Toward a new generation of white phosphors for solid state lighting using glassy yttrium aluminoborates

2015 ◽  
Vol 3 (22) ◽  
pp. 5795-5802 ◽  
Author(s):  
Vinicius Ferraz Guimarães ◽  
Lauro J. Q. Maia ◽  
Isabelle Gautier-Luneau ◽  
Christophe Bouchard ◽  
Antonio Carlos Hernandes ◽  
...  

We present a new family of highly emissive white phosphors.

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1666 ◽  
Author(s):  
Issac Torres ◽  
Mauro Ruiz ◽  
Hung Phan ◽  
Noemi Dominguez ◽  
Jacobo Garcia ◽  
...  

Organic semiconductor materials composed of π–π stacking aromatic compounds have been under intense investigation for their potential uses in flexible electronics and other advanced technologies. Herein we report a new family of seven π–π stacking compounds of silver(I) bis-N-(4-pyridyl) benzamide with varying counterions, namely [Ag(NPBA)2]X, where NPBA is N-(4-pyridyl) benzamine, X = NO3− (1), ClO4− (2), CF3SO3− (3), PF6− (4), BF4− (5), CH3PhSO3− (6), and PhSO3− (7), which form extended π−π stacking networks in one-dimensional (1D), 2D and 3D directions in the crystalline solid-state via the phenyl moiety, with average inter-ring distances of 3.823 Å. Interestingly, the counterions that contain π–π stacking-capable groups, such as in 6 and 7, can induce the formation of mesomorphic phases at 130 °C in dimethylformamide (DMF), and can generate highly branched networks at the mesoscale. Atomic force microscopy studies showed that 2D interconnected fibers form right after nucleation, and they extend from ~30 nm in diameter grow to reach the micron scale, which suggests that it may be possible to stop the process in order to obtain nanofibers. Differential scanning calorimetry studies showed no remarkable thermal behavior in the complexes in the solid state, which suggests that the mesomorphic phases originate from the mechanisms that occur in the DMF solution at high temperatures. An all-electron level simulation of the band gaps using NRLMOL (Naval Research Laboratory Molecular Research Library) on the crystals gave 3.25 eV for (1), 3.68 eV for (2), 1.48 eV for (3), 5.08 eV for (4), 1.53 eV for (5), and 3.55 eV for (6). Mesomorphic behavior in materials containing π–π stacking aromatic interactions that also exhibit low-band gap properties may pave the way to a new generation of highly branched organic semiconductors.


2016 ◽  
Author(s):  
V. F. Guimarães ◽  
P. Burner ◽  
L. J. Q. Maia ◽  
A. Ferrier ◽  
B. Viana ◽  
...  

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 758
Author(s):  
Ching-Cherng Sun ◽  
Shih-Hsin Ma ◽  
Quang-Khoi Nguyen

Light-emitting diodes (LEDs) have been intensively studied for white-light lighting since their luminous efficacy exceeds 50 lm/W. Currently, the luminous efficacy of an LED light tube/bulb is almost above 100 lm/W. LED solid-state lighting (SSL) has unequivocally become the major light source in general lighting. The fact of high efficiency and other advantages of LED SSL is enough to penetrate all lighting scenarios. However, what people demand from new-generation lighting is not only in energy efficiency but also in lighting quality. Thus, how to make the lighting more user friendly is one of the important issues, and, here, optics is the key point. For making a collection with the discussions of the novel optical design in enhancing lighting efficiency in a more uniform illumination pattern, in higher sharpness for special lighting, in a higher signal-to-noise ratio for communication, in more functions for new applications, etc., this Special Issue of “Advanced LED Solid-State Lighting Optics” focuses on advanced applications in all aspects.


2015 ◽  
Author(s):  
Norman Bardsley ◽  
Stephen Bland ◽  
Monica Hansen ◽  
Lisa Pattison ◽  
Morgan Pattison ◽  
...  

CrystEngComm ◽  
2020 ◽  
Vol 22 (26) ◽  
pp. 4438-4448 ◽  
Author(s):  
Dongxun Chen ◽  
Liangliang Zhang ◽  
Yanjie Liang ◽  
Weili Wang ◽  
Shao Yan ◽  
...  

Bi2SiO5:Yb3+,Er3+ yolk–shell nanophosphors have been successfully synthesized, which are expected to find important applications in optical thermometry and solid-state lighting.


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