scholarly journals Ag-Sensitized NIR-Emitting Yb3+-Doped Glass-Ceramics

2020 ◽  
Vol 10 (6) ◽  
pp. 2184
Author(s):  
Francesco Enrichi ◽  
Elti Cattaruzza ◽  
Tiziano Finotto ◽  
Pietro Riello ◽  
Giancarlo C. Righini ◽  
...  
Keyword(s):  
Near Infrared ◽  
Level Structure ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Salt Bath ◽  
Dip Coating ◽  
Optical Measurements ◽  
Excitation Spectra ◽  
Energy Level Structure ◽  
Pl Emission

The optical photoluminescent (PL) emission of Yb3+ ions in the near infrared (NIR) spectral region at about 950–1100 nm has many potential applications, from photovoltaics to lasers and visual devices. However, due to their simple energy-level structure, Yb3+ ions cannot directly absorb UV or visible light, putting serious limits on their use as light emitters. In this paper we describe a broadband and efficient strategy for sensitizing Yb3+ ions by Ag codoping, resulting in a strong 980 nm PL emission under UV and violet-blue light excitation. Yb-doped silica–zirconia–soda glass–ceramic films were synthesized by sol-gel and dip-coating, followed by annealing at 1000 °C. Ag was then introduced by ion-exchange in a molten salt bath for 1 h at 350 °C. Different post-exchange annealing temperatures for 1 h in air at 380 °C and 430 °C were compared to investigate the possibility of migration/aggregation of the metal ions. Studies of composition showed about 1–2 wt% Ag in the exchanged samples, not modified by annealing. Structural analysis reported the stabilization of cubic zirconia by Yb-doping. Optical measurements showed that, in particular for the highest annealing temperature of 430 °C, the potential improvement of the material’s quality, which would increase the PL emission, is less relevant than Ag-aggregation, which decreases the sensitizers number, resulting in a net reduction of the PL intensity. However, all the Ag-exchanged samples showed a broadband Yb3+ sensitization by energy transfer from Ag aggregates, clearly attested by a broad photoluminescence excitation spectra after Ag-exchange, paving the way for applications in various fields, such as solar cells and NIR-emitting devices.

Synthesis and Characterization of Y2O3:Eu3+ Film Derived by Sol-Gel Processing

2007 ◽  
Vol 336-338 ◽  
pp. 593-596
Author(s):  
Chun Yang ◽  
Jun Ying Zhang ◽  
Hai Bing Feng ◽  
Wei Chang Hao ◽  
Tian Min Wang
Keyword(s):  
Raw Materials ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Dip Coating ◽  
Organic Additive ◽  
Excitation Spectra ◽  
Excitation Peak ◽  
Close Relationship ◽  
Dip Coating Technique

Y2O3:Eu3+ thin film was synthesized by sol-gel method with inorganic salt raw materials, and the crystal structure and luminescent properties were investigated. By adding organic additive to the sol, a homogeneous film with high luminescent intensity could be obtained by dip-coating technique on the surface of alumina sheet and quartz glass. Structures of the films were studied by XRD and SEM. The excitation spectra of the films showed a wide excitation peak from 200nm to 260nm, and the emission spectra had a strongest emission peak at 611nm which revealed a close relationship with the calcining temperature.

scholarly journals Mode Sensitivity Exploration of Silica–Titania Waveguide for Refractive Index Sensing Applications

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7452
Author(s):  
Muhammad A. Butt ◽  
Andrzej Kaźmierczak ◽  
Cuma Tyszkiewicz ◽  
Paweł Karasiński ◽  
Ryszard Piramidowicz
Keyword(s):  
Refractive Index ◽  
High Performance ◽  
Near Infrared ◽  
Sol Gel ◽  
Cost Effective ◽  
Dip Coating ◽  
Infrared Wavelength ◽  
Refractive Index Sensing ◽  
Sensing Applications ◽  
Coating Method

In this paper, a novel and cost-effective photonic platform based on silica–titania material is discussed. The silica–titania thin films were grown utilizing the sol–gel dip-coating method and characterized with the help of the prism-insertion technique. Afterwards, the mode sensitivity analysis of the silica–titania ridge waveguide is investigated via the finite element method. Silica–titania waveguide systems are highly attractive due to their ease of development, low fabrication cost, low propagation losses and operation in both visible and near-infrared wavelength ranges. Finally, a ring resonator (RR) sensor device was modelled for refractive index sensing applications, offering a sensitivity of 230 nm/RIU, a figure of merit (FOM) of 418.2 RIU−1, and Q-factor of 2247.5 at the improved geometric parameters. We believe that the abovementioned integrated photonics platform is highly suitable for high-performance and economically reasonable optical sensing devices.

Preparation and Characterization of ZnO Thin Film Doped with Eu via Sol-Gel Method

2007 ◽  
Vol 336-338 ◽  
pp. 585-588 ◽  
Author(s):  
Dao Qi Xue ◽  
Jun Ying Zhang ◽  
Hai Bing Feng ◽  
Tian Min Wang
Keyword(s):  
Thin Film ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Dip Coating ◽  
Luminescence Spectra ◽  
Zno Thin Film ◽  
Excitation Spectra ◽  
Coating Method ◽  
Dip Coating Method

ZnO:Eu3+ films were obtained by dip-coating method and influence of heat treatment on luminescent properties was investigated. Emission and excitation spectra revealed that the organic and nitrate molecules, which adhered on the surface of films when the samples were treated at lower temperatures (300oC-400oC), played an important role on the luminescent properties. At higher temperatures (500oC-800oC), the luminescence spectra of ZnO and Eu3+ were quite different with those treated at lower temperatures. Energy transferred from ZnO host to Eu3+ was obviously observed in the emission and excitation spectra. The luminescence mechanism was discussed briefly.

Measurement and Characterization of CeO2-TiO2 Ion Storage Films for Electrochromic Devices

2017 ◽  
Vol 726 ◽  
pp. 276-281
Author(s):  
Wei Shan Wu ◽  
Xiao Ping Liang ◽  
Jun Wang ◽  
Peng Chen ◽  
Wei Zhang ◽  
...  
Keyword(s):  
Sol Gel ◽  
Dip Coating ◽  
Optical Measurements ◽  
Molar Ratio ◽  
Nitrate Hexahydrate ◽  
Electrochromic Devices ◽  
Molar Ratios ◽  
Ion Storage ◽  
The Stability ◽  
Dip Coating Technique

CeO2-TiO2 sols and films were prepared by sol-gel method. The precursor sols consist of a mixture of cerium nitrate hexahydrate Ce(NO3)3·6H2O, butyl titanate Ti(OC4H9)4 and anhydrous ethanol CH3CH2OH. The films were deposited using the dip-coating technique and calcined at 310 °C in an oxygen atmosphere. The effects of the molar ratios of cerium to titanium（0.55:1, 0.70:1, 0.85:1, 1:1）on the microstructure and properties of (CeO2)x-TiO2 films were investigated. The surface morphology, electrochemical performance and optical property were characterized by FE-SEM, cyclic voltammetry (CV) and UV-Visible spectrometer, respectively. The results show that the properties of the films are tightly related to cerium to titanium ratio. When the molar ratio of cerium to titaniumis 0.85:1, the ion storage capacity value of CeO2-TiO2 film is 19.99mC/cm2, whereas the pure TiO2 film is 11.52mC/cm2. The stability tests and optical measurements confirm that the developed CeO2-TiO2 films can be use as ion storage-counter eletrodes in electrochromic devices.

Effect of Withdrawal Speed on the Structural, Optical and Morphological Properties of NiO Thin Films Obtained by Sol-Gel Dip Coating Method

2017 ◽  
Vol 31 ◽  
pp. 29-35 ◽  
Author(s):  
Abdelouahab Noua ◽  
Rebai Guemini ◽  
Hichem Farh ◽  
Mourad Zaabat
Keyword(s):  
Thin Films ◽  
Near Infrared ◽  
Sol Gel ◽  
Optical Transmittance ◽  
Dip Coating ◽  
Morphological Properties ◽  
Speed Increase ◽  
Withdrawal Speed ◽  
Coating Method ◽  
Dip Coating Method

In this study, pure nickel oxide thin films were prepared by a sol-gel dip coating method with different withdrawal speeds, onto glass substrates and their structural, optical and morphological properties were investigated. The structural properties of NiO films were characterized by X-ray diffraction (XRD), Polycrystalline structures of the prepared films were detected. The optical properties of the films were studied by UV–visible spectrophotometer and the optical transmittance of the films within the visible and near infrared region was found to be more than 75% and decrease when the withdrawal speed increase. The surface morphology of the films was observed by atomic force microscopy and it was found that the root mean square (RMS) roughness increases from 3.78 to 15 nm when the withdrawal speed increased from 30 to70 mm/min. Thus, the withdrawal speed is a key factor to change the NiO thin films properties.

scholarly journals Rare Earth FreeZn3V2O8Phosphor with Controlled Microstructure and Its Photocatalytic Activity

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hom Nath Luitel ◽  
Rumi Chand ◽  
Toshio Torikai ◽  
Mitsunori Yada ◽  
Takanori Watari
Keyword(s):  
Photocatalytic Activity ◽  
Rare Earth ◽  
Quantum Yield ◽  
Sol Gel ◽  
Emission Spectra ◽  
Host Lattice ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
Visible Absorption ◽  
Pl Emission

Microsphere of rare earth free phosphor,Zn3V2O8, with broadband yellowish white emission was synthesized by combustion route and compared with the hydrothermal, sol-gel, and solid state reaction methods. The phosphor samples were characterized by X-ray diffraction and scanning electron microscopy. UV-visible absorption and photoluminescence (PL) emission and excitation spectra were investigated for these phosphors.Zn3V2O8phosphor containing 10 mol% of H3BO3flux exhibited enhanced PL emission showing broadband from 450 nm to 750 nm. Effect of stoichiometry of Zn and V on the host lattice and its effect on the PL emission spectra were studied. Series of Mg3V2O8,Ca3V2O8, and Sr3V2O8phosphors were also synthesized and compared to theZn3V2O8phosphor in terms of PL emission and internal quantum yield, and it was found thatZn3V2O8is the most efficient phosphor among the other phosphors studied with quantum yield of 60%. The visible light irradiated photocatalytic activity of these phosphors was investigated and it was found that the hydrothermalZn3V2O8exhibited enhanced activity.

scholarly journals Low-Temperature Synthesis of Vanadium Dioxide Thin Films by Sol-Gel Dip Coating Method

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Ladawan Chotirat ◽  
Sutham Niyomwas ◽  
Witthawat Wongpisan ◽  
Sitthisuntorn Supothina
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Vanadium Dioxide ◽  
Near Infrared ◽  
Sol Gel ◽  
Optical Transmittance ◽  
Dip Coating ◽  
Tube Furnace ◽  
Vacuum Tube ◽  
Synthesis Conditions

The vanadium dioxide (VO2) thin films were synthesized by sol-gel dipping on a glass slide substrate at low temperature of 500°C in a vacuum tube furnace at a pressure of 2 × 10−3 mbar by 2-step calcination without an intermediate gas purging. Synthesis conditions, including temperature, vacuum pressure, and calcination steps in the vacuum tube furnace, were investigated to find the optimum condition that promoted the formation of VO2 phase. It was found that the 2nd calcination step was very important in realizing the monoclinic vanadium dioxide (VO2 (M)). The results of the valence electron analysis revealed the outstanding phase of VO2 and a small amount of V2O5 and V2O3 phases. The small crystallites of the VO2 were homogeneously distributed on the surface, and the grain was of an irregular shape of ∼220−380 nm in size. The film’s thickness was in a range of 69−74 nm. The film exhibited a metal-to-insulator transformation temperature of ∼68oC and good thermochromic property. Visible optical transmittance remained at ∼40−50% when the sample’s temperature changed from 25 to 80°C for a near infrared (NIR) region.

EFFECT OF ANNEALING TEMPERATURE ON OPTICAL PROPERTIES OF TITANIUM DIOXIDE THIN FILMS PREPARED BY SOL-GEL METHOD

2011 ◽  
Vol 25 (31) ◽  
pp. 4163-4166 ◽  
Author(s):  
M. T. SARODE ◽  
P. N. SHELKE ◽  
Y. B. KHOLLAM ◽  
S. R. JADKAR ◽  
B. B. KALE ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Annealing Temperature ◽  
Anatase Phase ◽  
Sol Gel ◽  
Nanocrystalline Structure ◽  
Dip Coating ◽  
Optical Measurements ◽  
Crystallite Sizes

TiO 2 sol-gel thin films were deposited on glass substrates by dip coating method. Nanocrystalline TiO 2 thin films were prepared at 300°C. The effect of annealing temperature on optical properties of nanocrystalline TiO 2 thin films was studied. The films were characterized by different techniques: XRD, UV-visible spectroscopy, FTIR spectroscopy and FESEM. The characterization studies revealed that the films are crystallized as anatase phase and are nano-structured. The optical measurements were showed the indirect band gap between 3.31 and 3.35 eV with corresponding crystallite sizes between 8.9 and 3.7 nm at the temperatures 300, 400 and 500°C. The FESEM images of film were showed spherical nanocrystalline structure of TiO 2 particles with the crystallite sizes between 30 and 100 nm. It is also observed that refractive index of the film increases with increasing the annealing temperature. The smaller crystallite size gives larger band gap due to quantum size effects.

Study on the Cracking of SiO2-TiO2 Films Prepared by Sol-Gel Method

2005 ◽  
Vol 475-479 ◽  
pp. 1227-1230 ◽  
Author(s):  
Feng Zhou ◽  
Kai Ming Liang ◽  
Hua Shao
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
Glass Ceramics ◽  
Dip Coating ◽  
Tetraethyl Orthosilicate ◽  
Heating Process ◽  
Tio2 Films ◽  
Cracking Behavior ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

In this paper, the cracking behavior of sol-gel-derived SiO2-TiO2 films on glass-ceramics substrates is characterized by means of DTA, XRD and SEM. The SiO2-TiO2 films are deposited by sol-gel dip coating with tetrabutyl orthotitanate (Ti(OBu)4) and tetraethyl orthosilicate (TEOS) as raw precursors. The result shows that the cracking of the films is mainly related to the surface cleanliness of the substrate, the thermal expansion coefficients of the film and the substrate, the viscosity of the mixed sol, and the unbalanced stress produced during drying and heating process. The films without cracks were obtained by modifying the composition of sol and controlling the relative humidity and the heating rate of heat treatment.

Glass-Based Photonic Crystals: From Fabrication to Applications

2014 ◽  
Vol 90 ◽  
pp. 121-126
Author(s):  
Andrea Chiappini ◽  
A. Chiasera ◽  
Cristina Armellini ◽  
Alessandro Carpentiero ◽  
Anna Lukowiak ◽  
...  
Keyword(s):  
Photonic Crystals ◽  
Near Infrared ◽  
Colloidal Crystal ◽  
Sol Gel ◽  
Stop Band ◽  
Rf Sputtering ◽  
Optical Measurements ◽  
Cavity Resonance ◽  
Sensitive Material ◽  
Chemical Route

We report on the fabrication and on the assessment of the properties of two glass-based photonic crystals (PhCs) obtained using alternative approaches such as rf-sputtering and sol-gel techniques. (i) By means of rf-sputtering a one-dimensional dielectric photonic crystal constituted by an Er3+-doped SiO2 active layer inserted between two Bragg reflectors consisting of 10 pairs of SiO2∕TiO2 layers has been realized. Near infrared transmittance spectra evidenced the presence of a stop band from 1500 to 2000 nm with a cavity resonance centered at 1749 nm. Intensity enhancement and narrowing of the emission band of Er3+ ions, due to the cavity effect have been observed and a cavity quality factor of 890 has been achieved. (ii) Through chemical route a 3D colloidal crystal based on polystyrene (PS) nanoparticles (NPs) embedded in elastomeric matrix has been realized. In the specific has been shown that the structure can produce a variation of its color applying different organic solvents that can be also easily observed by the naked eye. Optical measurements have evidenced a red shift of the diffraction peak as a function of the solvents applied. This feature has been exploited in order to create a sensitive material showing high sensitivity and reversibility of the signal change.

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