Facile synthesis of yellow fluorescent carbon dots for highly sensitive sensing of cobalt ions and biological imaging

2019 ◽  
Vol 11 (32) ◽  
pp. 4077-4083 ◽  
Author(s):  
Min Tian ◽  
Yaoming Liu ◽  
Yingte Wang ◽  
Yong Zhang

Long-wavelength light emission has been garnering extensive attention in terms of strong tissue penetration ability and weak light scattering effects.

2005 ◽  
Vol 86 (14) ◽  
pp. 143108 ◽  
Author(s):  
H. Y. Liu ◽  
M. J. Steer ◽  
T. J. Badcock ◽  
D. J. Mowbray ◽  
M. S. Skolnick ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Heechan Kim ◽  
Woojin Park ◽  
Younghun Kim ◽  
Michael Filatov ◽  
Cheol Ho Choi ◽  
...  

AbstractIt is commonly accepted that a large π-conjugated system is necessary to realize low-energy electronic transitions. Contrary to this prevailing notion, we present a new class of light-emitters utilizing a simple benzene core. Among different isomeric forms of diacetylphenylenediamine (DAPA), o- and p-DAPA are fluorescent, whereas m-DAPA is not. Remarkably, p-DAPA is the lightest (FW = 192) molecule displaying red emission. A systematic modification of the DAPA system allows the construction of a library of emitters covering the entire visible color spectrum. Theoretical analysis shows that their large Stokes shifts originate from the relief of excited-state antiaromaticity, rather than the typically assumed intramolecular charge transfer or proton transfer. A delicate interplay of the excited-state antiaromaticity and hydrogen bonding defines the photophysics of this new class of single benzene fluorophores. The formulated molecular design rules suggest that an extended π-conjugation is no longer a prerequisite for a long-wavelength light emission.


2008 ◽  
Vol 103 (9) ◽  
pp. 094315 ◽  
Author(s):  
Zhiqiang Zhou ◽  
Yingqiang Xu ◽  
Ruiting Hao ◽  
Bao Tang ◽  
Zhengwei Ren ◽  
...  

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Ye Yu ◽  
Tao Wang ◽  
Xiufang Chen ◽  
Lidong Zhang ◽  
Yang Wang ◽  
...  

AbstractStrain modulation is crucial for heteroepitaxy such as GaN on foreign substrates. Here, the epitaxy of strain-relaxed GaN films on graphene/SiC substrates by metal-organic chemical vapor deposition is demonstrated. Graphene was directly prepared on SiC substrates by thermal decomposition. Its pre-treatment with nitrogen-plasma can introduce C–N dangling bonds, which provides nucleation sites for subsequent epitaxial growth. The scanning transmission electron microscopy measurements confirm that part of graphene surface was etched by nitrogen-plasma. We study the growth behavior on different areas of graphene surface after pre-treatment, and propose a growth model to explain the epitaxial growth mechanism of GaN films on graphene. Significantly, graphene is found to be effective to reduce the biaxial stress in GaN films and the strain relaxation improves indium-atom incorporation in InGaN/GaN multiple quantum wells (MQWs) active region, which results in the obvious red-shift of light-emitting wavelength of InGaN/GaN MQWs. This work opens up a new way for the fabrication of GaN-based long wavelength light-emitting diodes.


Author(s):  
Jonathan B. Grimm ◽  
Ariana N. Tkachuk ◽  
Heejun Choi ◽  
Boaz Mohar ◽  
Natalie Falco ◽  
...  

ABSTRACTExpanding the palette of fluorescent dyes is vital for pushing the frontier of biological imaging. Although rhodamine dyes remain the premier type of small-molecule fluorophore due to their bioavailability and brightness, variants excited with far-red or near-infrared light suffer from poor performance due to their propensity to adopt a lipophilic, nonfluorescent form. We report a general chemical modification for rhodamines that optimizes long-wavelength variants and enables facile functionalization with different chemical groups.


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