scholarly journals Insight into the photophysics of strong dual emission (blue & green) producing graphene quantum dot clusters and their application towards selective and sensitive detection of trace level Fe3+ and Cr6+ ions

RSC Advances ◽  
2020 ◽  
Vol 10 (45) ◽  
pp. 26613-26630
Author(s):  
Ganapathi Bharathi ◽  
Devaraj Nataraj ◽  
Sellan Premkumar ◽  
Padmanaban Saravanan ◽  
Daniel T. Thangadurai ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Trace Level ◽  
Dual Emission ◽  
Schematic Representation ◽  
Graphene Quantum Dot ◽  
Pl Emission ◽  
Cluster Type ◽  
Insight Into ◽  
Strong Dual ◽  
Type Sample

Schematic representation for the origin of blue and green emissions, and the resultant PL emission spectra from the GQD interconnected cluster-type sample.

scholarly journals Light Emission by Nanoporous GaN Produced by a Top-Down, Nonlithographical Nanopatterning

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
E. Kheirandish ◽  
N. A. Kouklin ◽  
J. Liang
Keyword(s):  
Light Emission ◽  
Electronic Devices ◽  
Emission Spectra ◽  
Temperature Dependent ◽  
Physical Mechanisms ◽  
Spectral Shifts ◽  
Nanopore Arrays ◽  
Bulk Gan ◽  
Pl Emission ◽  
Temperature Dependent Photoluminescence

Temperature-dependent photoluminescence (PL) spectroscopy is carried out to probe radiative recombination and related light emission processes in two-dimensional periodic close-packed nanopore arrays in gallium nitride (np-GaN). The arrays were produced by nonlithographic nanopatterning of wurtzite GaN followed by a dry etching. The results of Raman spectroscopy point to a small relaxation of the compressive stress of ~0.24 GPa in nanoporous vs. bulk GaN. At ~300 K, the PL emission is induced by excitons and not free-carrier interband radiative recombinations. An evolution of the emission spectra with T is confirmed to be mainly a result of a decay of nonexcitonic PL emission and less of spectral shifts of the underlying PL bands. A switching of excitonic PL regime observed experimentally was analyzed within the exciton recombination-generation framework. The study provides new insights into the behaviors and physical mechanisms regulating light emission processes in np-GaN, critical to the development of nano-opto-electronic devices based on mesoscopic GaN.

scholarly journals Strong dual emission in covalent organic frameworks induced by ESIPT

2019 ◽  
Vol 10 (48) ◽  
pp. 11103-11109 ◽  
Author(s):  
Hua-Qing Yin ◽  
Fangfei Yin ◽  
Xue-Bo Yin
Keyword(s):  
Hydroxyl Groups ◽  
Covalent Organic Frameworks ◽  
Dual Emission ◽  
Strong Dual

The introduction of hydroxyl groups and n-butyl groups into COF-4-OH for the construction of COFs with strong dual emission was demonstrated.

Photo and Electroluminescent Properties of a Porphyrin-Poly(p-Phenylene Vinylene) Derivative

1999 ◽  
Vol 598 ◽  
Author(s):  
J. Morgado ◽  
R. Iqbal ◽  
G. Yahioglu ◽  
L. R. Milgrom ◽  
S. C. Moratti ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Solid State ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Phenylene Vinylene ◽  
Efficient Energy Transfer ◽  
Light Emitting ◽  
Efficient Energy ◽  
Small Absorption ◽  
Pl Emission

ABSTRACTThe solid state luminescent properties of new statistical copolymers of 2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene and a porphyrin-substituted phenylene vinylene are reported. The photoluminescence, PL, emission shows an efficient energy transfer to the porphyrin, in spite of the small absorption coefficient of the porphyrin in the wavelength range of the poly [2-methoxy-5-(2'- ethylhexyloxy)-1,4-phenylene vinylene], MEH-PPV, emission. At a porphyrin content of 0.25%, by weight, the emission is already dominated by the porphyrin. The PL efficiency of these copolymers is significantly reduced from the value of 13% for MEH-PPV down to 3% for the copolymer with 10.84% of porphyrin. Efficient energy transfer is also observed in the emission spectra of light-emitting diodes.

Tunable dual emission of Ca3Al4ZnO10:Bi3+,Mn4+via energy transfer for indoor plant growth lighting

2018 ◽  
Vol 6 (33) ◽  
pp. 8914-8922 ◽  
Author(s):  
Zhi Zhou ◽  
Yuan Zhong ◽  
Mao Xia ◽  
Nan Zhou ◽  
Bingfu Lei ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Plant Growth ◽  
Absorption Spectra ◽  
Emission Spectra ◽  
Plant Pigments ◽  
Dual Emission ◽  
Co Doped

The emission spectra of Bi3+ and Mn4+ co-doped Ca3Al4ZnO10 phosphors match well with the absorption spectra of plant pigments for indoor plant growth lighting.

DIELECTRIC AND OPTICAL BEHAVIOR OF STRONTIUM DOPED TiO2 SYNTHESIZED BY SOLID STATE REACTION METHOD

2013 ◽  
Vol 22 ◽  
pp. 336-339
Author(s):  
M. H. MANGROLA ◽  
V. G. JOSHI ◽  
B. H. PARMAR ◽  
A. S. PILLAI
Keyword(s):  
Solid State ◽  
Solid State Reaction ◽  
Emission Spectra ◽  
Solid State Reaction Method ◽  
Excitation Wavelength ◽  
Solid State Reaction Technique ◽  
Dielectric Constant And Loss ◽  
Pl Emission ◽  
Optical Applications ◽  
Optical Behavior

In the present study, Strontium doped Titanium Dioxide (TiO2) were synthesized by standard solid-state reaction technique. The dielectric property of the synthesized samples has been studied in the present work. The dielectric constant and loss have been measured as a function of frequency (100 Hz-1 KHz) and temperature (50°C to 300°C). Strontium doped TiO2 shows interesting optical properties promising a variety of optical applications. Photoluminescence (PL) spectra was obtained at different excitation wavelength. PL emission spectra show that positions of PL peaks gradually shifts towards the violet region with increase of Sr ion dosage from 3% to 5%. The results are discussed in details.

Organic Syntheses and Characteristics of Novel Conjugated Polymers for AMOLEDs

2010 ◽  
Vol 75 ◽  
pp. 91-96
Author(s):  
Su Hee Song ◽  
Young Eup Jin ◽  
Joo Young Shim ◽  
Kwang Hee Lee ◽  
Hong Suk Suh
Keyword(s):  
Conjugated Polymers ◽  
Blue Emission ◽  
Wavelength Region ◽  
Emission Spectra ◽  
Polymer Backbone ◽  
Light Emitting ◽  
Long Wavelength ◽  
New Class ◽  
Solid Thin Films ◽  
Pl Emission

Conjugated polymers with a stabilized blue emission are of importance for the realization of large flat panel AMOLED displays using polymer light-emitting diodes. Several novel conjugated polymers using newly developed templates for the stabilized EL emission are reported. Poly(2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene)) (PCPP) is a new class of blue-emitting polymers utilizing a new back-bone. This material emits a efficient blue EL without exhibiting any unwanted peak in the long wavelength region (green region) even after prolonged annealing at an elevated temperature of 150oC in air, or operation of the device. New electroluminescent spiro-PCPPs, poly((2,6-(3',6'-bis(2-ethylhexyloxy)-spiro(4H-cyclopenta[def] phenanthrene-4,9'-[9H]fluorene)))-alt-(2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopenta[def]phenanthrene))) (spiro-PCPP-alt-PCPP) and poly((2,6-(3',6'-bis(2-ethylhexyloxy)-spiro(4H-cyclopenta[def] phenanthrene-4,9'-[9H]fluorene)))-alt-(1,4-phenylene)) (spiro-PCPPP), have been synthesized by the Suzuki polymerization. The PL emission spectra of polymers in THF solution show a same maximum peak at 397 nm. The maximum PL emission spectra of polymers appeared at around 463 and 456 nm in solid state, respectively. The PL spectra in solid thin films show more red-shifted over 60 nm than solution conditions. The blue emissions at 400-409 nm for the π–π* transitions of conjugated polymer backbone are almost completely quenched or decreased.

scholarly journals Photoluminescence and Electrochemiluminescence of Thermally Activated Delayed Fluorescence (TADF) Emitters Containing Diphenylphosphine Chalcogenide-Substituted Carbazole Donors

2021 ◽  
Author(s):  
Shiv Kumar ◽  
Pauline Tourneur ◽  
Jonathan Adsetts ◽  
Michael Wong ◽  
Pachaiyappan Rajamalli ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Delayed Fluorescence ◽  
Thermally Activated Delayed Fluorescence ◽  
Thermally Activated ◽  
Polar Media ◽  
Delay Times ◽  
Derivatives Of ◽  
Homo Lumo ◽  
Rising Time ◽  
Insight Into

Aiming to develop efficient blue-emitting thermally activated delayed fluorescence (TADF) compounds, we have designed and synthesized derivatives of the well-known sky-blue emitter 2CzPN that contain electron-accepting phosphine chalcogenide groups to stabilize the HOMO level relative to the pristine compound, thus increasing the HOMO-LUMO gap and blue-shifting the emission wavelength. By cyclic voltammetry, photophysical data and quantum-chemical calculations, it was found that polar solvents and matrices validated the proposed concept, but these trends were not recovered in non-polar media. The suitability of these 2CzPN derivatives in polar matrices for optoelectronic applications was explored with electrochemiluminescence (ECL) by measuring emission delays, radical stability, emission stabilities, emission efficiencies and emission spectra. Some of the 2CzPN derivatives showed an unprecedented delayed onset of the ECL, and delayed rising time to the ECL maximum, as well as long ECL emission decay. All of these mentioned delay times suggest that these luminophores primarily emit via organic long-persistent electrochemiluminescence (OLECL) mechanisms. The derivatization of the donor groups of the emitters affected both the radical stability and the predominant emission mechanism, providing important insight into their potential as emitters in solid-state electroluminescent devices.

Effect of co-doping of alkali metal ions on Ca0.5RE1−x(MoO4)2:xEu3+ (RE = Y, La) phosphors with enhanced luminescence properties

RSC Advances ◽  
2016 ◽  
Vol 6 (84) ◽  
pp. 80390-80397 ◽  
Author(s):  
Venkatakrishnan Mahalingam ◽  
Jagannathan Thirumalai
Keyword(s):  
Alkali Metal ◽  
Metal Ions ◽  
Emission Spectra ◽  
Luminescence Properties ◽  
Alkali Metal Ions ◽  
Elemental Mapping ◽  
Co Doping ◽  
Pl Emission ◽  
Enhanced Luminescence

Illustration of elemental mapping and PL emission spectra of the phosphors, Ca0.5RE1−x(MoO4)2:Eu3+,M+ (RE = Y, La; M = Li, K and Na).

scholarly journals Outstanding Photoluminescence in Pr3+-Doped Perovskite Ceramics

Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 419
Author(s):  
Jiameng Zhang ◽  
Yanan Hao ◽  
Meihua Bi ◽  
Guoyan Dong ◽  
Xiaoming Liu ◽  
...  
Keyword(s):  
Emission Spectra ◽  
Green Emission ◽  
Emission Peak ◽  
Ferroelectric Ceramics ◽  
X Ray Diffraction ◽  
Green Band ◽  
Conventional Solid State Reaction ◽  
X Ray ◽  
Application Range ◽  
Pl Emission

Ba (Zr0.2Ti0.8) O3-50% (Ba0.7Ca0.3) TiO3 (BZT-0.5BCT) ceramics with different doping contents of Pr3+ were prepared by the conventional solid-state reaction. The phase structure and crystallinity of the fabricated ceramics were investigated by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Photoluminescence (PL) emission spectra were measured to analyze the PL characteristics. The strong intensities of a green band at 489 nm and a red band at 610 nm were observed. The maximum emission intensity of the PL spectrum was achieved in the BZT-0.5BCT ceramic with 0.2% mol of Pr3+ ions. Furthermore, the PL spectra of BZT-0.5BCT ceramics were found to be sensitive to polarization of the ferroelectric ceramics. Compared with the unpoled ceramics, the green emission increased about 42% and a new emission peak at 430 nm appeared for the poled ceramics. With excellent intrinsic ferroelectricity and an enhanced PL property, such material has potential to realize multifunctionality in a wide application range.

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