Discover the SciOpen Platform and Achieve Your Research Goals with Ease.
Search articles, authors, keywords, DOl and etc.
At present, the actual mechanism of the photoluminescence (PL) of fluorescent carbon dots (CDs) is still an open debate among researchers. Because of the variety of CDs, it is highly important to summarize the PL mechanism for these kinds of carbon materials; doing so can guide the development of effective synthesis routes and novel applications. This review will focus on the PL mechanism of CDs. Three types of fluorescent CDs were involved: graphene quantum dots (GQDs), carbon nanodots (CNDs), and polymer dots (PDs). Four reasonable PL mechanisms have been confirmed: the quantum confinement effect or conjugated π-domains, which are determined by the carbon core; the surface state, which is determined by hybridization of the carbon backbone and the connected chemical groups; the molecule state, which is determined solely by the fluorescent molecules connected on the surface or interior of the CDs; and the crosslink-enhanced emission (CEE) effect. To give a thorough summary, the category and synthesis routes, as well as the chemical/physical properties for the CDs, are briefly introduced in advance.
Baker, S. N.; Baker, G. A. Luminescent carbon nanodots: Emergent nanolights. Angew. Chem. Int. Ed. 2010, 49, 6726-6744.
Li, H. T.; Kang, Z. H.; Liu, Y.; Lee, S. -T. Carbon nanodots: Synthesis, properties and applications. J. Mater. Chem. 2012, 22, 24230-24253.
Welsher, K.; Liu, Z.; Sherlock, S. P.; Robinson, J. T.; Chen, Z.; Daranciang, D.; Dai, H. J. A route to brightly fluorescent carbon nanotubes for near-infrared imaging in mice. Nat. Nanotechol. 2009, 4, 773-780.
Gokus, T.; Nair, R. R.; Bonetti, A.; Bohmler, M.; Lombardo, A.; Novoselov, K. S.; Geim, A. K.; Ferrari, A. C.; Hartschuh, A. Making graphene luminescent by oxygen plasma treatment. ACS Nano 2009, 3, 3963-3968.
Eda, G.; Lin, Y. -Y.; Mattevi, C.; Yamaguchi, H.; Chen, H. -A.; Chen, I. -S.; Chen, C. -W.; Chhowalla, M. Blue photoluminescence from chemically derived graphene oxide. Adv. Mater. 2010, 22, 505-509.
Zhu, S. J.; Tang, S. J.; Zhang, J. H.; Yang, B. Control the size and surface chemistry of graphene for the rising fluorescent materials. Chem. Commun. 2012, 48, 4527-4539.
Shen, J. H.; Zhu, Y. H.; Yang, X. L.; Li, C. Z. Graphene quantum dots: emergent nanolights for bioimaging, sensors, catalysis and photovoltaic devices. Chem. Commun. 2012, 48, 3686-3699.
Zhang, Z. P.; Zhang, J.; Chen, N.; Qu, L. T. Graphene quantum dots: An emerging material for energy-related applications and beyond. Energy Environ. Sci. 2012, 5, 8869-8890.
Li, L. L.; Wu, G. H.; Yang, G. H.; Peng, J.; Zhao, J. W.; Zhu, J. -J. Focusing on luminescent graphene quantum dots: Current status and future perspectives. Nanoscale 2013, 5, 4015-4039.
Bacon, M.; Bradley, S. J.; Nann, T. Graphene quantum dots. Part. Part. Syst. Charact. 2014, 31, 415-428.
Zhou, X. J.; Guo, S. W.; Zhang, J. Y. Solution-processable graphene quantum dots. ChemPhysChem 2013, 14, 2627-2640.
Lin, L. P.; Rong, M. C.; Luo, F.; Chen, D. M.; Wang, Y. R.; Chen, X. Luminescent graphene quantum dots as new fluorescent materials for environmental and biological applications. TrAC Trends Anal. Chem. 2014, 54, 83-102.
Liu, S.; Tian, J. Q.; Wang, L.; Zhang, Y. W.; Qin, X. Y.; Luo, Y. L.; Asiri, A. M.; Al-Youbi, A. O.; Sun, X. P. Hydrothermal treatment of grass: A low-cost, green route to nitrogen-doped, carbon-rich, photoluminescent polymer nanodots as an effective fluorescent sensing platform for label-free detection of Cu(II) ions. Adv. Mater. 2012, 24, 2037-2041.
Qiao, Z. -A.; Huo, Q. S.; Chi, M. F.; Veith, G. M.; Binder, A. J.; Dai, S. A "ship-in-a-bottle" approach to synthesis of polymer dots@silica or polymer dots@carbon core-shell nanospheres. Adv. Mater. 2012, 24, 6017-6021.
Zhu, S. J.; Zhang, J. H; Wang, L.; Song, Y. B.; Zhang, G. Y.; Wang, H. Y.; Yang, B. A general route to make non-conjugated linear polymers luminescent. Chem. Commun. 2012, 48, 10889-10891.
Yu, S. -J.; Kang, M. -W.; Chang, H. -C.; Chen, K. -M.; Yu, Y. -C. Bright fluorescent nanodiamonds: No photobleaching and low cytotoxicity. J. Am. Chem. Soc. 2005, 127, 17604-17605.
Mochalin, V. N.; Shenderova, O.; Ho, D.; Gogotsi, Y. The properties and applications of nanodiamonds. Nat. Nanotechnol. 2012, 7, 11-23.
Cao, L.; Meziani, M. J.; Sahu, S.; Sun, Y. -P. Photoluminescence properties of graphene versus other carbon nanomaterials. Acc. Chem. Res. 2013, 46, 171-180.
Song, Y. B.; Zhu, S. J.; Yang, B. Bioimaging based on fluorescent carbon dots. RSC Adv. 2014, 4, 27184-27200.
Feng, X. L.; Wu, J. S.; Ai, M.; Pisula, W.; Zhi, L. J.; Rabe, J. P.; Müllen, K. Triangle-shaped polycyclic aromatic hydrocarbons. Angew. Chem. Int. Ed. 2007, 46, 3033-3036.
Yan, X.; Cui, X.; Li, L. -S. Synthesis of large, stable colloidal graphene quantum dots with tunable size. J. Am. Chem. Soc. 2010, 132, 5944-5945.
Qiao, Z. -A.; Wang, Y. F.; Gao, Y.; Li, H. W.; Dai, T. Y.; Liu, Y. L.; Huo, Q. S. Commercially activated carbon as the source for producing multicolor photoluminescent carbon dots by chemical oxidation. Chem. Commun. 2010, 46, 8812-8814.
Li, H. T.; He, X. D.; Kang, Z. H.; Huang, H.; Liu, Y.; Liu, J. L.; Lian, S. Y.; Tsang, C. H.; Yang, X. B.; Lee, S. -T. Water-soluble fluorescent carbon quantum dots and photocatalyst design. Angew. Chem. Int. Ed. 2010, 49, 4430-4434.
Peng, J.; Gao, W.; Gupta, B. K.; Liu, Z.; Romero-Aburto, R.; Ge, L. H.; Song, L. H.; Alemany, L. B.; Zhan, X. B.; Gao, G. H. et al. Graphene quantum dots derived from carbon fibers. Nano Lett. 2012, 12, 844-849.
Xu, X.Y.; Ray, R.; Gu, Y. L.; Ploehn, H. J.; Gearheart, L.; Raker, K.; Scrivens, W. A. Electrophoretic analysis and purification of fluorescent single-walled carbon nanotube fragments. J. Am. Chem. Soc. 2004, 126, 12736-12737.
Shinde, D. B.; Pillai, V. K. Electrochemical preparation of luminescent graphene quantum dots from multiwalled carbon nanotubes. Chem. -Eur. J. 2012, 18, 12522-12528.
Dong, Y. Q.; Chen, C. Q.; Zheng, X. T.; Gao, L. L.; Cui, Z. M.; Yang, H. B.; Guo, C. X.; Chi, Y. W.; Li, C. M. One-step and high yield simultaneous preparation of single-and multi-layer graphene quantum dots from CX-72 carbon black. J. Mater. Chem. 2012, 22, 8764-8766.
Liu, H. P.; Ye, T.; Mao, C. D. Fluorescent carbon nanoparticles derived from candle soot. Angew. Chem. Int. Ed. 2007, 46, 6473-6475.
Tao, H. Q.; Yang, K.; Ma, Z.; Wan, J. M.; Zhang, Y. J.; Kang, Z. H.; Liu, Z. In vivo NIR fluorescence imaging, biodistribution, and toxicology of photoluminescent carbon dots produced from carbon nanotubes and graphite. Small 2012, 8, 281-290.
Zhu, S. J.; Zhang, J. H.; Qiao, C. Y.; Tang, S. J.; Li, Y. F.; Yuan, W. J.; Li, B.; Tian, L.; Liu, F.; Hu, R. et al. Strongly green-photoluminescent graphene quantum dots for bioimaging applications. Chem. Commun. 2011, 47, 6858-6860.
Zhu, S. J.; Zhang, J. H.; Liu, X.; Li, B.; Wang, X. F.; Tang, S. J.; Meng, Q. N.; Li, Y. F.; Shi, C.; Hu, R. et al. Graphene quantum dots with controllable surface oxidation, tunable fluorescence and up-conversion emission. RSC Adv. 2012, 2, 2717-2720.
Lu, J.; Yang, J. -X.; Wang, J. Z.; Lim, A.; Wang, S.; Loh, K. P. One-pot synthesis of fluorescent carbon nanoribbons, nanoparticles, and graphene by the exfoliation of graphite in ionic liquids. ACS Nano 2009, 3, 2367-2375.
Zheng, L. Y.; Chi, Y. W.; Dong, Y. Q.; Lin, J. P.; Wang, B. B. Electrochemiluminescence of water-soluble carbon nanocrystals released electrochemically from graphite. J. Am. Chem. Soc. 2009, 131, 4564-4565.
Pan, D. Y.; Zhang, J. C.; Li, Z.; Wu, M. H. Hydrothermal route for cutting graphene sheets into blue-luminescent graphene quantum dots. Adv. Mater. 2010, 22, 734-738.
Lin, L. X.; Zhang, S. W. Creating high yield water soluble luminescent graphene quantum dots via exfoliating and disintegrating carbon nanotubes and graphite flakes. Chem. Commun. 2012, 48, 10177-10179.
Bottini, M.; Balasubramanian, C.; Dawson, M. I.; Bergamaschi, A.; Bellucci, S.; Mustelin, T. Isolation and characterization of fluorescent nanoparticles from pristine and oxidized electric arc-produced single-walled carbon nanotubes. J. Phys. Chem. B 2006, 110, 831-836.
Sun, Y. -P.; Zhou, B.; Lin, Y.; Wang, W.; Fernando, K. A.; Pathak, P.; Meziani, M. J.; Harruff, B. A.; Wang, X.; Wang, H. F. et al. Quantum-sized carbon dots for bright and colorful photoluminescence. J. Am. Chem. Soc. 2006, 128, 7756-7757.
Lee, J.; Kim, K.; Park, W. I.; Kim, B. -H.; Park, J. H.; Kim, T. -H.; Bong, S.; Kim, C. -H.; Chae, G.; Jun, M. et al. Uniform graphene quantum dots patterned from self-assembled silica nanodots. Nano Lett. 2012, 12, 6078-6083.
Fan, L. L.; Zhu, M.; Lee, X.; Zhang, R. J.; Wang, K. L.; Wei, J. Q.; Zhong, M. L.; Wu, D. H.; Zhu, H. W. Direct synthesis of graphene quantum dots by chemical vapor deposition. Part. Part. Syst. Charact. 2013, 30, 764-769.
Zhao, Q. -L.; Zhang, Z. -L.; Huang, B. -H.; Peng, J.; Zhang, M.; Pang, D. -W. Facile preparation of low cytotoxicity fluorescent carbon nanocrystals by electrooxidation of graphite. Chem. Commun. 2008, 5116-5118.
Bao, L.; Zhang, Z. -L.; Tian, Z. -Q.; Zhang, L.; Liu, C.; Lin, Y.; Qi, B. P.; Pang, D. -W. Electrochemical tuning of luminescent carbon nanodots: From preparation to luminescence mechanism. Adv. Mater. 2011, 23, 5801-5806.
Li, Y.; Hu, Y.; Zhao, Y.; Shi, G. Q.; Deng, L. E.; Hou, Y. B.; Qu, L. T. An electrochemical avenue to green-luminescent graphene quantum dots as potential electron-acceptors for photovoltaics. Adv. Mater. 2011, 23, 776-780.
Deng, J. H.; Lu, Q. J.; Mi, N. X.; Li, H. T.; Liu, M. L.; Xu, M. C.; Tan, L.; Xie, Q. J.; Zhang, Y. Y.; Yao, S. Z. Electrochemical synthesis of carbon nanodots directly from alcohols. Chem. -Eur. J. 2014, 20, 4993-4999.
Zhou, X. J.; Zhang, Y.; Wang, C.; Wu, X. C.; Yang, Y. Q.; Zheng, B.; Wu, H. X.; Guo, S. W.; Zhang, J. Y. Photo-Fenton reaction of graphene oxide: a new strategy to prepare graphene quantum dots for DNA cleavage. ACS Nano 2012, 6, 6592-6599.
Yang, Z. -C.; Wang, M.; Yong, A. M.; Wong, S. Y.; Zhang, X. -H.; Tan, H.; Chang, A. Y.; Li, X.; Wang, J. Intrinsically fluorescent carbon dots with tunable emission derived from hydrothermal treatment of glucose in the presence of monopotassium phosphate. Chem. Commun. 2011, 47, 11615-11617.
Zhu, H.; Wang, X. L.; Li, Y. L.; Wang, Z. J.; Yang, F.; Yang, X. R. Microwave synthesis of fluorescent carbon nanoparticles with electrochemiluminescence properties. Chem. Commun. 2009, 5118-5120.
Bourlinos, A. B.; Stassinopoulos, A.; Anglos, D.; Zboril, R.; Karakassides, M.; Giannelis, E. P. Surface functionalized carbogenic quantum dots. Small 2008, 4, 455-458.
Peng, H.; Travas-Sejdic, J. Simple aqueous solution route to luminescent carbogenic dots from carbohydrates. Chem. Mater. 2009, 21, 5563-5565.
Zong, J.; Zhu, Y. H.; Yang, X. L.; Shen, J. H.; Li, C. Z. Synthesis of photoluminescent carbogenic dots using mesoporous silica spheres as nanoreactors. Chem. Commun. 2011, 47, 764-766.
Tang, L. B.; Ji, R. B.; Cao, X. K.; Lin, J. Y.; Jiang, H. X.; Li, X. M.; Teng, K. S.; Luk, C. M.; Zeng, S. J.; Hao, J. H. et al. Deep ultraviolet photoluminescence of water-soluble self-passivated graphene quantum dots. ACS Nano 2012, 6, 5102-5110.
Wang, J.; Wang, C. -F.; Chen, S. Amphiphilic egg-derived carbon dots: Rapid plasma fabrication, pyrolysis process, and multicolor printing patterns. Angew. Chem. Int. Ed. 2012, 51, 9297-9301.
Zhang, C.; Liu, Y.; Xiong, X. -Q.; Peng, L. -H.; Gan, L.; Chen, C. -F.; Xu, H. -B. Three-dimensional nanographene based on triptycene: Synthesis and its application in fluorescence imaging. Org. Lett. 2012, 14, 5912-5915.
Cao, L.; Wang, X.; Meziani, M. J.; Lu, F. S.; Wang, H. F.; Luo, P. J. G.; Lin, Y.; Harruff, B. A.; Veca, L. M.; Murray, D.; Xie, S. -Y.; Sun, Y. -P. Carbon dots for multiphoton bioimaging. J. Am. Chem. Soc. 2007, 129, 11318-11319.
Shen, J. H.; Zhu, Y. H.; Chen, C.; Yang, X. L.; Li, C. Z. Facile preparation and upconversion luminescence of graphene quantum dots. Chem. Commun. 2011, 47, 2580-2582.
Zhu, S. J.; Wang, L.; Zhou, N.; Zhao, X. H.; Song, Y. B.; Maharjan, S.; Zhang, J. H.; Lu, L. J.; Wang, H. Y.; Yang, B. The crosslink enhanced emission (CEE) in non-conjugated polymer dots: From the photoluminescence mechanism to the cellular uptake mechanism and internalization. Chem. Commun. 2014, 50, 13845-13848.
Zheng, H. Z.; Wang, Q. L.; Long, Y. J.; Zhang, H. J.; Huang, X. X.; Zhu, R. Enhancing the luminescence of carbon dots with a reduction pathway. Chem. Commun. 2011, 47, 10650-10652.
Nie, H.; Li, M. J.; Li, Q. S.; Liang, S. J.; Tan, Y. Y.; Sheng, L.; Shi, W.; Zhang, S. X. -A. Carbon dots with continuously tunable full-color emission and their application in ratiometric pH sensing. Chem. Mater. 2014, 26, 3104-3112.
Tetsuka, H.; Asahi, R.; Nagoya, A.; Okamoto, K.; Tajima, I.; Ohta, R.; Okamoto, A. Optically tunable amino-functionalized graphene quantum dots. Adv. Mater. 2012, 24, 5333-5338.
Wang, Y.; Kalytchuk, S.; Zhang, Y.; Shi, H. C.; Kershaw, S. V.; Rogach, A. L. Thickness-dependent full-color emission tunability in a flexible carbon dot ionogel. J. Phys. Chem. Lett. 2014, 5, 1412-1420.
Wang, Y. Y.; Li, Y.; Yan, Y.; Xu, J.; Guan, B. Y.; Wang, Q.; Li, J. Y.; Yu, J. H. Luminescent carbon dots in a new magnesium aluminophosphate zeolite. Chem. Commun. 2013, 49, 9006-9008.
Ray, S. C.; Saha, A.; Jana, N. R.; Sarkar, R. Fluorescent carbon nanoparticles: Synthesis, characterization, and bioimaging application. J. Phys. Chem. C 2009, 113, 18546-18551.
Wang, X. H.; Qu, K. G.; Xu, B. L.; Ren, J. S.; Qu, X. G. Multicolor luminescent carbon nanoparticles: Synthesis, supramolecular assembly with porphyrin, intrinsic peroxidase-like catalytic activity and applications. Nano Res. 2011, 4, 908-920.
Bhunia, S. K.; Saha, A.; Maity, A. R.; Ray, S. C.; Jana, N. R. Carbon nanoparticle-based fluorescent bioimaging probes. Sci. Rep. 2013, 3, 1473.
Qu, D.; Zheng, M.; Zhang, L. G.; Zhao, H. F.; Xie, Z. G.; Jing, X. B.; Haddad, R. E.; Fan, H. Y.; Sun, Z. C. Formation mechanism and optimization of highly luminescent N-doped graphene quantum dots. Sci. Rep. 2014, 4, 5294.
Zhu, S. J.; Meng, Q. N.; Wang, L.; Zhang, J. H.; Song, Y. B.; Jin, H.; Zhang, K.; Sun, H.; Wang, H. C.; Yang, B. Highly photoluminescent carbon dots for multicolor patterning, sensors, and bioimaging. Angew. Chem. Int. Ed. 2013, 52, 3953-3957.
Gan, Z. X.; Wu, X. L.; Zhou, G. X.; Shen, J. C.; Chu, P. K. Is there real upconversion photoluminescence from graphene quantum dots? Adv. Opt. Mater. 2013, 1, 554-558.
Wen, X. M.; Yu, P.; Toh, Y. R.; Ma, X. Q.; Tang, J. On the upconversion fluorescence in carbon nanodots and graphene quantum dots. Chem. Commun. 2014, 50, 4703-4706.
Qu, S. N.; Liu, X. Y.; Guo, X. Y.; Chu, M. H.; Zhang, L. G.; Shen, D. Z. Amplified spontaneous green emission and lasing emission from carbon nanoparticles. Adv. Funct. Mater. 2014, 24, 2689-2695.
Fan, L. S.; Hu, Y. W.; Wang, X.; Zhang, L. L.; Li, F. H.; Han, D. X.; Li, Z. G.; Zhang, Q. X.; Wang, Z. X.; Niu, L. Fluorescence resonance energy transfer quenching at the surface of graphene quantum dots for ultrasensitive detection of TNT. Talanta 2012, 101, 192-197.
Luo, P. J. G.; Sahu, S.; Yang, S. -T.; Sonkar, S. K.; Wang, J. P.; Wang, H. F.; LeCroy, G. E.; Cao, L.; Sun, Y. -P. Carbon "quantum" dots for optical bioimaging. J. Mater. Chem. B 2013, 1, 2116-2127.
Esteves da Silva, J. C. G.; Gonçalves, H. M. R. Analytical and bioanalytical applications of carbon dots. TrAC Trends Anal. Chem. 2011, 30, 1327-1336.
Sun, X. M.; Liu, Z.; Welsher, K.; Robinson, J. T.; Goodwin, A.; Zaric, S.; Dai, H. J. Nano-graphene oxide for cellular imaging and drug delivery. Nano Res. 2008, 1, 203-212.
Goh, E. J.; Kim, K. S.; Kim, Y. R.; Jung, H. S.; Beack, S.; Kong, W. H.; Scarcelli, G.; Yun, S. H.; Hahn, S. K. Bioimaging of hyaluronic acid derivatives using nanosized carbon dots. Biomacromolecules 2012, 13, 2554-2561.
Kong, B.; Zhu, A. W.; Ding, C. Q.; Zhao, X. M.; Li, B.; Tian, Y. Carbon dot-based inorganic-organic nanosystem for two-photon imaging and biosensing of pH variation in living cells and tissues. Adv. Mater. 2012, 24, 5844-5848.
Liu, C. J.; Zhang, P.; Zhai, X. Y.; Tian, F.; Li, W. C.; Yang, J. H.; Liu, Y.; Wang, H. B.; Wang, W.; Liu, W. G. Nano-carrier for gene delivery and bioimaging based on carbon dots with PEI-passivation enhanced fluorescence. Biomaterials 2012, 33, 3604-3613.
Nurunnabi, M.; Khatun, Z.; Huh, K. M.; Park, S. Y.; Lee, D. Y.; Cho, K. J.; Lee, Y. K. In vivo biodistribution and toxicology of carboxylated graphene quantum dots. ACS Nano 2013, 7, 6858-6867.
Qian, J.; Wang, D.; Cai, F. -H.; Xi, W.; Peng, L.; Zhu, Z. -F.; He, H.; Hu, M. -L.; He, S. L. Observation of multiphoton-induced fluorescence from graphene oxide nanoparticles and applications in in vivo functional bioimaging. Angew. Chem. Int. Ed. 2012, 51, 10570-10575.
Chien, C. -T.; Li, S. -S.; Lai, W. -J.; Yeh, Y. -C.; Chen, H. -A.; Chen, I. -S.; Chen, L. -C.; Chen, K. -H.; Nemoto, T.; Isoda, S. et al. Tunable photoluminescence from graphene oxide. Angew. Chem. Int. Ed. 2012, 51, 6662-6666.
Luo, Z. T.; Vora, P. M.; Mele, E. J.; Johnson, A. T. C.; Kikkawa, J. M. Photoluminescence and band gap modulation in graphene oxide. Appl. Phys. Lett. 2009, 94, 111909.
Galande, C.; Mohite, A. D.; Naumov, A. V.; Gao, W.; Ci, L. J.; Ajayan, A.; Gao, H.; Srivastava, A.; Weisman, R. B.; Ajayan, P. M. Quasi-molecular fluorescence from graphene oxide. Sci. Rep. 2011, 1, 85.
Shang, J. Z.; Ma, L.; Li, J. W.; Ai, W.; Yu, T.; Gurzadyan, G. G. The origin of fluorescence from graphene oxide. Sci. Rep. 2012, 2, 792.
Ritter, K. A.; Lyding, J. W. The influence of edge structure on the electronic properties of graphene quantum dots and nanoribbons. Nat. Mater. 2009, 8, 235-242.
Radovic, L. R.; Bockrath, B. On the chemical nature of graphene edges: Origin of stability and potential for magnetism in carbon materials. J. Am. Chem. Soc. 2005, 127, 5917-5927.
Xu, Q. F.; Zhou, Q.; Hua, Z.; Xue, Q.; Zhang, C. F.; Wang, X. Y.; Pan, D. Y.; Xiao, M. Single-particle spectroscopic measurements of fluorescent graphene quantum dots. ACS Nano 2013, 7, 10654-10661.
Jin, S. H.; Kim, D. H.; Jun, G. H.; Hong, S. H.; Jeon, S. Tuning the photoluminescence of graphene quantum dots through the charge transfer effect of functional groups. ACS Nano 2013, 7, 1239-1245.
Kumar, G. S.; Roy, R.; Sen, D.; Ghorai, U. K.; Thapa, R.; Mazumder, N.; Saha, S.; Chattopadhyay, K. K. Amino-functionalized graphene quantum dots: Origin of tunable heterogeneous photoluminescence. Nanoscale 2014, 6, 3384-3391.
Qian, Z. S.; Ma, J. J.; Shan, X. Y.; Shao, L. X.; Zhou, J.; Chen, J. R.; Feng, H. Surface functionalization of graphene quantum dots with small organic molecules from photoluminescence modulation to bioimaging applications: An experimental and theoretical investigation. RSC Adv. 2013, 3, 14571-14579.
Wang, L.; Wang, H. -Y.; Wang, Y.; Zhu, S. -J.; Zhang, Y. -L.; Zhang, J. -H.; Chen, Q. -D.; Han, W.; Xu, H. -L.; Yang, B. et al. Direct observation of quantum-confined graphene-like states and novel hybrid states in graphene oxide by transient spectroscopy. Adv. Mater. 2013, 25, 6539-6545.
Wang, L.; Zhu, S. -J.; Wang, H. -Y.; Wang, Y. -F.; Hao, Y. -W.; Zhang, J. -H.; Chen, Q. -D.; Zhang, Y. -L.; Han, W.; Yang, B. et al. Unraveling bright molecule-like state and dark intrinsic state in green-fluorescence graphene quantum dots via ultrafast spectroscopy. Adv. Opt. Mater. 2013, 1, 264-271.
Zhu, S. J.; Zhang, J. H.; Tang, S. J.; Qiao, C. Y.; Wang, L.; Wang, H. Y.; Liu, X.; Li, B.; Li, Y. F.; Yu, W. L. et al. Surface chemistry routes to modulate the photoluminescence of graphene quantum dots: From fluorescence mechanism to up-conversion bioimaging applications. Adv. Funct. Mater. 2012, 22, 4732-4740.
Mei, Q. S.; Zhang, Z. P. Photoluminescent graphene oxide ink to print sensors onto microporous membranes for versatile visualization bioassays. Angew. Chem. Int. Ed. 2012, 51, 5602-5606.
Liu, F.; Jang, M. -H.; Ha, H. D.; Kim, J. H.; Cho, Y. -H.; Seo, T. S. Facile synthetic method for pristine graphene quantum dots and graphene oxide quantum dots: Origin of blue and green luminescence. Adv. Mater. 2013, 25, 3657-3662.
Li, X. M.; Lau, S. P.; Tang, L. B.; Ji, R. B.; Yang, P. Z. Multicolour light emission from chlorine-doped graphene quantum dots. J. Mater. Chem. C 2013, 1, 7308-7313.
Luo, P. H.; Ji, Z.; Li, C.; Shi, G. Q. Aryl-modified graphene quantum dots with enhanced photoluminescence and improved pH tolerance. Nanoscale 2013, 5, 7361-7367.
Sun, H. J.; Gao, N.; Wu, L.; Ren, J. S.; Wei, W. L.; Qu, X. G. Highly photoluminescent amino-functionalized graphene quantum dots used for sensing copper ions. Chem. -Eur. J. 2013, 19, 13362-13368.
Feng, Y. Q.; Zhao, J. P.; Yan, X. B.; Tang, F. L.; Xue, Q. J. Enhancement in the fluorescence of graphene quantum dots by hydrazine hydrate reduction. Carbon 2014, 66, 334-339.
Sun, Y. Q.; Wang, S. Q.; Li, C.; Luo, P. H.; Tao, L.; Wei, Y.; Shi, G. Q. Large scale preparation of graphene quantum dots from graphite with tunable fluorescence properties. Phys. Chem. Chem. Phys. 2013, 15, 9907-9913.
Jiang, F.; Chen, D. Q.; Li, R. M.; Wang, Y. C.; Zhang, G. Q.; Li, S. M.; Zheng, J. P.; Huang, N. Y.; Gu, Y.; Wang, C. R. et al. Eco-friendly synthesis of size-controllable amine-functionalized graphene quantum dots with antimycoplasma properties. Nanoscale 2013, 5, 1137-1142.
Lingam, K.; Podila, R.; Qian, H. J.; Serkiz, S.; Rao, A. M. Evidence for edge-state photoluminescence in graphene quantum dots. Adv. Funct. Mater. 2013, 23, 5062-5065.
Chen, C. -F.; Park, C. -H.; Boudouris, B. W.; Horng, J.; Geng, B. S.; Girit, C.; Zettl, A.; Crommie, M. F.; Segalman, R. A.; Louie, S. G. et al. Controlling inelastic light scattering quantum pathways in graphene. Nature 2011, 471, 617-620.
Li, L. -S.; Yan, X. Colloidal graphene quantum dots. J. Phys. Chem. Lett. 2010, 1, 2572-2576.
Tomović, Z.; Watson, M. D.; Müllen, K. Superphenalene-based columnar liquid crystals. Angew. Chem. Int. Ed. 2004, 43, 755-758.
Mueller, M. L.; Yan, X.; Dragnea, B.; Li, L. -S. Slow hot-carrier relaxation in colloidal graphene quantum dots. Nano Lett. 2011, 11, 56-60.
Zhu, S. J.; Wang, L.; Li, B.; Song, Y. B.; Zhao, X. H.; Zhang, G. Y.; Zhang, S. T.; Lu, S. Y.; Zhang, J. H.; Wang, H. Y. et al. Investigation of photoluminescence mechanism of graphene quantum dots and evaluation of their assembly into polymer dots. Carbon 2014, 77, 462-472.
Kim, S.; Hwang, S. W.; Kim, M. -K.; Shin, D. Y.; Shin, D. H.; Kim, C. O.; Yang, S. B.; Park, J. H.; Hwang, E.; Choi, S. -H. et al. Anomalous behaviors of visible luminescence from graphene quantum dots: Interplay between size and shape. ACS Nano 2012, 6, 8203-8208.
Sk, M. A.; Ananthanarayanan, A.; Huang, L.; Lim, K. H.; Chen, P. Revealing the tunable photoluminescence properties of graphene quantum dots. J. Mater. Chem. C 2014, 2, 6954-6960.
Lui, C. H.; Mak, K. F.; Shan, J.; Heinz, T. F. Ultrafast photoluminescence from graphene. Phys. Rev. Lett. 2010, 105, 127404.
Kim, R.; Perebeinos, V.; Avouris, P. Relaxation of optically excited carriers in graphene. Phys. Rev. B 2011, 84, 075449.
Fuyuno, N.; Kozawa, D.; Miyauchi, Y.; Mouri, S.; Kitaura, R.; Shinohara, H.; Yasuda, T.; Komatsu, N.; Matsuda, K. Drastic change in photoluminescence properties of graphene quantum dots by chromatographic separation. Adv. Opt. Mater. 2014, 2, 983-989.
Tang, L. B.; Ji, R. B.; Li, X. M.; Teng, K. S.; Lau, S. P. Size-dependent structural and optical characteristics of glucose-derived graphene quantum dots. Part. Part. Syst. Charact. 2013, 30, 523-531.
Kwon, W.; Rhee, S. -W. Facile synthesis of graphitic carbon quantum dots with size tunability and uniformity using reverse micelles. Chem. Commun. 2012, 48, 5256-5258.
Kwon, W.; Lee, G.; Do, S.; Joo, T.; Rhee, S. -W. Size-controlled soft-template synthesis of carbon nanodots toward versatile photoactive materials. Small 2014, 10, 506-513.
Wang, X.; Cao, L.; Yang, S. -T.; Lu, F. S.; Meziani, M. J.; Tian, L. L.; Sun, K. W.; Bloodgood, M. A.; Sun, Y. -P. Bandgap-like strong fluorescence in functionalized carbon nanoparticles. Angew. Chem. Int. Ed. 2010, 49, 5310-5314.
Das, S. K.; Liu, Y. Y.; Yeom, S.; Kim, D. Y.; Richards, C. I. Single-particle fluorescence intensity fluctuations of carbon nanodots. Nano Lett. 2014, 14, 620-625.
Yu, P.; Wen, X. M.; Toh, Y. -R.; Tang, J. Temperature-dependent fluorescence in carbon dots. J. Phys. Chem. C 2012, 116, 25552-25557.
Wen, X. M.; Yu, P.; Toh, Y. -R.; Hao, X. T.; Tang, J. Intrinsic and extrinsic fluorescence in carbon nanodots: Ultrafast time-resolved fluorescence and carrier dynamics. Adv. Opt. Mater. 2013, 1, 173-178.
Wang, L.; Zhu, S. -J.; Wang, H. -Y.; Qu, S. -N.; Zhang, Y. -L.; Zhang, J. -H.; Chen, Q. -D.; Xu, H. -L.; Han, W.; Yang, B. et al. Common origin of green luminescence in carbon nanodots and graphene quantum dots. ACS Nano 2014, 8, 2541-2547.
Qu, S. N.; Wang, X. Y.; Lu, Q. P.; Liu, X. Y.; Wang, L. J. A biocompatible fluorescent ink based on water-soluble luminescent carbon nanodots. Angew. Chem. Int. Ed. 2012, 51, 12215-12218.
Sun, H. J.; Wu, L.; Gao, N.; Ren, J. S.; Qu, X. G. Improvement of photoluminescence of graphene quantum dots with a biocompatible photochemical reduction pathway and its bioimaging application. ACS Appl. Mater. Inter. 2013, 5, 1174-1179.
Li, L. -L.; Ji, J.; Fei, R.; Wang, C. -Z.; Lu, Q.; Zhang, J. -R.; Jiang, L. -P.; Zhu, J. -J. A facile microwave avenue to electrochemiluminescent two-color graphene quantum dots. Adv. Funct. Mater. 2012, 22, 2971-2979.
Krysmann, M. J.; Kelarakis, A.; Dallas, P.; Giannelis, E. P. Formation mechanism of carbogenic nanoparticles with dual photoluminescence emission. J. Am. Chem. Soc. 2012, 134, 747-750.
Song, Y. B.; Zhu, S. J.; Xiang, S. Y.; Zhao, X. H.; Zhang, J. H.; Zhang, H.; Fu, Y.; Yang, B. Investigation into the fluorescence quenching behaviors and applications of carbon dots. Nanoscale 2014, 6, 4676-4682.
Ding, D.; Goh, C. C.; Feng, G. X.; Zhao, Z. J.; Liu, J.; Liu, R. R.; Tomczak, N.; Geng, J. L.; Tang, B. Z.; Ng, L. G.; et al. Ultrabright organic dots with aggregation-induced emission characteristics for real-time two-photon intravital vasculature imaging. Adv. Mater. 2013, 25, 6083-6088.
Lai, T. T.; Zheng, E. H.; Chen, L. X.; Wang, X. Y.; Kong, L. C.; You, C. P.; Ruan, Y. M.; Weng, X. X. Hybrid carbon source for producing nitrogen-doped polymer nanodots: One-pot hydrothermal synthesis, fluorescence enhancement and highly selective detection of Fe(III). Nanoscale 2013, 5, 8015-8021.
Sun, Y.; Cao, W. P.; Li, S. L.; Jin, S. B.; Hu, K. L.; Hu, L. M.; Huang, Y. Y.; Gao, X. Y.; Wu, Y.; Liang, X. -J. Ultrabright and multicolorful fluorescence of amphiphilic polyethyleneimine polymer dots for efficiently combined imaging and therapy. Sci. Rep. 2013, 3, 3036.
Wu, C. F.; Chiu, D. T. Highly fluorescent semiconducting polymer dots for biology and medicine. Angew. Chem. Int. Ed. 2013, 52, 3086-3109.
Zhu, S. J.; Zhang, J. H.; Song, Y. B.; Zhang, G. Y.; Zhang, H.; Yang, B. Fluorescent nanocomposite based on PVA polymer dots. Acta Chim. Sinica 2012, 70, 2311-2315.
Sun, M.; Hong, C. -Y.; Pan, C. Y. A unique aliphatic tertiary amine chromophore: Fluorescence, polymer structure, and application in cell imaging. J. Am. Chem. Soc. 2012, 134, 20581-20584.
Zhu, Q.; Qiu, F.; Zhu, B. S.; Zhu, X. Y. Hyperbranched polymers for bioimaging. RSC Adv. 2013, 3, 2071-2083.
Hong, Y. N.; Lam, J. W. Y.; Tang, B. Z. Aggregation-induced emission: Phenomenon, mechanism and applications. Chem. Commun. 2009, 4332-4353.
Hong, Y. N.; Lam, J. W. Y.; Tang, B. Z. Aggregation-induced emission. Chem. Soc. Rev. 2011, 40, 5361-5388.
Mirtchev, P.; Henderson, E. J.; Soheilnia, N.; Yip, C. M.; Ozin, G. A. Solution phase synthesis of carbon quantum dots as sensitizers for nanocrystalline TiO2 solar cells. J. Mater. Chem. 2012, 22, 1265-1269.
Gupta, V.; Chaudhary, N.; Srivastava, R.; Sharma, G. D.; Bhardwaj, R.; Chand, S. Luminscent graphene quantum dots for organic photovoltaic devices. J. Am. Chem. Soc. 2011, 133, 9960-9963.
Zhang, X. Y.; Zhang, Y.; Wang, Y.; Kalytchuk, S.; Kershaw, S. V.; Wang, Y. H.; Wang, P.; Zhang, T. Q.; Zhao, Y.; Zhang, H. Z. et al. Color-switchable electroluminescence of carbon dot light-emitting diodes. ACS Nano 2013, 7, 11234-11241.
Shen, J. H.; Zhu, Y. H.; Yang, X. L.; Zong, J.; Zhang, J. M.; Li, C. Z. One-pot hydrothermal synthesis of graphene quantum dots surface-passivated by polyethylene glycol and their photoelectric conversion under near-infrared light. New J. Chem. 2012, 36, 97-101.
Liu, W. -W.; Feng, Y. -Q.; Yan, X. -B.; Chen, J. -T.; Xue, Q. -J. Superior micro-supercapacitors based on graphene quantum dots. Adv. Funct. Mater. 2013, 23, 4111-4122.
Lin, Z.; Xue, W.; Chen, H.; Lin, J. -M. Peroxynitrous-acid-induced chemiluminescence of fluorescent carbon dots for nitrite sensing. Anal. Chem. 2011, 83, 8245-8251.
Liu, J. -J.; Zhang, X. -L.; Cong, Z. -X.; Chen, Z. -T.; Yang, H. -H.; Chen, G. -N. Glutathione-functionalized graphene quantum dots as selective fluorescent probes for phosphate-containing metabolites. Nanoscale 2013, 5, 1810-1815.
Li, X.; Zhu, S. J.; Xu, B.; Ma, K.; Zhang, J. H.; Yang, B.; Tian, W. J. Self-assembled graphene quantum dots induced by cytochrome c: A novel biosensor for trypsin with remarkable fluorescence enhancement. Nanoscale 2013, 5, 7776-7779.
Tang, J.; Kong, B.; Wu, H.; Xu, M.; Wang, Y. C.; Wang, Y. L.; Zhao, D. Y.; Zheng, G. F. Carbon nanodots featuring efficient FRET for real-time monitoring of drug delivery and two-photon imaging. Adv. Mater. 2013, 25, 6569-6574.
Markovic, Z. M.; Ristic, B. Z.; Arsikin, K. M.; Klisic, D. G.; Harhaji-Trajkovic, L. M.; Todorovic-Markovic, B. M.; Kepic, D. P.; Kravic-Stevovic, T. K.; Jovanovic, S. P.; Milenkovic, M. M. et al. Graphene quantum dots as autophagy-inducing photodynamic agents. Biomaterials 2012, 33, 7084-7092.
Xie, Z.; Wang, F.; Liu, C. -Y. Organic-inorganic hybrid functional carbon dot gel glasses. Adv. Mater. 2012, 24, 1716-1721.
Zhang, G. Y.; Zhang, H.; Zhang, X. R.; Zhu, S. J.; Zhang, L.; Meng, Q. N.; Wang, M. Y.; Li, Y. F.; Yang, B. Embedding graphene nanoparticles into poly(N, N'-dimethylacrylamine) to prepare transparent nanocomposite films with high refractive index. J. Mater. Chem. 2012, 22, 21218-21224.