Effect of Different Catalysts and Growth Temperature on the Photoluminescence Properties of Zinc Silicate Nanostructures Grown via VLS Method

2021 ◽  
Author(s):  
Ghfoor Muhammad ◽  
Imran Murtaza ◽  
Rehan Abid ◽  
Naeem Ahmad
Keyword(s):  
Energy Levels ◽  
Visible Region ◽  
Wide Bandgap ◽  
Visible Spectral Range ◽  
Zinc Silicate ◽  
Band Spectrum ◽  
Photoluminescence Properties ◽  
Display Devices ◽  
Crystal Growth Kinetics ◽  
Potential Applications

Abstract Herein, we explore the photoluminescence properties of zinc silicate (Zn2SiO4) nanostructures synthesized by vapor-liquid-solid (VLS) mode of growth using three different catalysts (Sn, Ag and Mn). Different catalysts significantly influence the growth rate which in turn has an impact on the structure and hence the photoluminescence of the prepared zinc silicate nanostructures. Zn2SiO4 has a wide bandgap of about 5.5 eV and in its pure form, it does not emit in visible region due to its inner shell electronic transitions between the 3d5 energy levels. However, the incorporation of different catalysts (Sn, Ag and Mn) at different growth temperatures into the Zn2SiO4 crystal growth kinetics provides wide visible spectral range of photoluminescence (PL) emissions. PL analysis shows broad multi-band spectrum in the visible region and distinct colours (red, yellow, green, blue, cyan and violet) are obtained depending on the crystalline structure of the prepared nanostructures. The allowed transitions due to the effect of different catalysts on zinc silicate lattice offer a huge cross-section of absorption that generates strong photoluminescence. The correlation between the structural and optical properties of the synthesized nanostructures is discussed in detail. The synthesized photoluminescent nanostructures have potential applications in solid-state lighting and display devices.

Enhanced Electroluminescence of Urethane Containing Processable Polythiophene Derivative by Addition of Dye Molecules

2000 ◽  
Vol 660 ◽  
Author(s):  
Amarjeet Kaur ◽  
Mario J. Cazeca ◽  
Kethinni G. Chittibabu ◽  
Jayant Kumar ◽  
Sukant K. Tripathy
Keyword(s):  
Fluorescent Dyes ◽  
Visible Region ◽  
Dye Molecules ◽  
Flat Panel Display ◽  
Large Area ◽  
Good Efficiency ◽  
Display Devices ◽  
Yellow Color ◽  
Organic Electroluminescent ◽  
Important Approach

ABSTRACTOrganic electroluminescent (EL) diodes based on fluorescent dyes and conducting polymers have attracted the interest of researchers, mainly because of their emission in the visible region and for application to large area portable flat panel display devices, driven at low voltages. Therefore, for the development of higher efficiency polymer EL diodes, the optimal combination of the merits of organic fluorescent dye molecules with that of conjugated polymer is an important approach. We report electroluminescence studies of polymer light emitting diodes (p-LEDs) fabricated with poly[2-(3-thienyl)ethanol n-butoxy carbonylmethyl urethane] (PURET) and its composite with 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H pyran (DCM) dye. These materials have been chosen in view of the fact that PURET exhibits a small overlap between emission and absorption spectra whereas DCM has a good efficiency of trapping both electrons as well as holes. Polyaniline has been utilized as hole injecting layer whereas tris-8-hydroxyquinoline-aluminum as electron injecting layer. Enhanced electroluminescence with bright yellow color has been observed in p-LEDs by the addition of dye.

scholarly journals The ultra-violet spectrum of magnesium hydride. 1.—The band at λ 2430

1929 ◽  
Vol 122 (790) ◽  
pp. 442-455 ◽  
Keyword(s):  
Fine Structure ◽  
General Structure ◽  
Energy Levels ◽  
Visible Region ◽  
Ultra Violet ◽  
Present Theory ◽  
Magnesium Hydride ◽  
Electronic Energy ◽  
Band Spectra ◽  
Electronic Energy Levels

The system of bands in the visible region of the emission spectrum of magnesium hydride is now well known. The bands with heads at λλ 5622, 5211, 4845 were first measured by Prof. A. Fowler, who arranged many of the strongest lines in empirical series for identification with absorption lines in the spectra of sun-spots. Later, Heurlinger rearranged these series in the now familiar form of P, Q and R branches, and considered them, with the OH group, as typical of doublet systems in his classification of the fine structure of bands. More recently, W. W. Watson and P. Rudnick have remeasured these bands, using the second order of a 21-foot concave grating, and have carried out a further investigation of the fine structure in the light of the present theory of band spectra. Their detection of an isotope effect of the right order of magnitude, considered with the general structure of the system, and the experimental work on the production of the spectrum, seems conclusive in assigning these bands to the diatomic molecule MgH. The ultra-violet spectrum of magnesium hydride is not so well known. The band at λ 2430 and the series of double lines in the region λ 2940 to λ 3100, which were recorded by Prof. Fowler in 1909 as accompanying the group of bands in the visible region, appear to have undergone no further investigation. In view of the important part played by hydride band spectra in the correlation of molecular and atomic electronic energy levels, it was thought that a study of these features might prove of interest in yielding further information on the energy states of the MgH molecule. The present paper deals with observations on the band at λ 2430; details of an investigation of the other features of the ultra-violet spectrum will be given in a later communication.

Morphology Evolution and Luminescence Properties of YF3: Sm Nano-/Microcrystals

2012 ◽  
Vol 463-464 ◽  
pp. 112-118
Author(s):  
Feng Tao ◽  
Geng Zhu ◽  
Zhi Jun Wang ◽  
Feng Pan ◽  
Yu Feng Sun ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Growth Mechanism ◽  
Room Temperature ◽  
Red Light ◽  
Environmentally Friendly ◽  
Morphology Evolution ◽  
Flat Panel Display ◽  
Flat Panel ◽  
Display Devices ◽  
Potential Applications

Abstract. Recently, there has been increasting interest in the doping of nano-/microcrystal hosts with Sm3+. However, very few examples of Sm3+doped YF3-based nanophosphors have been reported. In this paper, a variety of uniform YF3:Sm nano-/microcrystals have been successfully prepared by a facile, effective, and environmentally friendly hydrothermal method. The morphology evolution process has been investigated by quenching the reaction at different time. Based on the results, a possible growth mechanism is presented in detail. The as-obtained YF3:Sm nano-/microcrystals show strong yellow and red light emissions under room temperature, which is quite different from those reported previously and might find potential applications in fields such as light phosphor powers and advanced flat panel display devices.

Effect of wet-chemical substrate smoothing on passivation of ultrathin-SiO2/n-Si(111) interfaces prepared with atomic oxygen at thermal impact energies

Open Physics ◽  
2011 ◽  
Vol 9 (6) ◽  
Author(s):  
Heike Angermann ◽  
Orman Gref ◽  
Bert Stegemann
Keyword(s):  
Atomic Oxygen ◽  
Silicon Oxide ◽  
Visible Region ◽  
Atomic Scale ◽  
Favourable Effect ◽  
Silicon Oxide Layer ◽  
Potential Applications ◽  
Wet Chemical ◽  
Pre Treatment ◽  
Impact Energies

AbstractUltrathin SiO2 layers for potential applications in nano-scale electronic and photovoltaic devises were prepared by exposure to thermalized atomic oxygen under UHV conditions. Wet-chemical substrate pretreatment, layer deposition and annealing processes were applied to improve the electronic Si/SiO2 interface properties. This favourable effect of optimized wet-chemical pre-treatment can be preserved during the subsequent oxidation. The corresponding atomic-scale analysis of the electronic interface states after substrate pre-treatment and the subsequent silicon oxide layer formation is performed by field-modulated surface photovoltage (SPV), atomic force microscopy (AFM) and spectroscopic ellipsometry in the ultraviolet and visible region (UV-VIS-SE).

scholarly journals Luminescence of Eu3+ in Some Scandium Phosphates

2021 ◽  
pp. 638-640
Author(s):  
Rajani A. Bhoyar ◽  
A. C. Nayak
Keyword(s):  
Solid State ◽  
Energy Levels ◽  
Concentration Quenching ◽  
Lanthanide Ions ◽  
Photoluminescence Properties ◽  
Trivalent Metal ◽  
Suitable Host ◽  
Relative Ease ◽  
Luminescence Efficiency ◽  
Light Lanthanides

Lanthanide ions are very efficient activators. Due to the presence of shielded 4f shell, the energy levels can be predicted with relative ease. Interaction with the surrounding lattice is minimum and luminescence efficiency is high. For this reason, many important phosphors having various applications have been discovered which use lanthanide activators. For obtaining efficient phosphors, it is important to find a suitable host for lanthanide activators which can accommodate these ions without concentration quenching. The hosts must be transparent to the emitted light. Lanthanides, most commonly occur as trivalent. Thus, hosts constituted by trivalent metals can be suitable. Yttrium compounds have been extensively studied as hosts. Scandium is another trivalent metal. Compared to the yttrium compounds, Scandium compounds have been very scarcely studied as hosts. We are investigating Scandium compounds as luminescence hosts. Synthesis and photoluminescence properties of Sr9 Sc (PO4)7 : Eu3+ and Sr8MgSc(PO4)7:Eu3+ phosphor are described in this work. The phosphors were prepared by solid state reaction. Usually, these phosphors are reduced and results on Eu2+ photoluminescence are reported. However, we have recorded photoluminescence before reduction and thus new results on Eu3+ emission could be obtained.

scholarly journals The Effect of Ionising Radiation on the Luminescence Properties of Fluoroperovskites

2021 ◽  
Author(s):  
◽  
Joseph Schuyt
Keyword(s):  
Energy Levels ◽  
Thermal Quenching ◽  
Ionising Radiation ◽  
Luminescence Properties ◽  
Readout System ◽  
Tissue Equivalent ◽  
Potential Applications ◽  
Radiation Induced ◽  
Medical Dosimetry ◽  
Physical Phenomena

<p>The luminescence of crystalline compounds can be used to monitor many physical phenomena, including doses of ionising radiation. Optically stimulated luminescence (OSL), thermoluminescence (TL), and radiophotoluminescence (RPL) have been successfully employed in dosimetry. However, few materials possess both the structural and luminescence properties required for medical dosimetry. This thesis aimed to investigate the luminescence features of the class of compounds known as fluoroperovskites. Emphasis was placed on studying the effects of irradiation on the luminescence properties, such that the compounds could be evaluated regarding potential applications in clinical dosimetry. Samples were primarily characterised using photoluminescence (PL), radioluminescence (RL), OSL, RPL, TL, and transmittance spectroscopy.  OSL was observed in the majority of samples due to the existence of electron trapping F-type centres. F-centre/Mn complexes were observed in all AMgF3:Mn compounds after irradiation and the energy levels of the complexes in each compound were experimentally determined. The most promising potential dosimeter host material was the near tissue-equivalent NaMgF3. When doped with Mn2+, the compound exhibited RPL via the formation of F-centre/Mn complexes and OSL via several trapping centres. The RPL could be probed independently to the OSL such that the compound could function as a hybrid OSL/RPL dosimeter. In the NaMgF3:Ln compounds, RPL occurred via the radiation-induced reduction Ln3+ → Ln2+ for Ln = Sm, Dy, and Yb. The reduction Sm3+ → Sm2+ was highly stable and could be non-destructively probed independently to the OSL. The Sm doped compound also exhibited radiation-induced conductivity that could be coupled with the RL, such that the compound could function as a real-time hybrid optical/electrical dosimeter. Charge kinetics, thermal quenching, and binding energy models were developed and applied to the compounds.   Finally, a two-dimensional readout system was designed and constructed. The capabilities of the system were evaluated using the OSL of NaMgF3:Eu and NaMgF3:Mn. Sensitivities to doses from < 10 mGy to > 1 Gy were obtained along with sub-millimetre spatial resolutions.</p>

scholarly journals Photoluminescence properties of ZrO2:Gd3+, ZrO2:Gd3+ – Dy3+ and ZrO2:Gd3+ – Yb3+ phosphors by Pechini method

2018 ◽  
Vol 36 (1) ◽  
pp. 157-161
Author(s):  
Esra Yildiz
Keyword(s):  
Powder Diffraction ◽  
Optical Materials ◽  
Pechini Method ◽  
Photoluminescence Properties ◽  
Emission Analysis ◽  
Lifetime Measurements ◽  
X Ray ◽  
Thermal Gravimetry ◽  
Potential Applications ◽  
Scanning Electron

AbstractZr0.99Gd0.01O2, Zr0.98Gd0.01Dy0.01O2 and Zr0.98Gd0.01Yb0.1O2 phosphors were synthesized by Pechini method at 1200 °C for 12 h in air. The phosphors were characterized by using X-ray powder diffraction (XRD), differential thermal analysis/thermal gravimetry (DTA/TG), scanning electron microscopy (SEM) and photoluminescence spectrofluorometer (PL). X-ray powder diffraction studies showed that the phosphors were crystallized as monoclinic and tetragonal multiphases. The particle size of the phosphors after heat treatment at 1200 °C was found to be of 200 nm to 250 nm. Luminescence studies on these phosphors have been carried out on the emission and excitation, along with lifetime measurements. The results of emission analysis indicate that the phosphors are expected to find potential applications as new optical materials.

scholarly journals Synthesis, Structure and Photoluminescence Properties of 2D Organic–Inorganic Hybrid Perovskites

2019 ◽  
Vol 9 (23) ◽  
pp. 5211 ◽  
Author(s):  
Liu ◽  
Li ◽  
Yao ◽  
He ◽  
Liu ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Laser Power ◽  
Radiation Detection ◽  
Photoluminescence Properties ◽  
Atom Number ◽  
Layer Spacing ◽  
Inorganic Hybrid ◽  
Potential Applications ◽  
Halide Perovskites ◽  
Organic Amines

Two-dimensional (2D) layered hybrid organic–inorganic perovskites have potential applications in solar cells, electroluminescent devices and radiation detection because of their unique optoelectronic properties. In this paper, four 2D layered hybrid organic–inorganic halide perovskites of (C6H5CH2NH3)2PbCl4, (C6H5CH2NH3)2PbBr4, (C6H5CH2NH3)2PbI4 and (C4H9NH3)2PbBr4 were synthesized by solvent evaporation. Their crystal structure and surface morphology were studied. The effects of different halogens and organic amines on perovskites’ absorption spectra were investigated, and the photoluminescence (PL) properties were studied by femtosecond ultrafast spectroscopy. The experimental results show that the four perovskites are well crystallized and oriented. With the increase of halogen atom number (Cl, Br, I) in turn, the UV-Vis absorption spectra peaks of perovskites redshift due to the increasing of the layer spacing, but organic amines have little effect on the spectra of perovskites. The PL intensity increases with increasing laser power, but the lifetime decreases with increasing laser power, which is mainly due to the non-geminate recombination. This research is of great significance for realizing the spectral regulation of organic–inorganic hybrid perovskites and promoting their application in nano-photonics and optoelectronic devices.

scholarly journals Tailoring Electro/Optical Properties of Transparent Boron-Doped Carbon Nanowalls Grown on Quartz

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 547 ◽  
Author(s):  
Mattia Pierpaoli ◽  
Mateusz Ficek ◽  
Michał Rycewicz ◽  
Mirosław Sawczak ◽  
Jakub Karczewski ◽  
...  
Keyword(s):  
Optical Properties ◽  
Growth Temperature ◽  
Structural Characteristics ◽  
Visible Region ◽  
Boron Doping ◽  
Light Transmittance ◽  
Boron Doped ◽  
Energy Conversion And Storage ◽  
Potential Applications ◽  
Carbon Nanowalls

Carbon nanowalls (CNWs) have attracted much attention for numerous applications in electrical devices because of their peculiar structural characteristics. However, it is possible to set synthesis parameters to vary the electrical and optical properties of such CNWs. In this paper, we demonstrate the direct growth of highly transparent boron-doped nanowalls (B-CNWs) on optical grade fused quartz. The effect of growth temperature and boron doping on the behavior of boron-doped carbon nanowalls grown on quartz was studied in particular. Temperature and boron inclusion doping level allow for direct tuning of CNW morphology. It is possible to operate with both parameters to obtain a transparent and conductive film; however, boron doping is a preferred factor to maintain the transparency in the visible region, while a higher growth temperature is more effective to improve conductance. Light transmittance and electrical conductivity are mainly influenced by growth temperature and then by boron doping. Tailoring B-CNWs has important implications for potential applications of such electrically conductive transparent electrodes designed for energy conversion and storage devices.

scholarly journals Ultrabroadband two-dimensional electronic spectroscopy reveals energy flow pathways in LHCII across the visible spectrum

2019 ◽  
Vol 205 ◽  
pp. 09034
Author(s):  
Minjung Son ◽  
Alberta Pinnola ◽  
Roberto Bassi ◽  
Gabriela S. Schlau-Cohen
Keyword(s):  
Energy Transfer ◽  
Excited States ◽  
Energy Flow ◽  
Energy Levels ◽  
Electronic Spectroscopy ◽  
Visible Region ◽  
Visible Spectrum ◽  
Energy Relaxation ◽  
Two Dimensional ◽  
Flow Pathways

We utilise ultrabroadband two-dimensional electronic spectroscopy to map out pathways of energy flow in LHCII across the entire visible region. In addition to the well-established, low-lying chlorophyll Qy bands, our results reveal additional pathways of energy relaxation on the higher-lying excited states involving the S2 energy levels of carotenoids, including ultrafast carotenoid-to-chlorophyll energy transfer on 90-150 fs timescales.

Sign in / Sign up

Export Citation Format

Share Document