Ion Doping Concentration Research Articles

Electrochemical Reduction and Ion Injection of Annealing‐Free SnO2 for High Performance Perovskite Solar Cells

AbstractThe electron transport layer (ETL) plays a crucial role for efficiency and stability of perovskite solar cells (PSCs). As a promising low‐temperature ETL, tin oxide still requires complicated surface chemical decoration or heat‐treatments to further passivate the defects and adjust band energy level to improve the optoelectronic performance of the device. Herein, a novel and efficient strategy is developed for the solution prepared annealing‐free SnO2 ETL for PSCs. Through simple electrochemical regulation, the elemental composition, valence ratio of Sn, concentration of oxygen vacancies, hydroxyl groups, and dopant ions are precisely modified with the optimized the energy band, reduce the defect density, and enhance high carrier transport for PSCs. Thus, an increase of power conversion efficiency (PCE) from 21.6% to 24.7% and a high VOC of 1.19 V is obtained. The modified devices maintain 95% of the initial PCE after 2000 h of storage, and 80% of the initial PCE after 900 h of aging in an atmospheric environment at 75 °C and RH 20 ± 5%. Moreover, the perovskite solar module based on the as made SnO2 achieve a high PCE of 21.3%.

Effect of cerium substitution on structural and optical properties of barium titanate ceramics

Barium titanate shows interesting behavior with little modification in synthesis route and variation in doping concentration. Barium titanate being perovskite material belongs to ABO3 family, shows tetragonal structure. In this present work, BaTiO3 with varying doping concentration of CeO2 (2 wt%) was fabricated by solid state reaction method. Structural and morphological study reveals a change in crystallite size and grain growth. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and a UV–VIS spectrophotometer were used to characterize the samples. Phases of the prepared samples were investigated by X-ray diffraction. The results of the investigation shows that pure barium titanate have no secondary phases. Pure form of barium titanate shows polycrystalline nature. Further, crystallite size, stress and strain for the doped sample were calculated using Scherrer method, Williamson-Hall analysis, Uniform deformation model (UDM), Uniform stress deformation model (USDM) and Uniform deformation energy density model (UDEDM) approaches. Crystallite size calculated by Scherrer method shows a variation with percentage doping. Doped sample shows reduce in crystallite size. Effect of size and strain induces X-ray peak broadening. In accordance with these findings, FE-SEM measurements demonstrate a shift in grain growth with Ce concentration with respect to pure barium titanate. X-ray diffraction results shows a good agreement with FE-SEM results. Peaks in the absorption are impacted by Ce ion doping concentration. An intriguing behavior of the ceramic is demonstrated by a considerable change in band gap with dopant. Cerium concentrations have a substantial impact on the physical and optical properties.

Modeling the gain spectrum of Bismuth-doped broadband fiber amplifier and its numerical simulation (1200-1600nm)

Broadband fiber amplifiers with materials doped with metal elements as optical media play an irreplaceable and important role in the current network hardware facilities. In this paper, based on the development of broadband fiber amplifiers and previous studies in the reference literature, this study has completed the modeling of gain spectrum of Bismuth-doped broadband fiber amplifier and its numerical simulation, mainly focusing on signal amplification in the 1200-1600nm band, and studied and simulated the relationship between gain spectrum of Bismuth-doped broadband fiber amplifier and fiber length, pumping power and ion doping concentration in this band. In the case of pumping light at a wavelength of 900nm, good gain results were obtained at the central wavelength of 1350nm. The bismuth-doped fiber performs well in terms of gain performance in the spectral range of 1200-1600 nm when the pump power is greater, the fiber length is around 3 m, and the doping concentration is approximately 0.61025. This is a brand-new, highly useful active medium for NIR lasers and fiber amplifiers.

The enhancement of large photochromic coloration contrast with rapid responsive behavior in Ba3MgSi2O8:Dy3+ ceramics for instant information displays

Designing photochromic systems with information displays has been seldom studied but is critical to the realization of instant hand-writable system. Previous instant hand-writable systems with inorganic photochromic materials limited to low color contrast. Herein, by controlling the sintering environment and ion doping concentration, an excellent light response is achieved by engineering the formation of oxygen vacancy defects in Ba3MgSi2O8:0.25%Dy3+, the maximum color contrast as high as 80.7%. A hand-rewritable system fabricated using these photochromic materials exhibits excellent writing and erasing reversibility in response to UV illumination and thermal stimulus. In addition, a large luminescence modulation of 86.2% is achieved due to the well overlap between the emission peak of Dy3+ and the absorption peak of Ba3MgSi2O8. The resulting insights will be useful to researchers in inducing oxygen vacancy defects in high-performance inorganic photochromic systems for superior functional design.

Preparation and Electrochromic Study of Ce3+ Doped TiO2 Thin Films

Ce3+ doped TiO2 thin films were prepared on ITO conductive glass by sol-gel method and dip-coating method using tetrabutyltitanate and glacial acetic acid as raw materials and adding cerium nitrate into cerium. The Ce3+ doped TiO2 powder was characterized by XRD, TG-DTA and SEM. The electrochromic properties of the films were tested by electrochemical workstation. The films were tested by UV-Vis spectrophotometer. Results show that the concentration of doped Ce ions is 2%, and the electrochromic properties of the films are improved greatly. The more the doping is, the more significant the effect on the electrochromic properties of the films is.

Structural,Spectral and Electrical Properties of BaNi2-xZnxFe16O27 Nanoparticles Ferrites

In the current study, w-type BNF-NPs synthesis via ceramic method.the effects of zinc ions doping on the physical properties of BNF-NPs were analyzed. The formation of BNF-NPs emphasized by XRD, FTIR, UV-Visible spectroscopy and electrical conductivity measurement. The phases structure , crysttallite size and lattice parameters wrere evaluated using XRD results. Hexagonal structure with a single phase apeares, the average grain size was found to be in Nano scale from 32 to 34 nm, while the lattice parameters increased slolly as the doping concentration of zinc ions increases. The spectra of FTIR showed main absorption bands which confirmed formation of hexagonal ferrite phase. UV-VIS analysis was also performed and found that the band gaps were in the semiconducting region and increased with increasing zinc concentration. The AC conductivity of the samples decreased with increasing zinc content and showed a dependence on the frequency and temperature. Additionally, as frequency increase the σac conductivity showed dispersion that decreased as temperature increased.dispersion decreases as the temperature increases.

Preparation and scintillation properties of Ce3+/Tb3+-co-doped oxyfluoride glass for high-resolution X-ray imaging

Scintillator glasses have the potential for X-ray imaging owing to their low production cost, controllable shape and size, and uniform ion-doping concentration. In this study, Tb3+-doped and Ce3+/Tb3+-co-doped oxyfluoride scintillator (C4T9) glass samples were fabricated by high-temperature melting and quenching. In addition, the luminescence properties of the glass samples and the discrepancy in the energy transfer mechanism between Ce3+ and Tb3+ under ultraviolet (UV) light and X-ray excitation were investigated. The C4T9 glass sample showed excellent integral scintillation efficiency of 84.1% for commercial Bi4Ge3O12 (BGO) crystals. The spatial resolution of the C4T9 glass sample was higher than that of the commercial BGO crystal with 42.29 mGy s−1 X-ray irradiation, reaching 16 lp·mm−1. C4T9 glass is expected to become a key material in medical imaging, safety inspection, industrial inspection, and other fields.

The role of Nd3+ concentration in the modulation of the thermometric performance of Stokes/anti-Stokes luminescence thermometer in NaYF4:Nd3+

The growing popularity of luminescence thermometry observed in recent years is related to the high application potential of this technique. However, in order to use such materials in a real application, it is necessary to have a thorough understanding of the processes responsible for thermal changes in the shape of the emission spectrum of luminophores. In this work, we explain how the concentration of Nd3+ dopant ions affects the change in the thermometric parameters of a thermometer based on the ratio of Stokes (4F3/2 → 4I9/2) to anti-Stokes (4F7/2,4S3/2 → 4I9/2) emission intensities in NaYF4:Nd3+. It is shown that the spectral broadening of the 4I9/2 → 4F5/2, 2H9/2 absorption band observed for higher dopant ion concentrations enables the modulation of the relative sensitivity, usable temperature range, and uncertainty of temperature determination of such a luminescent thermometer.

Physical and spectroscopic properties of PbO –ZnF2 – B2O3 glasses doped with CuO

The glass samples with the chemical composition of PbO − ZnF2 − B2O3: CuO has been prepared by melt quenching technique. All the prepared glass samples exhibits amorphous nature, were confirmed by the X-ray diffraction studies. The density of the glass samples were measured by using Archimedes’ principle. With help of measured densities various physical properties such as average molecular weight (M¯), molar volume, Interatomic distance(ri), dopant ion concentrations (Ni) were calculated by using standard formulas. Optical Absorption spectra studies reveals that the glass samples contains Cu ions exhibits a broad absorption band at about 780 nm due to 2B1g→2B2g transition.The spectra of Infrared transmission show prominent bands at wave numbers around 1200 to 1400 cm−1, which are caused by the trigonal BO3 units, at 1000 and 1200 cm-1which are caused by vibrations of BO4 structural units, and at about 700 cm−1 which are caused by B-O-B linkages.

Magnetic, Phonon and Optical Properties of Transition Metal and Rare Earth Ion Doped ZnS Nanoparticles.

The surface, size and ion doping effects on the magnetic, phonon and optical properties of ZnS nanoparticles are studied based on the s-d model including spin-phonon and Coulomb interaction, and using a Green's function theory. The changes of the properties are explained on a microscopic level, due to the different radii between the doping and host ions, which cause different strains-compressive or tensile, and change the exchange interaction constants in our model. The magnetization increases with increasing small transition metal (TM) and rare earth (RE) doping concentration. For larger TM dopants the magnetization decreases. The phonon energies increase with increasing TM, whereas they decrease by RE ions. The phonon damping increases for all doping ions. The changes of the band gap energy with different ion doping concentration is also studied. Band gap changes in doped semiconductors could be due as a result of exchange, s-d, Coulomb and electron-phonon interactions. We have tried to clarify the discrepancies which are reported in the literature in the magnetization and the band gap energy.

Study of the effect of lanthanum and cerium doping combination on magnetic properties of M-type hexaferrite oxide permanent magnets

A study has been carried out on the effect of combination of Lanthanum and Cerium doping on the magnetic properties of M-Type hexaferrite permanent magnet oxide. The research was conducted using the wet mechanical milling method. The research materials used were Fe2O3, BaCO3, La2O3, and CeO2, all of which were of high purity 99.9%. This research also uses technical materials such as Ethanol and Nitrogen. Stoichiometric calculations were carried out to calculate the composition of the mixture of each ingredient. The combination of Lanthanum and Cerium substitution was varied with the composition of the doping ion concentration (x = 0 – 0.5 and y = 0 – 0.1). Permagraph characterization was carried out to determine the magnetic properties of each test sample. Results based on the permagraph characterization, the properties of M-type hexaferrite permanent magnets increased with the increase in the doping ion concentration in the sample. The presence of doping ions that have a magnetic moment is strongly suspected to contribute to the interaction of the type and the total moment in the M- type hexaferrite structure.

Effect of Zr4+ concentration on the segregation coefficient and exposure energy of Zr:Fe:Cu:LiNbO3 crystal

A series of Zr:Fe:Cu:LiNbO3 crystals with distinct Zr4+ ion doping concentrations (0, 2, and 4 mol%) were grown using the Czochralski method. Subsequently, the segregation coefficient of doped ions in the crystal was analyzed by an inductively coupled plasma-atomic emission spectrometer. The lattice constant and defect structure of the crystal were measured by X-ray powder diffraction. The light-induced scattering of Zr:Fe:Cu:LiNbO3 crystal was analyzed by the threshold effect of incident exposure energy flux and the same as the change in Zr4+ ion doping concentration. When the Zr4+ ion concentration changes to 4 mol%, the exposure energy was close to 811.37 J/cm2, which is about 192 times that of the 0 mol% Zr4+.

Structural, Spectroscopic, and Biological Characterization of Novel Rubidium(I) and Europium(III) Co-Doped Nano-Hydroxyapatite Materials and Their Potential Use in Regenerative Medicine.

This research investigates hydrothermally synthesized hydroxyapatite nanoparticles doped with rubidium(I) and europium(III) ions. Investigation focused on establishing the influence of co-doped Eu3+ and Rb+ ions on hydroxyapatite lattice. Therefore, structural, and morphological properties were characterized via using X-ray powder diffraction (XRPD), infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM), as well as transmission electron microscopy (TEM) techniques. Furthermore, this investigation evaluates the impact of various Rb+ ion doping concentrations on the distinct red emission of co-doped Eu3+ ions. Hence, luminescence properties of the obtained materials were evaluated by measuring emission excitation, emission spectra, and luminescence decays. As established by numerous studies, synthetic hydroxyapatite has excellent application in biomedical field, as it is fully biocompatible. Its biocompatible makes it highly useful in the biomedical field as a bone fracture filler or hydroxyapatite coated dental implant. By the incorporation of Eu3+ ions and Rb+ ions we established the impact these co-doped ions have on the biocompatibility of hydroxyapatite powders. Therefore, biocompatibility toward a ram's red blood cells was evaluated to exclude potential cytotoxic features of the synthesized compounds. Additionally, experimental in vitro bioactive properties of hydroxyapatite nanoparticles doped with Rb+ and Eu3+ ions were established using a mouse osteoblast model. These properties are discussed in detail as they contribute to a novel method in regenerative medicine.

Thermoluminescence of hydroxyapatite from eggshell powders doped with Dy synthesized by the sonication chemical method: Effects of doping concentration and heating rate

Hydroxyapatite (HAP) was selected as the host material and synthesized using a sonication chemical method. The effect of Dy3+ ion doping concentrations (0.25, 0.5, 1, 2, 3, 4, 5, 7, and 10 wt%) on the structure and thermoluminescence was examined. The TL properties of Dy3+ doped HAP were also studied, including dose response, repeatability, and heating rate. Based on the glow curves of samples with a heating rate of 2 °C/s after beta irradiation to 20 Gy, three effective peak maxima appeared to make up the glow curves located at around 84, 190, and 318 °C. However, four levels of activation energy were observed by Tm-Tstop analysis. The kinetic analysis of four peaks obtained via computerized glow curve deconvolution revealed trap depths of 0.80, 0.95, 1.20, and 1.51 eV, with corresponding frequency factors of 1010, 1011, 1012, and 1011 s−1, respectively. Parallel investigations using the initial rise and variable heating rate approaches yielded comparable trap depth estimates. The dose dependence of the glow curves was determined to be linear across the 0.1–20 Gy range.

ZnO Nanostructures Doped with Various Chloride Ion Concentrations for Efficient Photocatalytic Degradation of Methylene Blue in Alkaline and Acidic Media.

In this study, chloride (Cl−) ions were successfully doped into ZnO nanostructures by the solvothermal method. The effect of various Cl− concentrations on the photocatalytic activity of ZnO towards the photodegradation of methylene blue (MB) under the illumination of ultraviolet light was studied. The as-prepared Cl−-doped ZnO nanostructures were analyzed in terms of morphology, structure, composition and optical properties. XRD data revealed an average crystallite size of 23 nm, and the XRD patterns were assigned to the wurtzite structure of ZnO even after doping with Cl−. Importantly, the optical band gap of various Cl ion-doped ZnO nanostructures was successively reduced from 3.42 to 3.16 eV. The photodegradation efficiency of various Cl− ion-doped ZnO nanostructures was studied for MB in aqueous solution, and the relative performance of each Cl ion-doped ZnO sample was as follows: 20% Cl−-doped ZnO > 15% Cl−-doped ZnO > 10% Cl−-doped ZnO > 5% Cl−-doped ZnO > pristine ZnO. Furthermore, the correlation of the pH of the MB solution and each Cl ion dopant concentration was also investigated. The combined results of varying dopant levels and the effect of the pH of the MB solution on the photodegradation process verified the crucial role of Cl− ions in activating the degradation kinetics of MB. Therefore, these newly developed photocatalysts could be considered as alternative materials for practical applications such as wastewater treatment.

Enhancing red upconversion emission in NaErF4@NaYF4 core-shell nanoparticles by introducing Yb3+ ions as energy trapping centers

Rare-earth-doped red upconversion nanocrystals (UCNPs) have shown excellent prospects for application in biological imaging, labeling and other fields. In this work, NaErF4@NaYF4 core-shell (CS) UCNPs were successfully constructed to enhance red emission by introducing Yb3+ ions as energy trapping centers under different near-infrared excitation wavelengths. The experimental results showed that the red upconversion emission intensity of NaErF4@ NaYF4 CS UCNPs doped with 15%Yb3+ ions in the core is nearly 202 times higher than that of NaErF4 UCNPs under 980 nm excitation wavelength, with a red/green emission intensity ratio of 18.7. When Yb3+ ions were introduced into the core and shell of NaErF4@NaYF4 CS UCNPs, NaErF4:15%Yb3+@NaYF4:10%Yb3+ CS UCNPs showed the best red emission due to the energy network characteristics of the Yb3+ ions. Furthermore, the enhancement mechanism of red emission in NaErF4@NaYF4 CS UCNPs with different Yb3+ ion doping concentrations were discussed, based on the spectral characteristics and lifetime. It was found that doping of Yb3+ ions in NaErF4@ NaYF4 CS UCNPs can significantly improve the red emission intensity of Er3+ ions through controlling energy migration (EM) and energy back transfer (EBT) processes, which has considerable potential for applications in bioimaging and anti-counterfeiting.

The optical properties of Mn4+ ions in Ba2CaWO6 with double perovskite structure for optical thermometer application

A series of red-emitting phosphors Ba2CaWO6:xMn4+ were synthesized by solid-state method. The phosphors were characterized by X-ray diffraction (XRD), photo-luminescent excitation spectra (PLE), photo-luminescent emission spectra (PL), decay curves, and quantum efficiency (QE). The concentration-dependent PL spectra were measured to evaluate the optimum Mn4+ ion doping concentration. The energy transfer behavior between Mn4+ ions or Mn4+ ions and tungstate group [WO6] were measured in details. PL emission spectra recorded at different temperatures were introduced to quantify the thermal stability. The temperature dependent emission intensity ratio values were used in temperature sensing applications in the temperature region of 7 to 510 K. The obtained results indicate that the synthesized phosphors have the possibility to be used as an optical thermometer.

Structural and luminescent behaviour of Dy(III) activated Gd3Al5O12 nanophosphors for white-LEDs applications

Single-phased cool white light emissive Gd3-xAl5O12:xDy3+ (x = 0.01–0.07) nanophosphors have been prepared via gel-combustion method. Diffraction data and Rietveld results have affirmed the development of a single cubic phase of all the prepared samples with space group Ia-3d (230). Furthermore, the crystallite size was calculated through Debye-Scherrer's formula and the Williamson-Hall method. In the EDX spectrum, the nonappearance of peaks analogous to the foreign elements affirms the pure synthesis of the considered phosphors. TEM observation reveals agglomerated porous crystalline material with non-uniform shapes and varying particle size in 20–80 nm range. Fourier Transform Infrared (FTIR) spectroscopy has been applied for the examination of chemical bonding with other vibrational characteristics. The luminescence study confirms the intense blue and yellow emission of synthesized phosphors at 482 nm and 576 nm respectively owing to 4F9/2→6HJ (J = 15/2, 13/2) transitions. Moreover, the detailed evaluation of the concentration quenching process established that dipole-quadruple interaction is answerable for the decrease in luminescence intensity after optimum dopant ion concentration. The chromatic analyses recommend that emission from the optimized nanophosphors lies in the region of cool white light. The outcomes of the present investigation propose that Gd3Al5O12:Dy3+ phosphors might be a potential candidate for white-LEDs applications.

High efficiency and high beam quality Er:YSGG Mid-infrared continuous-wave laser

We demonstrated an LD end-pumped Er:YSGG mid-infrared (MIR) continuous-wave (CW) laser based on optimized LD pump wavelength with less absorption coefficient and thermal problems. A composite crystal YSGG/Er:YSGG/YSGG with a size of 3 × 3 × 14 (2 + 10 + 2) mm3 was employed, and its central part had an erbium ion doping concentration of 38 %. The maximum output power of 2.8 μm MIR laser is 2.01 W, corresponding to a slope efficiency of 28.89 %, at which the beam quality M2 of the laser is 1.19. Compared with other Er3+-doped laser, we achieved a CW MIR laser with higher efficiency and better beam quality. The results suggest that optimizing the wavelength of the pump source and adopting the crystal bonding technology could effectively improve the performance of the LD end-pumped Er:YSGG CW MIR laser.

Structural refinement and optical characteristics of single-phase Gd3Al5O12:Er3+ nanophosphors for luminescent applications

Single phase green color emanating Gd3-xAl5O12:xEr3+ (x = 0.01–0.06) nanophosphors have been synthesized through most reliable, environmentally friendly, low temperature based urea assisted gel-combustion process. XRD and Rietveld refinement investigations have confirmed the formation of single phase cubic system with space group Ia-͞3d (230). TEM picture reveals the agglomerated spherical particles of size 18–30 nm. The existence of highly intense band at 278 nm in the excitation spectrum, has confirmed the efficient transfer of energy between Gd3+→Er3+ ions. The emission (PL) spectra, monitored at 278 nm of excitation wavelength show most intensive band at 548 nm which is responsible for the green color of synthesized phosphors. The emission intensity vary with dopant ion concentration and maximum intensity was found at x = 0.03 (optimum concentration). Dipole-dipole interactions between the neighbouring ions are responsible for the quenching of concentration. The chroma-coordinates of the optimized sample (Gd2.97Al5O12:0.03Er3+) are assessed to be 0.314, 0.579 and the analogous correlated color temperature ∼5836.13 K with color purity 91.23% have been calculated. Hence, Gd3-xAl5O12:xEr3+ (x = 0.01–0.06) nanomaterials developed in this work may serve as significant phosphors for luminescent applications.