Optimal Doping Concentration Research Articles

Spectral characteristics and luminescence applications of Eu3+-activated fluorosilicate Na2MgGd2[SiO3]4F2

This work reports the luminescence spectra and application of novel Eu3+-doped Na2MgGd2[SiO3]4F2 phosphor. The X-ray powder diffraction confirmed the pure phase formation of the samples with the monoclinic space group P21/c (No:14). The phosphors demonstrated efficient red emission at 613 nm from the electric dipole transitions 5D0→7F2. The optimal doping concentration was found to be approximately 25 mol%. Na2MgGd2[SiO3]4F2:0.25Eu3+ exhibits a high quantum efficiency (QE) of 57 % with excellent thermal stability and pure chromaticity. Red- and the white light-emitting diode devices were packaged using InGaN chips and Na2MgGd2[SiO3]4F2:0.25Eu3+. The fabricated WLED has CIE coordinates of (x = 0.33, y = 0.34), which are very close to the white point in the National Television System Committee (x = 0.33, y = 0.33). The color rendering index (CRI, Ra) and correlated color temperature (CCT) of the WLED are 91 and 4400 K, respectively. The results show that as a red luminescent phosphor, it is a potential candidate for the preparation of near-UV/blue InGaN-based WLEDs.

First‐Principles Study of the Effects of High‐Order Anharmonicity on the Thermal Transport Properties and Thermoelectric Effects in the Lattice Dynamics of 12 New Full–Heusler Compounds X2YTe (X = Na, K, Rb, Cs; Y = Zn, Cd, Hg)

AbstractIn this study, advanced first‐principles calculations combined with self‐consistent phonon theory and the Boltzmann transport equation are used to assess the thermoelectric properties of novel Full–Heusler materials X2YTe (X = Na, K, Rb, Cs; Y = Zn, Cd, Hg). These materials exhibit low formation energies, facilitating synthesis under standard conditions. This analysis showed that lattice anharmonicity increases with the atomic mass of X and decreases with the atomic mass of Y due to the rattling effect of Y atoms. Significant rattling effects are identified, prompting the inclusion of higher‐order anharmonic effects. By renormalizing the phonon spectrum and accounting for three‐phonon and four‐phonon scattering, the mechanisms behind the low lattice thermal conductivity in these compounds is uncovered. The combination of low lattice thermal conductivity and high power factors resulted in remarkable thermoelectric figure of merit values at optimal doping concentrations and temperatures. Notably, except for Na2ZnTe and Na2HgTe, all other materials surpassed the long‐standing figure of merit record of less than 3, with Rb2ZnTe achieving a figure of merit of 8.11 at 700 K with an n‐type doping concentration of 2 × 1019. The inclusion of spin‐orbit coupling led to less than a 10% reduction in the thermoelectric figure of merit, underscoring the superior thermoelectric performance of these materials.

Improved transparency and charge matching of electrochromic devices with Ce-doped NiO counter electrode

The quest for cost-effective and efficient electrochromic electrodes, featuring high color contrast and rapid response times, has sparked increasing interest in research of metal oxides for electrochromic applications. In this study, nickel oxide thin films with various cerium dopant concentrations are synthesized, with the optimized doping concentration identified as 1 at%. X-ray diffraction analysis confirmed that the dopant successfully reduces crystal size and alters the preferred orientation to (111). The 1 % Ce:NiO thin film exhibits enhanced electrochromic performance, with a transmittance modulation increase of 27.4 % at 633 nm, a 27.1 % rise in coloration efficiency and faster response time (tb=9.64 s and tc=6.76 s) compare to the undoped NiO. Importantly, the charge density of 1 % Ce:NiO thin film increases from 4.86 to 8.14 mC cm−2, representing a 67.5 % improvement, which becomes a better charge matching with WO3 in electrochromic devices. The incorporation of Ce into the NiO thin films not only leads to increased transmittance in the bleached state and optical modulation in the electrochromic devices but also contributes to a rise in the optical band gap of the NiO thin films and improved charge balance matching. These results underscore the positive impact of cerium doping on microstructure and electrochromic performance, indicating a promising future for electrochromic devices.

Cutting-edge applications of oleic acid-modified CdSiO3: Ce3+ phosphors: Artificial intelligence enhanced latent fingerprint detection, anti-counterfeiting and optical thermometry

A series of (1–11 mol%) Ce³⁺ doped CdSiO₃ phosphors are synthesized via a solution combustion method, and the sample with the optimal doping concentration underwent surface modification with oleic acid (OA). X-ray diffraction (XRD) analysis confirmed the formation of high-purity, well-crystallized CdSiO3:Ce3+ phosphors. Upon 347 nm UV excitation, the phosphor exhibited intense blue emission at 400 nm, with an optimized Ce³⁺ concentration of 5 mol%, attributed to dipole-dipole interactions. The OA-modified phosphor demonstrated significantly enhanced properties, achieving a color purity (CP) of 97.2% and Internal quantum efficiency (IQE) of 82.5%. The phosphor also exhibited excellent thermal stability, retaining 93.0% of its emission intensity at 423 K and a thermal quenching temperature exceeding 483 K, with a high activation energy (Eₐ) of 0.384 eV. In practical applications, the OA modified phosphor showed exceptional performance in latent fingerprints (LFPs) detection and anti-counterfeiting (AC) across different substrates, offering high resolution, contrast, and minimal background interference. MATLAB based analysis yielded a matching score of 94.52%, surpassing conventional benchmarks, underscoring the phosphor's potential for advanced fingerprint identification. These results demonstrate that the CdSiO₃:5Ce³⁺ phosphor is a promising candidate for applications in white light-emitting diodes (w-LEDs), optical thermometry, forensic analysis and AC technologies.

Inspection and comparative analysis of light and thermal response dynamics of Cu/V₂O₅/n-Si and Cu/La-V₂O₅/n-Si MIS diodes

Schottky Barrier Diodes (SBDs) are pivotal in modern electronics for their quick switching and low forward voltage drop, enabled by metal-semiconductor junctions. SBDs are renowned for their performance, primarily due to their metal-semiconductor intersection. This study focuses on Cu/V2O5/n-Si and Cu/La-V2O5/n-Si SBDs, examining the impact of lanthanum doping on their performance. Transition Metal Oxides (TMOs) like Vanadium Pentoxide (V2O5) offer unique electronic, magnetic and optical properties making them suitable for various applications. The fabrication process involved sol-gel spin coating and DC magnetron sputtering to create a thin V2O5 layer on n-type silicon wafers, followed by copper contact deposition. Galvanizing temperatures ranged 300° C to 500° C to study the structural, optical, and morphological changes in V2O5 thin films. Key findings include the significant reduction in ideality factor (n) with increasing annealing temperatures for Cu/V2O5/n-Si SBDs, reaching as low n value of 5.26 at 500°C, indicating improved device performances. For Cu/La-V2O5/n-Si SBDs, the ideality factor consistently decreased with higher light intensities, showcasing enhanced performance due to La doping. Barrier height (ɸB) also varied, with higher values observed for La-doped V2O5, enhancing charge recombination and increasing oxygen vacancies. Photodiode parameters were significantly enhanced by doping of the La. The Cu/La-V2O5/n-Si SBDs demonstrated high photosensitivity (PS = 3327.5 %), photo responsivity (R = 33.39 mA/W) and detectivity (D* = 9.82 × 10¹⁰ Jones), making them highly efficient for optoelectronic applications. Overall, this study highlights the potential of Cu/La-V2O5/n-Si SBDs for high-efficiency, optoelectronic applications, with optimized doping concentrations and annealing conditions significantly improving their performance.

Double modulation of the electric field in InGaAs/Si APD by groove rings for the achievement of THz gain-bandwidth product

Abstract Avalanche photodiode (APD) is commonly used as a receiver in optical communication and light detection and ranging (LIDAR), offering highly sensitive photodetection capabilities. A key strategy for improving the gain-bandwidth product (GBP) of the APD involves the optimization of the electric field distribution using the charge layer. However, traditional modulation methods to adjust the carrier transport and avalanche process using the charge layer often face challenges (inefficiency and non-uniformity). An InGaAs/Si APD based on the wafer bonding method with a GBP up to 1.03 terahertz (THz) is reported theoretically in this work. The charge layer and groove rings are inserted at the InGaAs/Si bonded interface to modulate the electric field in the APD effectively, demonstrating low dark current and reduced avalanche bias of the device. This approach induces a dramatic and rapid variation of the electric field at the interface while reducing the gradient of the electric field in the multiplication layer. Additionally, the indirect impact of the groove ring on mitigating the adverse effects of the lattice mismatch is pointed out, and the optimal doping concentration range of the charge layer is identified to enhance the modulation effect of the electric field for stronger impact ionization. These findings provide valuable insights for the next-generation InGaAs/Si APDs with high GBP for high-speed data transmission.

White emitting Sr3Ga2Ge4O14: Dy3+ phosphors with high purity and good thermal stability

A series of white emitting phosphors Sr3Ga2Ge4O14: xDy3+ (x = 1, 3, 5, 7, 9 and 11 %) were synthesized by a high-temperature solid-phase method. All samples exhibit two emission peaks at 478 nm and 571 nm, corresponding to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions of Dy3+ ions, respectively. The optimal doping concentration of Sr3Ga2Ge4O14: xDy3+ phosphors was determined as 7 % mol, and the concentration quenching mechanism is confirmed as a dipole–dipole interaction. Finally, the temperature dependent luminescence spectra indicate that the synthesized Sr3Ga2Ge4O14: 7 % Dy3+ phosphors had good thermal stability.

Preparation and properties of GdPO4:Dy3+ phosphors and ceramics with high thermal stability

In this work, Gd1-xPO4:xDy3+ powders were synthesized by calcining the mixed raw materials at 1273 K and the optimal doping concentration was determined. Then the optimized composition powders were fabricated as ceramics after granulation, pressing and sintering. Meanwhile, the luminescent properties of the phosphors and ceramics, especially the thermal stability, were discussed. The results revealed that Gd1-xPO4:xDy3+ exhibited two strong emission peaks of blue light and yellow light under the excitation of 349 nm, ascribed to the energy level transition from 4F9/2 to 6H15/2 and 6H13/2 of the electrons of Dy3+, and the color coordinates were located in the white light region. The optimal doping concentration of Dy3+ was found as 0.1, and the electronic dipole-dipole interaction contributed to the concentration quenching. It was noted that the phosphors had good thermal stability. Specifically, the thermal stability was further improved after the ceramics was formed and the relative intensity between the blue and yellow changed the opposite, indicating different occupation sites of Dy3+.

Preparation, structure and spectral properties of Eu3+-doped Lu2O3 scintillation ceramics

Lu2O3 scintillation ceramics doped with different concentrations of Eu3+ were prepared by SPS in a vacuum environment. The microstructural properties of the prepared ceramics were analyzed using XRD, SEM and EDS in details. Excited by the 395 nm, the Eu3+-doped samples display a prominent emission peak at 612 nm, corresponding to the transition 5D0→7F2. The PL spectra across various concentrations identified 3 at.% as the optimal doping concentration. The temperature-dependent PL spectra reveal the activation energy of approximately 0.266 eV for the 3 % Eu3+-doped Lu2O3 ceramic. Under 395 nm excitation, the lifetimes of xEu:Lu2O3 (x = 0.01, 0.03, 0.05 and 0.07) ceramics were fitted to be 1.07 ms, 1.02 ms, 0.99 ms and 0.92 ms, respectively. The XEL spectra of Eu3+-doped samples are consistent with their PL spectra, aligning well with the sensitivity range of the detector. These results demonstrate that Eu3+:Lu2O3 scintillation ceramics are ideal materials for scintillation detectors.

Novel Tm3+/Dy3+ co-doped CaMoO4 transparent glass-ceramic phosphor for white LED applications

To develop new inorganic luminescent materials, a set of Dy3+/Tm3+ co-doped molybdate precursor glasses (PGs) were manufactured using the conventional melting method, and a novel CaMoO4 transparent fluorescent glass-ceramic (GC700-2 h) was achieved via controlled crystallization of PG at 700 ℃ for 2 h. The luminescent color of the glass phosphor was facilely modulated by varying the doping levels of Dy3+ and Tm3+. The glass phosphor with optimal doping concentration of 0.6Dy3+ and 0.6Tm3+ exhibits a color coordinate of (0.3334, 0.3107). Compared with PG, the luminous intensity and quantum yield of GC700-2 h sample is obviously increased, and GC720-2 h sample displays the color coordinate (0.3292, 0.2852), belonging to the standard white light region. Moreover, GC720-2 h sample possesses good thermal stability in fluorescence property. The white LED lamp encapsulated with GC720-2 h exhibits color temperature of 7564 K and color rendering index of 75.3. These results clearly show that the 0.6Dy3+/0.6Tm3+ co-doped glass and CaMoO4 glass-ceramic could be used as potential candidate material in the field of white light-emitting diodes.

Sm3+ activated Ba3LaNa(PO4)3F fluorophosphate phosphor: Synthesis, characterization and their photoluminescence investigation for warm WLEDs

In this present research report, the series of Ba3LaNa(PO4)3Fphosphor doped with Sm3+ was successfully synthesized by using a high-temperature solid-state reaction method. The phase purity was examined using X-ray diffraction (XRD), which confirmed a pure phase of prepared material after sintering the sample at 700 °C. Fourier transform infrared (FT-IR) spectra showed absorption bands corresponding to the stretching and vibrational modes of PO4 in phosphate. Scanning electron microscopy (SEM) images displayed the morphology of sample and agglomerated structure of micron-sized particles. Photoluminescence excitation (PLE) and emission spectra of the Ba3LaNa(PO4)3F: Sm3+ phosphors were studied. When excited with near-UV light, the phosphor showed three prominent peaks at 567, 604, and 643 nm. The emission spectra for different concentrations of Sm3+ ions were also measured to find the optimal dopant concentration. The highest intensity was observed at a 2.0 mol% concentration of Sm3+ ions at 604 nmwith concentration quenching occurring beyond this point. The CIE chromaticity coordinates for the different concentration phosphor were located in the orange-red region, indicating its characteristic light emission. So therefore, these results suggested that the synthesized reddish-orange light-emitting Ba3LaNa(PO4)3F: Sm3+prepared phosphor is promising for applications in white light-emitting diodes (WLEDs).

Dual-Functional Tungsten-Doped NiO for Highly Sensitive Triethylamine Sensor with ppb Level Detection Limit.

In this study, the W-doped Nickel oxide (NiO) nanoflowers were synthesized using a straightforward hydrothermal method, significantly enhancing the sensing performance toward triethylamine through dual-functional tungsten doping. The optimal doping concentration not only increased the specific surface area of NiO from 25.54 to 189.19 m2 g-1 but also reduced the formation energy of oxygen vacancies. The sensor containing 4 at % W-doped NiO demonstrated exceptional sensitivity to triethylamine, achieving a detection level as high as 229.0 for concentrations of 100 ppm at 237.5 °C. This triethylamine sensor represents a 135-fold enhancement over sensors fabricated from undoped NiO, and offers a rapid response/recovery time of 8 and 30 s, respectively. Furthermore, at a lower triethylamine concentration of 50 ppb, indicating a lower detection limit.

Development of Mg2TiO4:Mn4+ phosphors for enhanced red LED emission and forensic fingerprint analysis

The advancement in the development of inorganic phosphors marks a significant milestone in the fields of LED technology and forensic science. Herein, Mg2TiO4:Mn4+ (MTO:Mn4+) novel red-emitting phosphors are synthesized through a solvothermal method, which demonstrates a promising approach for enhancing latent fingerprint detection capabilities and improving the performance of red LEDs. The confirmation of the cubic structure post-annealing and the nano-nature as revealed by TEM analysis underpin the MTO:Mn4+ phosphors suitability for these applications. The broad excitation spectra and the sharp red emission at 659 nm, coupled with the optimal doping concentration, showcase the MTO:Mn4+ phosphor's efficient luminescence properties. Moreover, the calculated critical distance between Mn4+ ions (32.906 Å) elucidates the concentration quenching mechanism, which is pivotal for optimizing the performance. The high purity of the emitted red light (97.2 %) and the precise CIE coordinates (0.5969, 0.2926) of the MTO:Mn4+ phosphor suggest its potential for producing high-quality red LEDs. Additionally, the capability of MTO:Mn4+ phosphors to reveal detailed and high-resolution latent fingerprints offers a more reliable and efficient method for processing and analyzing crucial evidence. These findings not only contribute to the scientific understanding of MTO:Mn4+ phosphor materials but also pave the way for their practical application in cutting-edge technologies.

Excellent thermoelectric performance in alkali metal phosphides M3P (M = Na and K) with phonon-glass electron-crystal like behaviour.

Identifying ideal thermoelectric materials presents a formidable challenge due to the intricate coupling relationship between thermal conductivity and power factor. Here, based on first-principles calculations, along with self-consistent phonon theory and the Boltzmann transport equation, we theoretically investigate the thermoelectric properties of alkali metal phosphides M3P (M = Na and K). The evident 'avoided crossing' phenomenon indicates the phonon glass behavior of M3P (M = Na and K). Due to the strong lattice anharmonicity induced by alkali metal elements, accounting for quartic anharmonic corrections, the lattice thermal conductivities of Na3P and K3P at room temperature are merely 0.25 and 0.12 W m-1 K-1, respectively. Furthermore, the high degeneracy and 'pudding-mold-type' band structure lead to high p-type PF in M3P (M = Na and K). At 300 K, the p-type power factors (PF) of Na3P and K3P can reach 3.90 and 0.80 mW mK-2, respectively. The combination of ultralow κL and high PF leads to excellent thermoelectric figure of merit (ZT) values of 1.70 (3.38) and 1.18 (2.13) for p-type Na3P and K3P under optimal doping concentration at 300 K (500 K), respectively, surpassing traditional thermoelectric materials. These findings demonstrate that M3P (M = Na and K) exhibits behavior similar to phonon-glass electron crystals, thereby indicating a direction for the search for high-performance thermoelectric materials.

Novel Orange-Emitting YPO4:Sm3+/Polymer Nanocomposite Phosphor Films for LED Applications.

A polymer based nanocomposite (NC) material embedded with highly luminescent nanopowders could be promising for replacing traditional luminescent materials from a technological pointof view.In this study, we have successfully obtained YPO4: Sm3+ /Polymer nanocomposite phosphor films by embedding YPO4: Sm3+ luminescent nanoparticles (NPs) for orange-light emitting diode (LED) applications. These luminescent NPs were synthesized using the sol gel method in different polymer matrices i.e. polystyrene (PS) and poly (methyl methacrylate) (PMMA) by using direct solution mixing. The structural, morphological, and photoluminescence characteristics of the nano-phosphors and resulting NC films were examined and discussed. The emission spectra of YPO4: Sm3+ (x at.%) nano-phosphors under near-UV excitation at 404nm were dominated by orange emission attributed to 6H5/2 4F7/2 (601nm) luminescence of Sm3+ ions. The optimum doping concentration of activator Sm3+ in YPO4 matrix was found to be 5 at.%. When the doping concentration of Sm3+ was higher than 5 at.%, concentration quenching occurred. The incorporation of YPO4: Sm3+ NPs into polymer matrices indicated that the NCs retained the original luminescence properties of the luminescent NPs, although a decrease in their emission intensity was observed for the NC films, attributable to a polymer matrix effect, which dominated in PS matrix. The fluorescence decay times of NPs in the NC films were measured and compared to those of proper YPO4: Sm3+ nano-phosphors. A decrease in decay time in NC film was observed due the effective refractive index effect. Temperature-dependent photoluminescence (TDPL) of PMMA NC film was studied in 100-400K range, investigating the thermal stability of the film. Additionally, CIE coordinates confirmed the red-orange light emission of the prepared phosphors and NC films. The obtained results indicate that the synthesized polymer-nanophosphor NC films are promising candidates for orange-LED applications.

Synthesis and upconversion color Tunability luminescence of K5Yb(MoO4)4 phosphor doped with Er3+and optical temperature sensing applications

A series of double molybdates with palmierite-related structure phosphors K5Yb1-x (MoO4)4:xEr3+ were synthesized by a solid-state method. It has been demonstrated that the K5Yb1-x (MoO4)4: xEr3+ phosphors are capable of exhibiting the characteristic green and red UC emission of Er3+ ions with excitation at 980 nm. Moreover, the green light emission is far more than the red light emission, so that the sample emits a powerful green light, which belongs to the two-photon absorption process. The upconversion efficiency is peaked when the content of Er3+ ions is 10 mol %. The optical thermometry properties of phosphors were explored by observing that the green UC emission intensity is temperature dependent. The maximum sensor sensitivity of the studied phosphor was discovered to be about 1.61%K−1 at the optimum doping concentration. And the phosphor is demonstrated to have high thermal stability by temperature cycling test. Eventually, a green light-emitting diode device was realized by using synthesized particles and a 980 nm near-infrared chip, which can emit a more obvious green light when the voltage reaches 1.80 V and the current can reach 800 mA, thus confirming its applicability in solid-state lighting. And the LED devices have been tested for life stability with little or no light degradation. These properties make the phosphors not only suitable for non-contact optical temperature measurement, but also able to be applied to solid state lighting.

Analysis of structural defects and their influence on red-emitting γ-Al2O3:Mn4+,Mg2+ nanowires using positron annihilation spectroscopy.

The present paper reported on the analysis of structural defects and their influence on the red-emitting γ-Al2O3:Mn4+,Mg2+ nanowires using positron annihilation spectroscopy (PAS). The nanowires were synthesized by hydrothermal method and low-temperature post-treatment using glucose as a reducing agent. X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), and photoluminescence excitation (PLE) were utilized, respectively, for determining the structural phase, morphology and red-emitting intensity in studied samples. Three PAS experiments, namely, positron annihilation lifetime (PAL), Doppler broadening (DB), and electron momentum distribution (EMD), were simultaneously performed to investigate the formations of structural defects in synthesized materials. Obtained results indicated that the doping concentration of 0.06% was optimal for the substitution of Mn4+ and Mg2+ to two Al3+ sites and the formation of oxygen vacancy (VO)-rich vacancy clusters (2VAl + 3VO) and large voids (~0.7 nm) with less Al atoms. Those characteristics reduced the energy transfer between Mn4+ ions, thus consequently enhanced the PL and PLE intensities. Moreover, this optimal doping concentration also effectively controlled the size of nanopores (~2.18 nm); hence, it is expected to maintain the high thermal conductivity of γ-Al2O3 nanowire-phosphor. The present study, therefore, demonstrated a potential application of γ-Al2O3 nanowire-phosphor in fabricating the high-performance optoelectronic devices.

Er3+ activated BaLaGaO4 multifunctional green phosphors for optical thermometers and WLEDs

Er3+-doped BaLaGaO4 green phosphors was synthesized through a high-temperature solid-state reaction technique. The phase structure and morphology test results of the phosphor indicate that the BaLaGaO4 material was successfully synthesized and Er3+ ions were successfully doped into the main lattice. This doping does change the basic structure of the crystal. BaLaGaO4:Er3+ phosphor exhibits bright green emission centered at 545 nm when excited by 381 nm ultraviolet light or 980 nm near-infrared light. The optimal doping concentration is found to be x = 0.04. To quantify the temperature sensitivity of the phosphor, the fluorescence intensity ratio method was used. Within the temperature range of 298–473 K, the maximum relative sensitivities are 1.35%/K (298 K, 381 nm) and 1.45%/K (298 K, 980 nm), respectively. The maximum absolute sensitivities are 0.67%/K (473 K, 381 nm) and 0.69%/K (473 K, 980 nm), respectively. Finally, white light-emitting diodes (WLEDs) with a high colour index of Ra = 82 and a relatively low correlated colour temperature of CCT = 5064 K are obtained by integrating the synthesized BaLaGaO4:0.04Er3+ green phosphor into warm WLEDs devices. These results suggest that Er3+-activated BaLaGaO4 multifunctional phosphors hold considerable promise in the areas of optical temperature sensing and WLEDs phosphor conversion.

An efficient red phosphor LuNb2VO9:Eu3+ with broadband excitation and abnormal thermal quenching properties for personal identification, security ink, and w-LEDs

A series of red-emitting phosphors LuNb2VO9 (LNV):xEu3+ (x = 0.5–45 mol%) were successfully obtained through the high-temperature solid-state reaction. The structure, phase purity, photoluminescence spectra, thermal stability properties, and color purity of the obtained phosphors were systematically examined. The LNV:Eu3+ phosphor exhibits broadband excitation due to the O2-→Eu3+ and O2-→V5+ charge transfer. The LNV:Eu3+ phosphor excited at 316 nm shows four emission peaks at 595, 615, 619, and 699 nm, corresponding to electron transitions from the 5D0 level to the 7F1, 7F2, 7F3 and 7F4 levels. The optimal doped concentration of LNV:xEu3+ is x = 10 mol%. The quenching mechanism is attributed to the nearest neighbor ion interaction. Furthermore, the prepared phosphor exhibits good thermal stability and remarkable activation energy Ea (0.74 eV). In addition, LNV:Eu3+@oleic acid (OA) readily exhibits the level I-III characteristics of fingerprints and the detailed characteristics of lip lines. The successful utilization of LNV:Eu3+ in anti-counterfeiting ink has yielded impressive results. The Commission International de L′ Eclairage (CIE) coordinate of the prepared white light-emitting diode (w-LED) in this study is (0.331, 0.367), accompanied by a color rendering index (Ra) of up to 95. Notably, the results of these experiments indicate that LNV:Eu3+ phosphor possesses exceptional luminescence properties and holds promising applications.

Enhanced photocatalytic activity of titanium-doped copper ferrite for methyl green dye degradation under commercial visible LED light

This study examines the effect of TiO₂ doping on the catalytic performance of copper ferrite (CuFe₂O₄) nanoparticles in degrading methyl green dye under visible light. Copper ferrite nanoparticles were synthesized and doped with varying TiO₂ concentrations. The catalysts were characterized using XRD, SEM, EDX, and BET surface area analysis. The TiO₂-doped copper ferrite catalysts showed significantly enhanced catalytic activity compared to undoped copper ferrite. The optimal doping concentration of 10 wt% TiO₂ achieved a degradation efficiency of 92 % for methyl green dye after 60 min of irradiation. The BET surface area increased with TiO₂ doping, contributing to the improved catalytic performance. Reusability tests over five cycles indicated a slight decrease in efficiency, attributed to the loss of active sites. These results indicate that TiO₂ doping effectively enhances the catalytic properties of copper ferrite, making it a viable option for environmental remediation.