scholarly journals N,N′-bis(3-methylphenyl)-N,N′-dyphenylbenzidine Based Distributed Feedback Lasers with Holographically Fabricated Polymeric Resonators

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3843
Author(s):  
Víctor Bonal ◽  
José A. Quintana ◽  
José M. Villalvilla ◽  
Pedro G. Boj ◽  
Rafael Muñoz-Mármol ◽  
...  
Keyword(s):  
Blue Light ◽  
Uv Light ◽  
Distributed Feedback ◽  
Photo Oxidation ◽  
Deep Blue ◽  
Device Architecture ◽  
Hole Transporting ◽  
Pulsed Uv Light ◽  
Dichromated Gelatin ◽  
Index Contrast

The molecule N,N′-bis(3-methylphenyl)-N,N′-dyphenylbenzidine (TPD) has been widely used in optoelectronic applications, mainly for its hole-transporting properties, but also for its capability to emit blue light and amplified spontaneous emission, which is important for the development of organic lasers. Here, we report deep-blue-emitting distributed feedback (DFB) lasers based on TPD dispersed in polystyrene (PS), as active media, and dichromated gelatin layers with holographically engraved relief gratings, as laser resonators. The effect of the device architecture (with the resonator located below or on top of the active layer) is investigated with a dye (TPD) that can be doped into PS at higher rates (up to 60 wt%), than with previously used dyes (<5 wt%). This has enabled changing the index contrast between film and resonator, which has an important effect on the laser performance. With regards to thresholds, both architectures behave similarly for TPD concentrations above 20 wt%, while for lower concentrations, top-layer resonator devices show lower values (around half). Remarkably, the operational durability of top-layer resonator devices is larger (in a factor of around 2), independently of the TPD concentration. This is a consequence of the protection offered by the resonator against dye photo-oxidation when the device is illuminated with pulsed UV light.

Bis(4-diphenylaminophenyl)carbazole end-capped fluorene as solution-processed deep-blue light-emitting and hole-transporting materials for electroluminescent devices

2012 ◽  
Vol 53 (28) ◽  
pp. 3615-3618 ◽  
Author(s):  
Daungratchaneekron Meunmart ◽  
Narid Prachumrak ◽  
Tinnagon Keawin ◽  
Siriporn Jungsuttiwong ◽  
Taweesak Sudyoadsuk ◽  
...  
Keyword(s):  
Blue Light ◽  
Solution Processed ◽  
Electroluminescent Devices ◽  
Light Emitting ◽  
Deep Blue ◽  
Hole Transporting ◽  
Hole Transporting Materials

scholarly journals Effect of Pre-Harvest Supplemental UV-A/Blue and Red/Blue LED Lighting on Lettuce Growth and Nutritional Quality

Horticulturae ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 80
Author(s):  
Triston Hooks ◽  
Joseph Masabni ◽  
Ling Sun ◽  
Genhua Niu
Keyword(s):  
Blue Light ◽  
Nutritional Quality ◽  
Uv Light ◽  
Ultra Violet ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Daily Light Integral ◽  
Lettuce Growth ◽  
Supplemental Lighting

Blue light and ultra-violet (UV) light have been shown to influence plant growth, morphology, and quality. In this study, we investigated the effects of pre-harvest supplemental lighting using UV-A and blue (UV-A/Blue) light and red and blue (RB) light on growth and nutritional quality of lettuce grown hydroponically in two greenhouse experiments. The RB spectrum was applied pre-harvest for two days or nights, while the UV-A/Blue spectrum was applied pre-harvest for two or four days or nights. All pre-harvest supplemental lighting treatments had a same duration of 12 h with a photon flux density (PFD) of 171 μmol m−2 s−1. Results of both experiments showed that pre-harvest supplemental lighting using UV A/Blue or RB light can increase the growth and nutritional quality of lettuce grown hydroponically. The enhancement of lettuce growth and nutritional quality by the pre-harvest supplemental lighting was more effective under low daily light integral (DLI) compared to a high DLI and tended to be more effective when applied during the night, regardless of spectrum.

scholarly journals Enhanced Crystallinity and Luminescence Characteristics of Hexagonal Boron Nitride Doped with Cerium Ions According to Tempering Temperatures

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 193
Author(s):  
Jae Yong Jung ◽  
Juna Kim ◽  
Yang Do Kim ◽  
Young-Kuk Kim ◽  
Hee-Ryoung Cha ◽  
...  
Keyword(s):  
Rare Earth ◽  
Boron Nitride ◽  
Uv Light ◽  
Hexagonal Boron Nitride ◽  
Heating Temperature ◽  
Blue Emission ◽  
Deep Blue ◽  
Cerium Ion ◽  
Luminescence Characteristics ◽  
Enhanced Crystallinity

Hexagonal boron nitride was synthesized by pyrolysis using boric acid and melamine. At this time, to impart luminescence, rare earth cerium ions were added to synthesize hexagonal boron nitride nanophosphor particles exhibiting deep blue emission. To investigate the changes in crystallinity and luminescence according to the re-heating temperature, samples which had been subjected to pyrolysis at 900 °C were subjected to re-heating from 1100 °C to 1400 °C. Crystallinity and luminescence were enhanced according to changes in the reheating temperature. The synthesized cerium ion-doped hexagonal boron nitride nanoparticle phosphor was applied to the anti-counterfeiting field to prepare an ink that can only be identified under UV light.

Deep‐blue light‐emitting polyfluorenes with asymmetrical naphthylthio‐fluorene as Chromophores

2018 ◽  
Vol 57 (2) ◽  
pp. 171-182 ◽  
Author(s):  
Liwen Hu ◽  
Zhonglian Wu ◽  
Xiaojun Wang ◽  
Yawei Ma ◽  
Ting Guo ◽  
...  
Keyword(s):  
Blue Light ◽  
Light Emitting ◽  
Deep Blue
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