Mn Phosphor Research Articles

Improved Optical Performance Analysis of YAG:Ce, NCS:Sm, and CAO:Mn Phosphors Physically Integrated with Metal-Organic Frameworks.

This research presents a thorough examination of the optical properties and performance enhancement strategies of synthesized phosphors, namely, yttrium aluminum garnet doped with cerium (YAG:Ce), sodium calcium silicate with samarium (NCS:Sm), and calcium aluminate oxide doped with manganese (CAO:Mn). The study delves into the synthesis processes of the phosphors, illumination of the crystal structures, and enhancement of luminescent characteristics. Additionally, the paper extends to the synthesis and analysis of {[Cu(μ3-dmg)(im)2]·3H2O} n (PKY159), and the coordination polymer (CP) was added the phosphors to explore a novel approach for enhanced optical performance. When the phosphor composites YAG:Ce, CAO:Mn, and NCS:Sm were made as poly(methyl methacrylate) (PMMA; for homogenization, stabilization) thin films with the coordination polymer PKY159 included, the intensity values increased by 97%, 96%, and 79%, respectively, in comparison to their pristine form. Also, all phosphors along with the PKY159 additive were examined for their decay time kinetics, thermal stabilities, CIE chromaticity coordinates, and quantum efficiencies. The YAG:Ce, NCS:Sm, and CAO:Mn mixes exhibit good thermal stability in addition to internal quantum efficiency (IQE) values that are much higher than the phosphors' additive-free form (95.6%, 66.3%, and 84.6%, respectively). This increase is correlated to an increase in steady-state measurements. These comprehensive analyses contribute valuable insights into the design and optimization of phosphor and coordination polymer blends for improved optical functionality.

A new red phosphor for high time-resolved thermal sensitivity and plant growth.

Luminous materials with a rapid lifetime response have garnered significant interest in sensing technology. In this work, the transition element Mn doped phosphor Sr2TiO4:Mn4+ was synthesized by a traditional high temperature solid phase method. The emission peak of Sr2TiO4:0.009Mn4+ aligns closely with the absorption peak of phytochrome Pfr. The temperature-dependent photoluminescence (PL) spectra and lifetime of Sr2TiO4:0.009Mn4+ were examined within the temperature range of 273-323 K. The temperature sensing characteristics based on the lifetime were analyzed, and the maximum relative sensitivity was 14.93% K-1 at 309 K. The high sensitivity of the Sr2TiO4:0.009Mn4+ phosphor makes it a promising material for temperature sensing applications.

TL, EPR, and optical properties of undoped and Eu-, Ce-, Tb-, Sm-, Cu-, Mn-, and Li- doped MgSiO3 phosphors, synthesized by sol-gel combustion technique

Polycrystalline MgSiO3 samples, undoped or doped with rare earth- (Eu, Tb, Ce, Li, Sm), transition- (Mn and Cu), and alkali metal- (Li) elements, were prepared by the sol-gel combustion method and characterized by thermoluminescence, electron spin resonance, and optical properties. Enstatite and protoenstatite phases are observed in undoped and doped MgSiO3. Better TL results have been observed for phosphors doped with Tb, Ce, and Li (0.5 % mol). Fading experiments and the GCD method have been performed. EPR signals of gamma-irradiated phosphors indicate the formation of radiation-induced defect centers. Cu-doped MgSiO3 shows an unusual feature of the Cu2+ ion. The Cu2+ ion occupies a tetragonally compressed octahedral site, presenting an unconventional attribute. Optical bandgap value Eg is higher for the Ce, Tb, Mn, Li, Sm, and Cu-doped MgSiO3 phosphors. Ce, Li, and Tb dopant ions were found suitable for the MgSiO3 sample regarding its thermoluminescent response and its possible application in radiation dosimetry.

Enhanced red emission of MgAl2O4: Cr3+/Mn4+ phosphor co-doped with alkali metal ions

A series of MgAl2O4: Cr, Mn, M (M = Li, Na, K) red phosphors were prepared by solution combustion combined with subsequently annealing treatment. The influence of Cr3+ or Mn4+ single-doping, Cr3+ and Mn4+ double-doping and alkali metal ions co-doping on the luminescence performance of MgAl2O4 phosphors were systematically investigated. XRD and SEM were used to characterize the composition and morphology of the phosphors, and the optical absorption, photoluminescent excitation, photoluminescent emission, fluorescence lifetime and chromaticity coordinate were performed to characterize their luminescence properties. Compared with Cr3+ or Mn4+ single-doped MgAl2O4 phosphors, Cr3+ and Mn4+ double-doped ones can achieve red light emission under a wide range of excitation from ultraviolet to visible light. Co doping with alkali metal ion Li enhances the fluorescence intensity and lifetime of MgAl2O4: Cr, Mn phosphors.

Tuning Ag+ and Mn2+ doping in ZnS:Ag,Mn embedded polymers for flexible white light emitting films

Flexible Light Emitting Diodes are versatile lighting solutions that offer bendable and adaptable illumination possibilities. A soft, flexible white luminescent film (1 mm) shows promise for foldable electroluminescent devices and applications. This film was fabricated using ZnS:Ag and Mn. Under different excitation wavelengths, the phosphors emit blue light due to Ag+ luminescence centers and red light from the d-d transition of Mn2+. The blue emission is greatly suppressed at high Mn2+ doping levels, requiring reduced Ag+ doping in co-doped ZnS:Ag,Mn compared to solo-doped ZnS:Ag samples. By adjusting Ag+ and Mn2+ concentrations, the ZnS:Ag(1%),Mn(0.2%) phosphors show a proper intensity ratio of blue and red emissions, making them a promising candidate for future white light applications.

Film characteristics of ZnS:Mn phosphor prepared by metal precursor sulfurization and its application to inorganic electroluminescent devices

A ZnS:Mn phosphor film for an inorganic electroluminescent (EL) device fabricated by metal precursor sulfurization was evaluated. Metallic ZnMn was thermally evaporated at room temperature and then sulfurized by sulfur gas flowing in a tube furnace at various temperatures from 400 to 800 °C. X-ray diffraction, energy dispersive x-ray spectroscopy, and photoluminescence observations indicated that a ZnS:Mn phosphor layer was formed after sulfurization. A thick-dielectric EL device was manufactured using the obtained ZnS:Mn phosphor. The EL luminance of 216 cd/m2 at 1.0 kHz was measured when the phosphor layer was sulfurized at 500 °C. A charge density versus voltage (Q-V) curve was also analyzed to evaluate the EL phosphor characteristics.

UV-induced photoluminescence and X-ray-induced thermoluminescence of Zn2SiO4: Mn phosphor

UV-induced photoluminescence and X-ray-induced thermoluminescence of Zn2SiO4: Mn phosphor

High wurtzite content ZnS:Mn with better luminescent performances prepared at lower temperature by a ball milling method

Mechanoluminescent ZnS:Mn phosphor should have a main crystalline structure of wurtzite to get stronger mechanoluminescence. However, preparations of ZnS:Mn with high wurtzite content usually require a high calcination temperature of 1050–1150 °C. Here, we propose an effective strategy of using ball milling premix to greatly reduce the preparation temperature of wurtzite-ZnS:Mn phosphors. X-ray diffraction shows that ZnS:Mn with more than 90 wt% of wurtzite content could be obtained at a calcination temperature of 800 °C, which is 250 °C lower than that without milling. Moreover, the photoluminescence (PL) and mechanoluminescence (ML) of ZnS:Mn phosphors synthesized with a proper milling duration can be considerably enhanced (an enhancement of ∼188% for PL, ∼422% for ML) than those without milling, which maybe correlative with the higher wurtzite content. These findings offer a practical strategy for the large-scale preparation of highly-mechanoluminescent ZnS:Mn and hold the potential to facilitate the development and production of other high-performance phosphors.

Coordination-assembled phosphorescent microstructure from RTP HOF and Eu3+-doping ZGO:Mn phosphors for cancer biomarker amplification detection and information encryption

The ultra-long room temperature phosphorescent hydrogen-bonded organic framework (RTP HOF) materials can achieve long afterglow via ligand hydrogen bond interaction and water implement to suppress the non-radiative decays by matrices rigidification, and its electron donor conjugated structure is first developed as a phosphorescent quencher. The Eu3+/Mn2+ co-doped Zn2GeO4 phosphors (ZGO:Mn, Eu) with abundant metal sites and enhanced phosphorescence were synthesized as response factors and electron acceptors, combined with RTP HOFs to form microstructures featuring multi-color modulation, as an high-level anti-counterfeiting platform and lysophosphatidic acid (LPA) detection unit. LPA is an ideal plasma biomarker for early diagnosis of ovarian and other gynecologic cancers. This detection strategy relies on the differential coordination substitution to restore ZGO:Mn, Eu phosphorescence through synergistic coordination of LPA and the hydrophobic assistance of LPA, and dual functional groups identification of LPA achieve specific detection at the nanomolar level. The anti-counterfeiting platform can fetch specific information by controlling the afterglow distinction and excited light from ZGO:Mn, Eu and RTP HOF. This study not only provides a typical case of the preparation of two phosphors with heterogeneous optical properties, but also expands the application field of combined phosphors as intelligent luminescent materials.

Manganese-doped zinc germanate phosphors with vivid luminescent properties for anti-counterfeit applications

Fluorescent materials are commonly used in optical labels for anti-counterfeiting purposes. However, these well-known materials can be vulnerable to forgery. It is thus essential to develop new types of luminescent materials with unique optical properties. In this paper, we prepared metal-doped phosphor materials with an inorganic matrix using a high temperature solid-state reaction. The synthesized Mn-doped zinc germanate (ZGO:Mn) phosphors were characterized using various techniques, such as X-ray powder diffraction and photoluminescence spectroscopy, in order to understand their structural and optical properties. The ZGO:Mn phosphors exhibit green color fluorescence, persistent luminescence, and photostimulated luminescence (PSL), which are ideal for anti-counterfeiting applications. Several examples of using the PSL active materials on various substrates demonstrate their capability to prevent counterfeiting and forgery. We further showed that an iPhone can be used to reveal the ZGO:Mn-based security labels. This study contributes to the exploration of novel security materials and offers practical implications for the development of security and authentication technologies.

Investigation of dosimetric properties of CaSO4:Mn phosphor prepared using slow evaporation route

The objective of this work was to investigate the luminescent properties of CaSO4:Mn synthesized by slow evaporation route. The crystalline structure, morphology, thermal and optical properties of the phosphors were characterized by X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM), photoluminescence (PL) and thermogravimetric analysis (TGA). Moreover, using thermoluminescence (TL) and optically stimulated luminescence (OSL) techniques, the dosimetric properties of the phosphors, such as emission spectra, glow curve reproducibility, dose-response linearity, fading of the luminescent signal, variation of the TL intensity with the heating rate, OSL decay curves, correlation between TL and OSL emissions and minimum detectable dose (MDD) were comprehensively investigated. For dosimetric analyses, the samples were irradiated with doses from 169 mGy to 10 Gy. The emission band fits with the characteristic line of the Mn2+ emission features, ascribed to 6A1→4T1 transition. CaSO4:Mn pellets present a TL glow curve with a single typical peak centered around 494 nm, an OSL decay curve with predominance of a fast decay component, and a MDD on the order of mGy. The luminescent signals showed to be linear and reproducible in the studied dose range. The trapping centers located between 0.83 eV and 1.07 eV were revealed for different heating rates in the TL study. The high TL sensitivity of CaSO4:Mn was proven when comparing with commercially available dosimeters. The luminescent signals exhibit a smaller fading than described in the literature for CaSO4:Mn produced by other methods.

Self-powered, flexible, and instantly dynamic multi-color electroluminescence device with bi-emissive layers for optical communication

Self-powered alternating current electroluminescence (ACEL) displays own distinctive preponderance in artificial electronic skins and information communication in the internet of things (IoT). However, their limited color options, i.e., monochrome or static multicolor, hinder their versatility. In this paper, we introduce an instantly dynamic multi-color display system that combines integrated bi-emissive layer ACEL with a dual-cells triboelectric nanogenerator (DC-TENG). Our bi-emissive ACEL device includes ZnS:Cu and ZnS:Mn phosphors blended in polydimethylsiloxane (PDMS) to achieve green and orange emissions, respectively. The DC-TENG consists of a polytetrafluoroetylene (PTFE) film and two copper tapes, generating an open-circuit voltage of ∼270 V and a short-circuit current of ∼2.5 μA, which is sufficient to power the bi-emissive layer ACEL device. By pressing the DC-TENG cell, the self-powered display system instantly renders green, orange and warm white emissions, making these dynamic multi-color responses useful as information units in the IoT. The self-powered optical communication system is demonstrated by transmitting the word “CHINA”. Our study may provide a new approach for developing self-powered multi-color display systems and expands their potential applications in information communication for the IoT.

Versatile Ca2LnSbO6:Eu3+/Mn4+ (Ln = La, Y, Gd, and Lu) phosphors for temperature sensing and plant growth LED

AbstractA multifunctional double‐perovskite‐type Ca2LnSbO6 (Ln = La, Y, Gd, and Lu) phosphors with Eu3+ and Mn4+ co‐doped were successfully synthesized and designed to simultaneously apply to temperature sensing and plant growth LED. With temperature varying from 303 to 523 K, the integrated intensity of Mn4+ ions (2Eg → 4A2g) markedly decline swifter comparing to Eu3+ ions (5D0 → 7F2) due to the thermal quenching effect. It implies that Mn4+ is susceptive to the temperature in this work. Eu3+ exhibits high heat resistance, which can be selected as a calibration parameter for the fluorescence intensity ratio temperature sensor. The maximum relative sensitivity (Sr) values of Ca2LnSbO6:1%Eu3+, 0.5%Mn4+ (Ln = La, Y, and Gd) phosphor are estimated as 2.19% K−1 at 443 K, 1.68% K−1 at 503 K, and 1.80% K−1 at 483 K, respectively. They are superior to many recent emerging phosphors. Moreover, upon 365 nm excitation, Ca2LnSbO6:1%Eu, 0.5%Mn (Ln = La, Y, Gd, and Lu) phosphors display a wide red emission peaking at 696, 680, 677, and 684 nm, respectively. They come from the overlapped of 2Eg–4A2g of Mn4+ and 5D0–7F4 transition of Eu3+. Their full widths at half maximum are 34, 35, 35, and 29 nm, respectively. They are all perfectly overlapping the absorption curves of chlorophyll a and chlorophyll b, and their fabricated red phosphor‐converted light‐emitting diode device ulteriorly corroborated the promising applications for plant growth. Markedly, the systematic analysis of their crystal chemistry and site preferentially occupancy is first reported and discussed by the bond valence theory.

Broadband UV-Excitation and Red/Far-Red Emission Materials for Plant Growth: Tunable Spectrum Conversion in Eu3+,Mn4+ Co-doped LaAl0.7Ga0.3O3 Phosphors.

Broadband ultraviolet (UV) excitation and red/far-red emission phosphors can effectively convert solar spectrum to enhance photosynthesis and promote morphogenesis in plants. Based on the above application requirements, Eu3+ single-doped LaAl1-yGayO3 solid solutions and Eu3+,Mn4+ codoped LaAl0.7Ga0.3O3 phosphors were designed and synthesized in this work. The LaAl0.7Ga0.3O3:0.05Eu3+ (LAG:Eu3+) phosphor exhibits a strong charge transfer band (CTB) excitation and characteristic 5D0 → 7F2 transition red emission (619 nm), which is very similar to the luminescence properties of Eu3+-organic ligand compound (EuL3). Rietveld refinement studies further revealed that the cation substitution disturbs the site symmetry. The optimal Eu3+, Mn4+ co-doped LaAl0.7Ga0.3O3 (LAG:Eu,Mn) phosphor possesses a dual-band excitation spectrum in broadband ultraviolet (UVA, UVB) area and a dual-band emission spectrum within red/far-red area. Under the sunlight radiation, the real-time spectrum of luminous laminated glasses fabricated by coating the LAG:Eu,Mn phosphor shows the percentage of radiant intensity in the red/far-red region significantly increases, suggesting that the phosphor can be a promising candidate for solar spectral conversion in plant cultivation. We believe this work provides a new idea for developing novel broadband ultraviolet excitation and red/far-red emission phosphors.

Performance improvement of Sr4Al14O25:Mn4+ red emission phosphor via Na+ doping

The absence of high-efficiency oxide red phosphors restricts the development of WLEDs. In this work, Na+-doped Sr4Al14O25:Mn4+ (SAO-Na,Mn) series oxide red phosphors effectively excited by blue chips were successfully prepared. The theoretical calculation, structure and luminescence properties were systematically analyzed. Theoretical calculations indicate that the Na-Mn codoping system exhibits a more stable structure as doping Mn into octahedron Al1 sites and Al1 and Al2 sites (octahedron) are possibly simultaneously occupied. The calculation results also show that Na+ significantly improves the luminescence intensity and thermal quenching resistance and that the red emission only originates from Mn4+ occupying the octahedron. The PL intensity of SAO-Mn increases and then decreases as the Na+ doping content increases, and 0.5 mol is the optimal value. Compared with the PL intensity of SAO-Mn at 150 ℃, that of SAO-0.5Na,Mn increased by approximately 200 %, and the fitting thermal activation energy was 0.84 eV. The fluorescence lifetime continuously decreases with increasing Na+ content. The pure phase and superior morphology were obtained in the 0.5 mol Na+-doped sample. The WLED devices encapsulated with as-prepared SAO-Na,Mn and YAG:Ce3+ phosphors show a correlated color temperature of 4085 K, a color rendering index of 89, and a luminous efficiency of 137.12 lm/W. The above results indicate that the use of SAO-Na,Mn phosphors is expected in warm WLEDs.

Dual-mode multicolor luminescence anti-counterfeiting based on Mn-doped color-tunable MgGa2O4:Zn2+/Ge4+ phosphors

In this paper, a series of MgGa2-x(Zn/Ge)xO4:0.001Mn (x ​= ​0, 0.05, 0.15, 0.3, 0.5, 1 and 1.2) phosphors were successfully synthesized using high temperature solid-state reaction. Under excitation at 377 ​nm, the sample has two emission peaks at 501 ​nm and 673 ​nm, respectively. In this material, Mn2+ and Mn4+ ions replace tetrahedral site (Mg site) and octahedral site (Ga site), respectively. The green emission at 501 ​nm belongs to the 4T1(G)→6A1(S) transition of Mn2+, and the red emission of 673 ​nm belongs to the 2E →4A2 transition of Mn4+.

Coprecipitation synthesis of Ca14Al10Zn6O35:Mn4+ deep‐red phosphor and silica‐modified waterproofing ability

AbstractCa14Al10Zn6O35:Mn4+ (CAZ:Mn) phosphor material, which shows deep‐red luminescence, was synthesized by the coprecipitation (COP) method using a Na2CO3/NaOH solution as the precipitant. COP–CAZ:Mn phosphor exhibited a 2.1 times higher luminescence intensity than the corresponding phosphor prepared using the conventional solid‐state reaction (SSR) method. This substantial increase in luminescence was mainly ascribed to the existence of a greater proportion of tetravalent manganese in COP–CAZ:Mn phosphor. Furthermore, COP–CAZ:Mn phosphor was modified with SiO2 via hydrolysis of tetraethoxysilane (TEOS) to waterproof the compound because it is easily decomposed through hydrolysis under humid conditions. The SiO2‐modified CAZ:Mn phosphor maintained its crystal structure and high photoluminescence intensity after the water‐resistance test. Therefore, waterproof CAZ:Mn phosphor with a high luminescence intensity was successfully discovered by utilizing the coprecipitation method and SiO2 modification.

Luminescence and photoconversion properties of micro-powder phosphors based on the Ce3+ and Mn2+ doped Ca2YMgScSi3O12 silicate garnets

This work is dedicated to study the synthesis processes and luminescence properties of micro-crystalline powder phosphors of Ce3+ and Mn2+ doped Ca2YMgScSi3O12 garnets (CYMSSG:Ce and CYMSSG:Ce,Mn) The photoluminescence emission spectra and decay kinetics confirm the formation of Ce3+ multicenters in the CYMSSG:Ce powder phosphor due to local inhomogeneity of the different dodecahedral positions and presence of the energy transfer between high-energy and low energy Ce3+ emission centers in this garnet. The effective Ce3+ to Mn2+ energy transfer process is observed in CYMSSG:Ce, Mn phosphors resulting in the redshift of the emission spectra in comparison with CYMSSG:Ce counterpart. We have shown that CYMSSG:Ce and CYMSSG:Ce, Mn powder phosphors can be used as an efficient photoconverter (PC) for creation of the high-power white LEDs (WLEDs). The prototypes of PC-WLEDs, based on 450 nm emitting blue LED and planar layers of CYMSSG:Ce and CYMSSG:Ce, Mn microcrystalline powder phosphors, embedded in the epoxy resin, were prepared and their photoconversion properties were investigated as well.

Solid-state synthesis of the Zn2SiO4:Mn phosphor: Sequence of phase formation, localization and charge state of Mn ions in the intermediate and final reaction products

The phase and structure formation of the Zn2SiO4:Mn phosphor during solid-state synthesis in air from ZnO, SiO2, and Mn2O3 was studied by differential thermal, thermogravimetric, X-ray phase diffraction, and luminescent analyses. It has been shown that the first product of their interaction is a solid solution with the spinel structure (Zn1-хMn2+х)Mn3+2O4 (700°С); with an increase in temperature, ZnMn3+2O4 heterolite is formed. When heated to 900°С, willemite Zn2SiO4 appears along with heterolite. At higher temperature, the interaction of ZnMn3+2O4 with SiO2 leads to the formation of Zn2SiO4:Mn with an impurity of rhodonite Mn2+SiO3. A further increase in temperature activates the interaction of willemite, heterolite, rhodonite, silicon and zinc oxides. At about 1250 °C, this heterophase mixture forms the final single-phase product - the Zn2SiO4:Mn phosphor.

Utilizing a strait-range green phosphor γ-AlON:Mn,Mg for the task of achieving a super-broad hue gamut display

<span><span>The screen backlighting produced by green β-sialon:Eu, as well as red K<sub>2</sub>SiF<sub>6</sub>:Mn phosphors, have an extremely expansive hue gamut that encompasses the majority of the </span></span>national television system committee <span>(NTSC) triangle. For our research, a substitute phosphor in green would be probed in terms of improving the screen hue range even further. The phosphor γ-AlON:Mn,Mg appears to be green in color with a smaller radiation band of colors than sharp β-silaon:Eu. By replacing γ-AlON:Mn,Mg with β-sialon:Eu, the screen hue range in the blue-green area is significantly expanded. In both the CIE 1931 and CIE 1976 hue spaces, the hue range of screens with γ-AlON:Mn,Mg, and K<sub>2</sub>SiF<sub>6</sub>:Mn entirely surpasses the NTSC benchmark. Furthermore, the stability of LEDs emit white light using γ-AlON:Mn,Mg appears to be similar to LEDs that utilize β-sialon:Eu.</span>