Compact optical detector utilizing light emitting diodes, 50 nL L-shaped silica capillary cell and CCD spectrometer for simultaneous multi-wavelength monitoring of absorbance and fluorescence in microcolumn liquid chromatography

Abstract To achieve a better understanding of accumulation of paclitaxel and related taxanes in Himalayan yew (Taxus wallichiana Zucc.) callus mass, induction and growth of calli from needles and petioles under light-emitting diodes (LEDs) and production of paclitaxel and baccatin were investigated. Calli were induced from needles and petioles on Gamborg's B5 medium supplemented with 1 mg·l-1 kinetin and 4 mg·l-1 2,4-D under different com-binations of blue and red LEDs. Calli were further cultured in that medium under the same lighting conditions. Callus induction from needles and petioles and growth was better under blue LEDs than under red LEDs and fluorescent light. The combinations of blue and red LEDs produced variable results. The paclitaxel content of these calli was quantified by high-performance liquid chromatography. The paclitaxel content of calli derived from needles was 0.00628% and the 10-DAB (10-Deacetylbaccatin III) content was 0.00366%. The paclitaxel content of calli derived from petioles was 0.00412%, and no 10-DAB was detected.

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Tea quality and classification evaluation using multi-wavelength light-emitting diodes induced fluorescence spectroscopy

10.1117/12.2004479 ◽

2013 ◽

Cited By ~ 1

Author(s):

Chao Feng ◽

Xuan Liu ◽

Chunsheng Yan ◽

Sailing He ◽

Liang Mei

Keyword(s):

Fluorescence Spectroscopy ◽

Light Emitting Diodes ◽

Light Emitting ◽

Tea Quality ◽

Multi Wavelength ◽

Classification Evaluation ◽

Wavelength Light

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Influence of the Carrier Mobility and Charge Accumulation in Interfacial Layers on Deterioration in Organic Light-emitting Diodes

IEEJ Transactions on Fundamentals and Materials ◽

10.1541/ieejfms.137.291 ◽

2017 ◽

Vol 137 (5) ◽

pp. 291-297

Author(s):

Hirofumi Nakamura ◽

Miki Kuribayashi ◽

Chihaya Adachi

Keyword(s):

Carrier Mobility ◽

Light Emitting Diodes ◽

Organic Light Emitting Diodes ◽

Charge Accumulation ◽

Light Emitting ◽

Interfacial Layers ◽

Organic Light

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Injecting Inter-Layers and the Built-in Potential of Blue Polymer Light-Emitting Diodes

MRS Proceedings ◽

10.1557/proc-660-jj6.9 ◽

2000 ◽

Vol 660 ◽

Author(s):

Thomas M. Brown ◽

Ian S. Millard ◽

David J. Lacey ◽

Jeremy H. Burroughes ◽

Richard H. Friend ◽

...

Keyword(s):

Indium Tin Oxide ◽

Light Emitting Diodes ◽

Basic Structure ◽

Thin Layers ◽

Carrier Injection ◽

Semiconducting Polymer ◽

Light Emitting ◽

Physical Mechanisms ◽

Organic Solid ◽

Polymer Light Emitting Diodes

ABSTRACTThe semiconducting-polymer/injecting-electrode heterojunction plays a crucial part in the operation of organic solid state devices. In polymer light-emitting diodes (LEDs), a common fundamental structure employed is Indium-Tin-Oxide/Polymer/Al. However, in order to fabricate efficient devices, alterations to this basic structure have to be carried out. The insertion of thin layers, between the electrodes and the emitting polymer, has been shown to greatly enhance LED performance, although the physical mechanisms underlying this effect remain unclear. Here, we use electro-absorption measurements of the built-in potential to monitor shifts in the barrier height at the electrode/polymer interface. We demonstrate that the main advantage brought about by inter-layers, such as poly(ethylenedioxythiophene)/poly(styrene sulphonic acid) (PEDOT:PSS) at the anode and Ca, LiF and CsF at the cathode, is a marked reduction of the barrier to carrier injection. The electro- absorption results also correlate with the electroluminescent characteristics of the LEDs.

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Low-Temperature Operation of Green, Blue and UV InGaN/GaN Multiple-Quantum-Well Light-Emitting Diodes

MRS Proceedings ◽

10.1557/proc-764-c5.5 ◽

2003 ◽

Vol 764 ◽

Author(s):

X. A. Cao ◽

S. F. LeBoeuf ◽

J. L. Garrett ◽

A. Ebong ◽

L. B. Rowland ◽

...

Keyword(s):

Quantum Well ◽

Light Emitting Diodes ◽

Multiple Quantum Well ◽

Light Output ◽

Localized States ◽

Multiple Quantum ◽

Nonradiative Recombination ◽

Light Emitting ◽

Temperature Range ◽

Green Leds

Absract:Temperature-dependent electroluminescence (EL) of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs) with peak emission energies ranging from 2.3 eV (green) to 3.3 eV (UV) has been studied over a wide temperature range (5-300 K). As the temperature is decreased from 300 K to 150 K, the EL intensity increases in all devices due to reduced nonradiative recombination and improved carrier confinement. However, LED operation at lower temperatures (150-5 K) is a strong function of In ratio in the active layer. For the green LEDs, emission intensity increases monotonically in the whole temperature range, while for the blue and UV LEDs, a remarkable decrease of the light output was observed, accompanied by a large redshift of the peak energy. The discrepancy can be attributed to various amounts of localization states caused by In composition fluctuation in the QW active regions. Based on a rate equation analysis, we find that the densities of the localized states in the green LEDs are more than two orders of magnitude higher than that in the UV LED. The large number of localized states in the green LEDs are crucial to maintain high-efficiency carrier capture at low temperatures.

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