Doping Concentration Of Yb3 Research Articles

NaYF4:Yb3+/Ho3+ up-conversion luminescence and its low temperature sensing characteristics

Pure hexagonal [Formula: see text]-NaYF4 micron crystals were synthesized by the hydrothermal method with the up-conversion luminescence properties studied by doping Yb[Formula: see text]/Ho[Formula: see text]. The up-conversion fluorescence spectra and fluorescence lifetime of [Formula: see text]-NaYF4 micron crystals were determined by FLS-980 transient fluorescence spectrometer. By changing the doping concentration of Yb[Formula: see text]/Ho[Formula: see text], the optimal doping concentration was confirmed to be 20%Yb[Formula: see text]/2%Ho[Formula: see text]. The fluorescence spectrum was obtained by changing pump power, the relationship between power and intensity was analyzed, and the [Formula: see text]-NaYF4 micron crystal green and red emission up-conversion process was obtained into a two-photon process. The 5F[Formula: see text]I8 and 5S[Formula: see text]I8 of the sample were thermally coupled to obtain a large absolute sensitivity (Sa) of low temperature. The maximum absolute sensitivity within the range of 64–194[Formula: see text]K is 0.0097[Formula: see text]K[Formula: see text] at 144[Formula: see text]K, while maximum absolute sensitivity at 333[Formula: see text]K is 0.00335[Formula: see text]K[Formula: see text] in the range of 293–493[Formula: see text]K. The experimental results show that the sensing characteristics of [Formula: see text]-NaYF4:Yb[Formula: see text]/Ho[Formula: see text] at low temperature are better than those at high temperature, and it has the potential to be used in the field of temperature sensing.

Prolonging blue TADF-OLED lifetime through ytterbium doping of electron transport layer

Balanced charge carrier transport and broad carrier recombination zone are essential features for reducing triplet exciton concentration and suppressing triplet-mediated annihilation processes, which affect the performance and stability of blue-emitting organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) phenomenon. Doping of organic layers is among the most effective methods to control these features. Herein, the impact of ytterbium (Yb) doping of electron transport layer on the TADF-OLED performance, and particularly the lifetime, was thoroughly assessed. It was found that the lower doping concentrations of Yb (<10wt%) cause electron trapping and reduced current density, whereas higher Yb concentrations facilitate electron transport in the device. Although the introduction of Yb somewhat deteriorated device efficiency, it extended operational lifetime of blue-emitting device by 2 orders of magnitude (up to 46 hours at 1000 cd/m2). This was shown to occur as a result of Yb-assisted non-radiative triplet exciton quenching at the electron transport and emission layer interface, thus diminishing detrimental exciton annihilation processes.

Solution-Processed High Performance Ytterbium-Doped In2O3 Thin Film Transistor and Its Application in Common-Source Amplifier

In this article, we investigated Ytterbium (Yb)-doped Indium-oxide (In2O3)-based thin-film transistor (TFT) prepared by the solution-processed. Indium-Yb-oxide (InYbO) films with different Yb-doping concentrations were prepared by the solution-processed to reveal the variation of physical properties of In2O3 films with the changing of Yb-doping concentration. The results show that Yb-doping can improve the microstructure and surface roughness of In2O3 films and suppress the oxygen vacancy defects. When the Yb-doping concentration reaches 1 mol%, the InYbO-TFT exhibits optimal electrical performance. In addition, the performance of InYbO-TFT under positive bias stability (PBS) test is also significantly improved. The device with 1 mol% Yb concentration shows a voltage shift of 1.27 V after 3600 s of +20 V bias test, which is about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\times $ </tex-math></inline-formula> stable than the In2O3-TFT. Eventually, based on this InYbO-TFT, a common-source amplifier was designed. This amplifier has a 16.03 dB Gain and a cut-off frequency of 470 Hz with excellent response speed, which shows great application potential.

Pure and Yb-Doped LaxYySc4-x-y(BO3)4 Crystals: A Review of Recent Advances

This paper reviews the progress in developing the LaxYySc4-x-y(BO3)4-LYSB and Yb-doped LaxYySc4-x-y(BO3)4-LYSB:Yb huntite-type crystals grown by the Czochralski method as new candidates for the next generation of nonlinear optical (NLO) and/or laser crystals. Considering the incongruent melting of these crystals, the initial compositions of the melt and the pulling and rotation rates were optimized. Additionally, a special thermal setup was engineered to grow LYSB-type crystals by the Czochralski crystal growth method. The chemical compositions of the LYSB and LYSB:Yb grown crystals were found to be La0.78Y0.32Sc2.90(BO3)4 and La0.78Y0.32Yb0.04Sc2.86(BO3)4, respectively. Therefore, for the LYSB:Yb crystal, the doping concentration of Yb3+ ions was considered to be 4 at.% with respect to the nonstoichiometric (La1-xYx)1.25Sc2.75(BO3)4 undoped compounds, i.e., LYSB:Yb (4 at.%). In terms of NLO properties, the obtained results demonstrate that LYSB and LYSB:Yb (4 at.%) crystals possess remarkable properties specific to huntite-type crystals. The main advantage of these crystals consists in the fact that they may be obtained with large dimensions and excellent optical quality by the Czochralski method, which recommends them as a new class of highly efficient crystals for different NLO applications, including second harmonic generation (SHG) of high-power or high-energy laser beams. The laser performances of the LYSB:Yb (4 at.%) crystal prove its favorable intrinsic properties to generate laser emissions in the 1 µm range with high efficiency. The efficient laser emission at ~1028 nm together with good NLO characteristics to convert its own emission into emission at ~514 nm via SHG make the LYSB:Yb (4 at.%) crystal a very promising active medium to be used in self-frequency doubling configuration.

Controllable structural and optical properties of NaYF4:Tm, Yb microparticles by Yb3+ doping for anti-counterfeiting.

Hexagonal NaYF4:Tm, Yb upconversion (UC) phosphors with excellent UC luminescence quantum efficiency and chemical stability meet demands for applications in bioimaging and anti-counterfeiting printing. In this work, a series of NaYF4:Tm, Yb upconversion microparticles (UCMPs) with different concentrations of Yb were synthesized by a hydrothermal method. Then, the UCMPs become hydrophilic through surface oxidation of the oleic acid (C-18) ligand to azelaic acid (C-9) using the Lemieux-von Rodloff reagent. The structure and morphology of UCMPs were investigated by X-ray diffraction and scanning electron microscopy. The optical properties were studied using diffusion reflectance spectroscopy and photoluminescent spectroscopy under 980 nm laser irradiation. The emission peaks of the Tm3+ ions are 450, 474, 650, 690, and 800 nm, attributed to the transitions from the excited state to ground state 3H6. These emissions are the results of two or three photon absorption through multi-step resonance energy transfer from excited Yb3+, confirmed via a power-dependent luminescence study. The results show that the crystal phases and luminescence properties of the NaYF4:Tm, Yb UCMPs are controlled by changing the Yb doping concentration. The printed patterns are readable under the excitation of a 980 nm LED. Moreover, the zeta potential analysis shows that the UCMPs after surface oxidation are water dispersible. In particular, the naked eye can observe the enormous upconversion emissions in UCMPs. These findings indicated that this fluorescent material is an ideal candidate for anti-counterfeiting and biological applications.

Effect of Yb[formula omitted] concentration on Er[formula omitted] doped CaF[formula omitted] single crystal for temperature sensor applications

Yb–Er co-doped CaF2 crystals with different Yb3+ ions concentrations are successfully grown by the temperature gradient technique (TGT) method. Up-conversion (UC) luminescence characteristics and optical temperature sensing behavior of all samples are thoroughly investigated in this work. Under the excitation of a 980 nm laser-diode, the up-conversion luminescence intensity firstly increases and then decreases. By adjusting the content of Yb3+ ions, multi-color visible light emissions of red, yellow and green could be easily obtained. The fluorescence intensity ratio from two thermally coupled 2H11/2 and 4S3/2 levels technology is used to evaluate the temperature sensing performance of Yb–Er co-doped CaF2 crystals. The concentration of Yb3+ ions shows a significant influence on the temperature sensing performance. The sensitivity reaches the maximum value of 2.24 × 10−3 K−1 at 548 K with a 5 at.% doping concentration of Yb3+ ions. The experiment also confirms that Yb–Er co-doped CaF2 crystal exhibit high stability as optical temperature sensors. In general, it is proved that Yb–Er​ co-doped CaF2 single crystals are a kind of promising materials used in the optical temperature sensor.

Fabrication of yttrium aluminosilicate fibers with high Yb3+ doping from Yb:YAG ceramic nanopowders and its application in single-frequency fiber lasers

A yttrium aluminosilicate fiber with a Yb doping concentration of 4.53 wt.% was fabricated by powder-in-tube method, in which the preform core was Yb:YAG ceramic nanopowders synthesized by co-precipitation method. Compared with the method of using YAG crystal rod as fiber core, the fiber composition design can be more flexible and a series of crystal rod processing technology can be circumvented. The absorption coefficient of the Yb-doped YAS fibers was measured 28.4 dB/cm at 976 nm. A single-frequency fiber laser was constructed with the YAS fiber length of 1cm. To our knowledge, this is the first time that rare earth (RE) doped YAS fiber prepared by powder-in-tube method was used in fiber laser.

Spectroscopic investigation of upconversion and downshifting properties LaF3:Tb3+,Yb3+: A dual mode green emitter nanophosphor

The optimization of dopant concentration in upconverting nanophosphor is a real problem because of distinct limits defined by surface quenching, energy transfer and cross relaxation phenomenon. In this work, LaF3 based nanophosphors with different doping concentration of Yb3+ and Tb3+ ions were prepared by coprecipitation route. Particles are formed in spherical shape with narrow size distribution i.e. in ∼50–80 nm range. The volume of LaF3 unit cell shrinks with the doping of Tb3+ and Yb3+, whereas no variation in its phase were observed. The nanophosphors exhibit characteristics of dual mode spectral emitter. Thus, irrespective of excitation source (i.e. either UV or NIR), the intense green emission at 541 nm was observed. The material LaF3 with optimized molar doping concentration of 5%Tb3+ and 10%Yb3+ shows intense green emission on excitation with either UV or IR light. The time resolve luminescence emission were studied to explore the probability of involved energy transfer process between two dopant ions.

Flame-made Y2O3:Yb3+/Er3+ upconversion nanoparticles: Mass production synthesis, multicolor tuning and thermal sensing studies

Developing a rapid and continuous synthesis method for scalable production of upconversion nanoparticles (UCNPs) plays an important role in the applications of advanced color display, high-resolution biomedical imaging and precise optical thermometry. Here, for the first time, we report the multicolor tunable upconversion luminescence (UCL) in Y2O3:Yb3+/Er3+ (x/1 mol%) UCNPs with the average size of ∼14 nm, which were successfully fabricated by liquid-fed flame aerosol synthesis with a high production rate of ∼40 g h−1. Under the excitation of 980 nm continuous-wave (CW) laser, the UCL color can be efficiently modulated from green to red and the red-to-green (R/G) UCL intensity ratio is enhanced dramatically as the doping concentration of Yb3+ ions increases from 1 to 15 mol%. The UCL color manipulation can be ascribed to the cross-relaxation (CR) and the energy back transfer (EBT) processes between Yb3+ and Er3+ ions, and it was proved by investigating the dependence of UCL on the pump power and the decay lifetimes of 4S3/2 and 4F9/2 states. Moreover, the coefficients of CR and EBT processes were also calculated by a rate equation model, and the results suggest that they are efficient in Y2O3 host. In addition, the optical thermal sensing performance was also evaluated by analyzing fluorescence intensity ratio (FIR) of the thermally coupled levels (2H11/2, 4S3/2) of Er3+ ions in Y2O3:Yb3+/Er3+ (1/1 mol%) UCNPs, achieving an excellent thermal sensitivity of 0.0196 K−1 at 543 K.

Controlled synthesis and upconversion luminescence properties of Yb3+/Er3+ co-doped Bi2O3 nanospheres for optical and X-ray computed tomography imaging

Bi2O3 nanospheres co-doped with Yb3+/Er3+ upconverting ions pair have been successfully synthesized via a facile hydrothermal method followed by a heat treatment. The resulting Bi2O3:Yb3+,Er3+ nanospheres show a monodisperse spherical morphology with narrow size distribution (~180 nm) and display intense upconversion luminescence under 980 nm laser excitation. It is found that the crystal structure, morphology and upconversion luminescence properties of nanospheres have a direct relationship with the doping concentration of Yb3+ and the subsequent calcination temperature. These Bi2O3:Yb3+,Er3+ nanospheres can be prepared in large quantities and can be easily modified with a layer of biocompatible polyethyleneimine (PEI) molecules. The yielded nanospheres could not only maintain uniform size and morphological characteristics, but also show good water dispersibility and biocompatibility. Remarkably, these Bi2O3:Yb3+,Er3+ upconversion nanophosphors could also act as an effective contrast agent for X-ray computed tomography (CT) imaging, which show higher contrast efficacy than commercial iodine-based contrast agent. The proposed facile synthetic route and inexpensive matrix materials pave the way for broad use of these Bi2O3:Yb3+,Er3+ nanospheres as ideal dual-mode bioimaging probes in biomedical field.

Fabrication of Yb:Lu2O3 Transparent Ceramics by Hot Isostatic Pressing: the Effect of Yb Doping Concentrations

Highly transparent ytterbium doped lutctium oxide (Yb:Lu2O3) transparent ceramics with different Yb doping concentrations (0.5–10 at% Yb) were fabricated from commercial powders by vacuum sintering combined with hot isostatic pressing (HIP) method. The effects of Yb3+ doping concentrations on the microstructure, optical performance and the thermal conductivity of Yb:Lu2O3 transparent ceramics were investigated. The grain size of Yb:Lu2O3 ceramics first decreased with Yb doping concentration increasing and then kept nearly unchanged at high Yb doping concentrations. Under 1750°C HIP sintering for 2h, The in-line transmittance of the 5 at.% Yb:Lu2O3 ceramics (3 mm thick) exceeds 81.52% at 1100 nm. And it had the average grain size about 2μm. As the doping concentrations increase, the overall thermal conductivity decreases slightly. The fluorescence emission spectrum implied high possibility of realizing laser output at 1080 nm by pumping at 980 nm.

Yb- and Mn-Doped Lead-Free Double Perovskite Cs2AgBiX6 (X = Cl-, Br-) Nanocrystals.

Lead-free double perovskite nanocrystals (NCs) have emerged as a new category of materials that hold the potential for overcoming the instability and toxicity issues of lead-based counterparts. Doping chemistry represents a unique avenue toward tuning and optimizing the intrinsic optical and electronic properties of semiconductor materials. In this study, we report the first example of doping Yb3+ ions into lead-free double perovskite Cs2AgBiX6 (X = Cl-, Br-) NCs via a hot injection method. The doping of Yb3+ endows the double perovskite NCs with a newly emerged near-infrared emission band (sensitized from the NC hosts) in addition to their intrinsic trap-related visible photoluminescence. By controlling the Yb-doping concentration, the dual emission profiles and photon relaxation dynamics of the double perovskite NCs can be systematically tuned. Furthermore, we have successfully inserted divalent Mn2+ ions in Cs2AgBiCl6 NCs and observed emergence of dopant emission. Our work illustrates an effective and facile route toward modifying and optimizing optical properties of double perovskite Cs2AgBiX6 (X = Cl-, Br-) NCs with an indirect bandgap nature, which can broaden a range of their potential applications in optoelectronic devices.

Defect analysis of TiO2 doped with ytterbium and nitrogen by ab initio calculations

Different defects are studied in the network of anatase TiO2 to improve the utilization of the material for photoelectrochemical applications. With the ab initio calculations, defect-induced TiO2 models with different doping concentrations and oxidation states of Yb and N dopants are studied. Oxygen-deficient systems are modeled, and the interaction of oxygen vacancy with the Yb and N dopant in the bulk of TiO2 is elucidated. Yb 4f states are coupled with the O 2p states reducing the band gap and shifting the absorption edge of the TiO2 toward visible regime. Increasing Yb doping concentration reduced the band gap, and the 2.08% Yb doping concentration is considered as an optimal Yb doping. Comparing the band structures of mono-doped and codoped samples, Yb, N codoping reduced the band gap while creating isolated states in the forbidden region. Compensated and non-compensated systems of Yb- and/or N-doped TiO2 models are studied. Charge compensation in Yb, N-codoped TiO2 stabilized the system, reduced the band gap without having isolated states and provided broader absorption band. The Ti16−xYbxNyO31−y, x = 2, y = 1, model provided minimum structure modification with the suitable band structure for photoelectrochemical applications explaining the experimental results for the synergistic effect of Yb, N codoping in TiO2.

Highly efficient infrared to visible up-conversion emission tuning from red to white in Eu/Yb co-doped NaYF4 phosphor.

Eu/Yb co-doped NaYF4 phosphors have been synthesized by the combustion method. The Eu doping was fixed and the effect of Yb doping concentration on the structural, morphological and luminescence properties has been investigated. X-ray diffraction analysis revealed that the phosphors consisted of mixed α- and β-phases, but the β-phase was dominant. All elements of the host and dopants, as well as adventitious C, were detected using X-ray photoelectron spectroscopy. The surface morphology showed a microrod-like structure with sharp hexagonal edges. Energy dispersive X-ray spectroscopy spectra proved the formation of the desired materials. The photoluminescence spectra illustrated the optical emission properties of Eu3+ in the red region when excited at 394 nm, while, under the same excitation, Yb3+ ions gave emission at 980 nm. The up-conversion (UC) emission of Eu/Yb co-doped NaYF4 produced a white color at the higher concentration of Yb excited by a 980 nm laser, which was made possible by green emission of Er contamination (from Yb source) and blue emission of Eu2+ ions. The lifetime of the Eu3+ UC luminescence at 615 nm was also affected by the Yb doping concentration. The temperature sensitivity associated with the Er3+ peaks at 520 and 542 nm was assessed as a function of temperature and the maximum of 0.0040 K-1 occurred at 463 K.

Highly Uniform Hollow GdF3 Ellipsoids: Controllable Synthesis, Characterization and Up-Conversion Luminescence Properties.

In this paper, the hollow GdF3 ellipsoids were successfully synthesized through a facile hydrothermal approach. The results indicated that the as-obtained GdF3 sample has an orthorhombic structure and the average length and diameter of the hollow ellipsoids are 750 nm and 350 nm, respectively. The possible formation mechanism of the hollow GdF3 ellipsoids has been presented. The upconversion (UC) luminescence properties of the hollow GdF3: Yb3+/Ln3+ (Ln3+ = Er3+, Tm3+, Ho3+) ellipsoids were systematically investigated, which showed green (Er3+, 4S3/2, 2H11/2 → 4I15/2), blue (Tm3+, 1G4 → 3H6), and green (Ho3+, 5S2 → 5I8) luminescence under 980 nm NIR excitation, respectively. Furthermore, the UC white light was successfully obtained in the GdF3: Yb3+/Er3+/Tm3+ sample through adjusting relative doping concentration of Yb3+, Er3+ and Tm3+ ions. These findings may reveal potential applications in the fields of laser, bioanalysis, optoelectronic and nanoscale devices due to multicolor emissions in the visible region.

Effect of Yb co-doping on the spectral properties of Er:YVO4 single crystal: A Judd Ofelt analysis

Single crystals of 0.7 at% Er:YVO4 co-doped with varied concentrations of Yb (1.5, 3.0 and 8.0 at%) were grown by optical floating zone technique. The absorption spectra of the grown crystal are characterized by the prominent absorption at 985 nm due to Yb ion and multiple absorption due to Er ions. The overall characteristic absorption for π-polarization (E||c) is stronger than that for σ-polarization (E┴c) due to alignment of dipole moments along c-direction. The line strength of all the transitions of Er ions decreases as the doping concentration of Yb increases. Judd Ofelt parameter Ω2, which strongly depends on the environment of ligand, decreases with increasing Yb concentration in the lattice. The value of spectroscopic quality factor was found to be nearly invariant (~ 1.80) with respect to the Yb doping concentration but better than that for Er doped YVO4 (~1.31) [1]. The radiative lifetime and emission cross-section of 4I13/2→4I15/2 transition of Er ions was also found to be independent of Yb doping concentration. This is one of the biggest advantages of Yb co-dopant as a good sensitizer in the Er:YVO4 as it results in high population density in upper level of Er ions making it. The emission cross-section of 4I13/2→4I15/2 line for excitation at 985 nm is ~ 2.33 × 10−20 cm2. Further, the values of emission cross-section for both the excitation at 808 nm (Er absorption line) and 985 nm (Yb absorption line) were found nearly same.

Regulation of sensitivity of Yb concentration to power-dependent upconversion luminescence colors

Controlling the power density of exciting light is a widely applied technological approach to dynamically tuning emission spectra to yield desirable luminescence properties, which is essential for various applications in laser devices, cancer cell imaging, biomarker molecule detections, thermometers and optoelectronic devices. However, most of upconversion systems are insensitive to power regulation. In this study, a series of Yb/Ho doped NaYF4 microrods with different Yb concentrations was synthesized by using a sodium citrate-assisted hydrothermal method. The dependence of upconversion characteristics of NaYF4:Yb/Ho microrods on Yb concentration and excitation power density are investigated in detail by a laser confocal microscopy system. The emission spectra exhibit discrete upconversion emission characteristic peaks that can easily be assigned to 5F3→5I8 (at about 488 nm), 5F4, 5S2→5I8 (at about 543 nm), 3K7, 5G4→5I8 (at about 580 nm) and 5F5→5I8 (at about 648 nm) transitions of Ho, respectively. The upconversion spectra and synchronous luminescence imaging patterns show that the luminescence ratio of red to green is not only dependent on the Yb concentration, but also sensitive to the excitation power. With Yb concentration increasing from 5% to 60%, the sensitivity of the power-controlled red to green luminescence ratio largely increases from 0.1% to 13.0%, corresponding to a clear luminescent color modification from green to red. These results indicate that the power-tuned red-to-green-luminescence ratio can be used as a method of measuring and evaluating Yb doping concentration. We attribute the sensitivity tuned by Yb concentration to the differences in population approach and upconversion mechanism for the red and green luminescence. By recording the slope of luminescence intensity versus exciting power density in a double-logarithmic presentation, we detect a small slope for the green emission relative to that for the red emission, especially at a high Yb concentration. These results indicate that the red upconversion process may be a three-photon process. The exciting power induced color adjusting is therefore explained by preferential three-photon population of the red emission due to the high 5S2→5G4 excitation rate, which is verified by down-conversions of emission spectra. Our present study provides a theoretical basis for the spectral tailoring of rare-earth micro/nano materials and supplies a foundation for the applications in rare-earth materials.

Effect of Yb doping concentration on crystallization kinetics in yttrium aluminum garnet nano-powders

Different ytterbium concentration–doped yttrium aluminum garnet (Yb:YAG) nanopowders were synthesized using coprecipitation with nitrate salts as the starting materials. The phase evolutions, morphologies, and microstructures of the powders synthesized from various ytterbium-doped precursors were investigated. Ytterbium doping concentration was discovered to have a crucial effect during the YAG phase formation from the precursor. Crystallized Yb:YAG powders were directly obtained at temperatures as low as 900°C without the formation of any intermediate phase. The crystallization kinetics of the Yb:YAG precursors were analyzed using non-isothermal differential scanning calorimetry. Avarami parameters of 0.97, 1.00, 1.13, and 1.21 were obtained for Yb doping concentrations of 0, 3, 6, and 9at% respectively, and crystallization activation energies of 1506±40, 1342±36, 1171±31, and 978.1±26kJ/mol were calculated. The activation energy for YAG crystallization was lower when a high Yb doping concentration was used because the presence of Yb3+ prohibited the presence of anionic SO42− in the precursors, thus enhancing the elemental diffusion between particles. Both the average grain size and particle size of Yb: YAG decreased when Yb doping concentration was increased, and at various calcination temperatures.

Effect of Yb doping on the refractive index and thermo-optic coefficient of YVO4 single crystals.

Single crystals of YVO4 with different doping concentrations of Yb (1.5, 3.0, 8.0, and 15.0 at. %) and with good crystalline quality (FWHM ∼43-55 arc sec of rocking curve) were grown by the optical floating zone technique. Refractive index measurements were carried out at four wavelengths as a function of temperature. The measurements show that as the doping concentration of Yb is increased, the refractive index varies marginally for ne whereas there is a significant change in the value of no. The thermo-optic coefficient (dn/dT) was found to be positive with a value ∼10-5/°C, which is 1 order higher than that for the undoped YVO4 crystal. The thermo-optic coefficient is higher for ne compared to that of no. Also, a set of relations describing the wavelength dependence of the thermo-optic coefficient were established that are useful for calculating the thermo-optic coefficient at any temperature in the range 30°C-150°C and at any wavelength in the range 532-1551 nm.

Photoelectrocatalytic activity of immobilized Yb doped WO3 photocatalyst for degradation of methyl orange dye

Pure WO3 and Yb:WO3 thin films have been synthesized by spray pyrolysis technique. Effect of Yb doping concentration on photoelectrochemical, structural, morphological and optical properties of thin films are studied. X-ray diffraction analysis shows that all thin films are polycrystalline nature and exhibit monoclinic crystal structure. The 3at% Yb:WO3 film shows superior photoelectrochemical (PEC) performance than that of pure WO3 film and it shows maximum photocurrent density (Iph=1090µA/cm2) having onset potentials around +0.3V/SCE in 0.01M HClO4. The photoelectrocatalytic process is more effective than that of the photocatalytic process for degradation of methyl orange (MO) dye. Yb doping in WO3 photocatalyst is greatly effective to degrade MO dye. The enhancement in photoelectrocatalytic activity is mainly due to the suppressing the recombination rate of photogenerated electron-hole pairs. The mineralization of MO dye in aqueous solution is studied by measuring chemical oxygen demand (COD) values.