke Okabayashi ◽  
Takuya Hosokai ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Benzyl Alcohol ◽  
Functional Groups ◽  
Photophysical Properties ◽  
Graphene Quantum Dots ◽  
Yield Enhancement ◽  
Light Illumination ◽  
Nonradiative Recombination ◽  
Widespread Application

Abstract The quantum yield of graphene quantum dots was enhanced by restriction of the rotation and vibration of surface functional groups on the edges of the graphene quantum dots via esterification with benzyl alcohol; this enhancement is crucial for the widespread application of graphene quantum dots in light-harvesting devices and optoelectronics. The obtained graphene quantum dots with highly graphene-stacked structures are understood to participate in π–π interactions with adjacent aromatic rings of the benzylic ester on the edges of the graphene quantum dots, thus impeding the nonradiative recombination process in graphene quantum dots. Furthermore, the crude graphene quantum dots were in a gel-like solid form and showed white luminescence under blue light illumination. Our results show the potential for improving the photophysical properties of nanomaterials, such as the quantum yield and band-gap energy for emission, by controlling the functional groups on the surface of graphene quantum dots through an organic modification approach.

Ball-Milling Graphite Used for Synthesis of Biocompatible Blue Luminescent Graphene Quantum Dots

2021 ◽  
Vol 6 (2) ◽  
Author(s):  
Zhou J ◽  
◽  
Dong Y ◽  
Ma Y ◽  
Zhang T ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ball Milling ◽  
Graphene Quantum Dots ◽  
Raw Material ◽  
Hydroxyl Groups ◽  
High Quality ◽  
Widespread Application ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron

Graphene Quantum Dots (GQDs) have been prepared by oxidationhydrothermal reaction, using ball-milling graphite as the starting materials. The prepared GQDs are endowed with excellent luminescence properties, with the optimum emission of 320nm. Blue photoluminescent emitted from the GQDs under ultraviolet light. The GQDs are ~3nm in width and 0.5~2 nm in thickness, revealed by high-resolution transmission electron microscopy and atomic force microscopy. In addition, Fourier transform infrared spectrum evidences the existence of carbonyl and hydroxyl groups, meaning GQDs can be dispersed in water easily and used in cellar imaging, and blue area inside L929 cells were clearly observed under the fluorescence microscope. Both low price of raw material and simple prepared method contribute to the high quality GQDs widespread application in future.

Ultra-bright alkylated graphene quantum dots

Nanoscale ◽  
2014 ◽  
Vol 6 (21) ◽  
pp. 12635-12643 ◽  
Author(s):  
Lan Feng ◽  
Xing-Yan Tang ◽  
Yun-Xin Zhong ◽  
Yue-Wen Liu ◽  
Xue-Huan Song ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Graphene Quantum Dots

Alkylated graphene quantum dots with negligible oxygen-containing groups exhibit pH-independent and ultra-bright PL with a quantum yield of up to 65%.

A reformative oxidation strategy using high concentration nitric acid for enhancing the emission performance of graphene quantum dots

RSC Advances ◽  
2014 ◽  
Vol 4 (89) ◽  
pp. 47977-47981 ◽  
Author(s):  
Taili Shao ◽  
Guodong Wang ◽  
Xuting An ◽  
Shujuan Zhuo ◽  
Yunsheng Xia ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Nitric Acid ◽  
Quantum Yield ◽  
Graphene Quantum Dots ◽  
High Concentration ◽  
Emission Performance

Red fluorescent graphene quantum dots with 18% quantum yield at 600 nm were obtained through a concentrated HNO3oxidation strategy.

scholarly journals Cellular distribution and cytotoxicity of graphene quantum dots with different functional groups

2014 ◽  
Vol 9 (1) ◽  
pp. 108 ◽  
Author(s):  
Xiaochan Yuan ◽  
Zhiming Liu ◽  
Zhouyi Guo ◽  
Yanhong Ji ◽  
Mei Jin ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Cellular Distribution

Photophysical properties and photodynamic therapy activity of ameso-tetra(4-carboxyphenyl)porphyrin tetramethyl ester–graphene quantum dot conjugate

2019 ◽  
Vol 43 (11) ◽  
pp. 4518-4524 ◽  
Author(s):  
Muthumuni Managa ◽  
Bokolombe Pitchou Ngoy ◽  
Tebello Nyokong
Keyword(s):  
Quantum Dots ◽  
Photodynamic Therapy ◽  
Quantum Dot ◽  
Photophysical Properties ◽  
Graphene Quantum Dots ◽  
Graphene Quantum Dot

Ameso-tetra(4-carboxyphenyl)porphyrin tetramethyl ester and the Zn and GaCl derivatives were π–π stacked with graphene quantum dots to form conjugates and their photophysical and photodynamic therapy properties were investigated.

Tunable Ionic Conductivity and Photoluminescence in Quasi-2D CH3NH3PbBr3 Thin Film Incorporating Sulphur Doped Graphene Quantum Dots

2021 ◽  
Author(s):  
Ramesh Kumar ◽  
Jitendra Kumar ◽  
Sachin Kadian ◽  
Priya Srivastava ◽  
Gaurav Manik ◽  
...  
Keyword(s):  
Thin Film ◽  
Quantum Dots ◽  
Ionic Conductivity ◽  
Operating Temperature ◽  
Graphene Quantum Dots ◽  
Light Illumination ◽  
Applied Bias ◽  
Ion Migration ◽  
Doped Graphene ◽  
Halide Perovskites

Ion migration in hybrid halide perovskites is ubiquitous in all conditions. However, ionic conductivity can be manipulated by changing the material composition, operating temperature, light illumination, applied bias as well...

Sustainable synthesis of single crystalline sulphur-doped graphene quantum dots for bioimaging and beyond

2018 ◽  
Vol 20 (18) ◽  
pp. 4245-4259 ◽  
Author(s):  
Sujata Sangam ◽  
Apoorv Gupta ◽  
Adeeba Shakeel ◽  
Rohan Bhattacharya ◽  
Arun Kumar Sharma ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
Graphene Quantum Dots ◽  
Hydrothermal Route ◽  
Single Crystalline ◽  
Doped Graphene

Waste-driven single crystalline sulphur-doped GQDs are synthesized via a green hydrothermal route with the highest quantum yield and excellent biocompatibility for bioimaging.

How functional groups influence the ROS generation and cytotoxicity of graphene quantum dots

2017 ◽  
Vol 53 (76) ◽  
pp. 10588-10591 ◽  
Author(s):  
Ya Zhou ◽  
Hanjun Sun ◽  
Faming Wang ◽  
Jinsong Ren ◽  
Xiaogang Qu
Keyword(s):  
Quantum Dots ◽  
Functional Groups ◽  
Graphene Quantum Dots ◽  
Ros Generation ◽  
Hydroxyl Groups ◽  
Carbonyl Groups ◽  
Oxygen Functional Groups

Herein we selectively deactivate the ketonic carbonyl, carboxylic, or hydroxyl groups on GQDs and compare their ROS generation ability. The ROS generation ability of GQDs is closely related to these oxygen functional groups, especially for the ketonic carbonyl groups.

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