Co-doped Phosphors Research Articles

Luminescence and energy transfer of Ce3+, Eu2+ Co-doped SrSi2O2N2 phosphors

SrSi2O2N2:Ce3+/Eu2+ phosphors have been synthesized with a high-temperature solid-state reaction method. The result shows that effective energy transfer has occurred between Ce3+ and Eu2+. The energy transfer efficiency was calculated, and the mechanism was determined as dipole-dipole interaction. The Influence of co-doping with a charge compensator M+ (M+ = Li+, Na+, K+) on the photoluminescence properties of SrSi2O2N2:Ce3+/Eu2+ was analyzed. It is clear that the PL properties of the SrSi2O2N2:Ce3+/Eu2+ phosphor are significantly improved by doping with Li+/Na+/K+, and the Li+ ions is the best charge compensator for this phosphor.

Tunable color and efficient energy transfer of KBaBP2O8:Ce3+, Tb3+ phosphors with low thermal quenching

Using functional phosphors that have a range of benefits, such as quick response to n-UV/blue light excitation, high quantum efficiency and low thermal quenching is crucial. In this work, we have utilized the traditional high-temperature solid-state reaction to synthesized Ce3+, Tb3+ single- and co-doped KBaBP2O8 (KBBPO) phosphors. The phase purity, crystal structure, surface morphology, decay behavior, thermal stability, the luminescence properties and energy transfer process from Ce3+ to Tb3+ were investigated in details. Due to the Ce3+ can adequately sensitize Tb3+, the co-doped phosphors can be effectively excited by near-ultraviolet (NUV) light. The emission color chromaticity for the various KBBPO phosphors varies from dark blue to bright green with the increased concentration of Tb3+. The energy transfer mechanism between Ce3+ and Tb3+ is dominated by the exchange interaction, while the efficiency of the energy transfer is calculated as 59.29%. The optimal KBaBP2O8: 0.02Ce3+, 0.05 Tb3+ phosphor demonstrated low thermal quenching, which only reduces 19.3% of the initial intensity at 150 °C. The new KBaBP2O8: Ce3+, Tb3+ phosphor will be a potential candidate for wide-color-gamut display backlights.

Energy transfer induced colour tunable photoluminescence performance of thermally stable Sm3+/Eu3+ co-doped Ba3MoTiO8 phosphors for white LED applications

Energy transfer induced colour tunable photoluminescence performance of thermally stable Sm3+/Eu3+ co-doped Ba3MoTiO8 phosphors for white LED applications

Synthesis and photoluminescence characterizations of Zn2+ and Tb3+ codoped CeO2 phosphors for temperature sensing applications

Cyan light-emitting Ce0.985-xZnxO2:0.015 Tb3+ (x = 0 to 0.2) phosphors were synthesized using the ethylenediaminetetraacetic acid-assisted hydrothermal method. The X-ray diffraction and refinement analyses of the prepared phosphors indicated that the formed face-centered cubic structure remained intact even after the doping of large quantities of Zn2+ ions. However, the incorporation of Zn2+ ions increased the Ce3+/Ce4+ ratio, resulting in the enhancement of oxygen vacancies in the prepared phosphors. The generation of oxygen vacancies caused the evolution of a broad photoluminescence emission band ranging from 400 to 525 nm with a characteristic Tb3+ emission of approximately 543 nm. Two-emission regions in Ce0.885Zn0.1O2:0.015 Tb3+ phosphors were utilized for measuring the fluorescence intensity ratio (FIR) as a function of temperature ranging from 303 to 523 K. At 523 K, the FIR values dropped to approximately 40% of the starting temperature value. The variation of FIR values followed the Boltzmann behavior. The Boltzmann fitting demonstrated the feasibility of the present phosphors for temperature sensor applications. The optimum absolute sensor sensitivity of Ce0.885Zn0.1O2:0.015 Tb3+ phosphors was measured to be 0.0043 K−1 at 398 K with a resolution of approximately 1 K−1. Moderate temperature sensitivity, negligible hysteresis loop, and excellent reversibility revealed the suitability of Ce0.885Zn0.1O2:0.015 Tb3+ phosphors for sensing the temperature in various electronic devices.

Study on the mechanism of high energy transfer efficiency of blue light excited Cr3+, Nd3+ co-doped near infrared phosphors.

Although Cr3+ as activator for Near infrared (NIR) phosphors has been widely studied, the peaks of Cr3+ emission spectra in most hosts are less than 1000 nm. Nd3+ as an activator in many hosts has a wide distribution of absorption peaks in the Ultraviolet-visible-Near infrared (UV-vis-NIR) band, especially in the 650-900 nm band for effective NIR to NIR Stokes luminescence (4F3/2→4I9/2, 4F3/2→4I11/2 transitions). Therefore, Cr3+, Nd3+ co-doping to achieve the emission in the NIR II region (1000-1700nm) is very meaningful. Here, we report La2CaZrO6(LCZO): Cr3+, Nd3+ NIR phosphors with emission spectra covering an ultra-wide range of 700-1400 nm and reveal their luminescence mechanism. The energy transfer efficiency of Cr3+ for Nd3+ can be as high as 88.4% under 471 nm blue light excitation. In the same case, the integrated intensity of the emission spectra of Cr3+, Nd3+ co-doped can reach 847% of that of Nd3+ alone and 204% of that of Cr3+ alone. Finally, the combination of commercial blue light chips and Cr3+, Nd3+ co-doped NIR phosphors shows great potential for applications in face recognition, night lighting, and angiography.

Luminescence and energy transfer of Ce3+/Tb3+ activated fluoroborate BaGaBO3F2 as a color tunable phosphor

Ce3+/Tb3+ co-doped BaGaBO3F2 is a new rare-earth activated luminescent material with efficient green luminescence. The phosphor was synthesized via the conventional solid-state reaction and characterized by X-ray powder diffraction, photoluminescence, and decay lifetimes. The Ce3+/Tb3+ co-doped phosphor exhibits an efficient excitation between 280 and 420 nm, making it suitable for commercial near-UV chips. The 4f–5d transitions of Ce3+ sensitizer allow the phosphor to be excited by the near-UV light, resulting in green and blue luminescence from Tb3+ and Ce3+, respectively. By controlling Ce3+/Tb3+ doping, the luminescence color can be tuned from blue to green. The effective transfer of excitation energy from Ce3+ to Tb3+ of BaGaBO3F2 was confirmed by the spectral characteristics and decay lifetimes of samples with different doping concentrations. The dipole-quadrupole mechanism is responsible for the efficient energy transfer from Ce3+ to Tb3+, with a critical distance of 11.69 Å. These results demonstrate that Ce3+/Tb3+ co-doped BaGaBO3F2 is an efficient near-ultraviolet (NUV) excitation phosphor with tunable luminescence from blue to green. This material has the potential to be used as a down-conversion phosphor for NUV light-emitting diodes.

Trap engineering in ZnGa2O4:Tb3+ through Bi3+ doping for multi-modal luminescence and advanced anti-counterfeiting strategy

Optical information encryption based on luminescence materials have received much attention recently. However, the single luminescence mode of the luminescence materials greatly limits its anti-counterfeiting application with high safety level. Here, a series of luminescence materials of Tb3+ and Bi3+ co-doped ZnGa2O4 phosphors with great correspondence in photoluminescence (PL), persistent luminescence (PersL), and thermoluminescence (TL) modes was synthesized by the conventional solid-phase method for the application in multi-modal anti-counterfeiting fields. Under the excitation of 254 nm, ZnGa1.99O4:0.01 Tb3+, yBi3+ (y = 0.001,0.002) sample exhibited a broad blue emission band (the transition from [GaO6]) at 440 nm and the characteristic emission peaks of Tb3+ at 495 nm, 550 nm, 591 nm and 625 nm, corresponding to the transitions of 5D4-7Fn (n = 6, 5, 4, 3), respectively. Interestingly, the co-doping of Bi3+ ions improve the crystallinity and particle size of the phosphor, subsequently enhanced the PL intensity of Tb3+ to 6 times that of Tb3+ singly doped ZnGa2O4 phosphor. Further, the flexible films with multi-modal luminescence properties have been fabricated through the unique TL and PersL characteristics of ZnGa2O4: Tb3+, Bi3+ phosphors, including “Optical information storage film”, “snowflake and characters” and “QR code”. Moreover, a set of optical information encryption is obtained by combining ZnGa2O4:Tb3+, Bi3+ phosphor and red emitting phosphor. The results indicate that ZnGa2O4:Tb3+, Bi3+ phosphor with multi-modal stimulus response can be expected to be potentially used in the applications of optical information storage and anti-counterfeiting fields.

Luminescence properties of Tb3+/Eu3+ ions activated LiLaSiO4 phosphors for solid-state lighting and flexible display applications

The synthesis and luminescence properties of Tb3+ and Eu3+ single- and co-doped LiLaSiO4 (LLSO) phosphors with energy transfer mechanisms were reported. The rare-earth ions doped LLSO phosphors were synthesized via a solid-state reaction method and their physical characterizations such as phase purity, surface morphology, and elemental analysis were investigated systematically. For the Tb3+ and Eu3+ single- and co-doped LLSO phosphors, their photoluminescence (PL) properties were studied in detail. The LLSO:Tb3+ and LLSO:Eu3+ single-doped phosphors showed superior red and green emissions due to 5D4→7F5 and 5D0→7F2 in the optimized characteristic electronic transitions under ultraviolet (UV) irradiation, respectively. The luminescence performances for both the LLSO:Tb3+ and LLSO:Eu3+ phosphors were optimized at 0.125 mol of doping ion concentration. Under UV excitation, by adjusting the Eu3+ ion concentration in LLSO:0.125Tb3+/Eu3+ phosphors, the tunable emissions from green to red via yellow-orange were obtained. Thus, the tunable emission spectra and luminescence decay lifetimes with increasing the doping content of acceptor ions (Eu3+) confirmed an efficient energy transfer from Tb3+ to Eu3+ ions in the co-doped samples. The critical distance between Tb3+ and Eu3+ was determined to be 13.26 Å and the energy transfer mechanism from Tb3+ to Eu3+ ions was demonstrated to be a dipole-dipole mechanism interaction. In addition, the temperature-dependent PL study was carried out for the LLSO:0.125Tb3+/0.025Eu3+ co-doped phosphor sample and it showed better thermal stability against the temperature quenching. The Tb3+ and Eu3+ single- and co-doped LLSO/polydimethylsiloxane (PDMS) flexible composite films were fabricated by mixing the phosphor powders and PDMS solution. Benefiting from the effective protection of the PDMS matrix, the luminescence stability of the composite films was greatly enhanced. Based on the excellent properties of the synthesized phosphors, Tb3+ and Eu3+ single-doped and Tb3+/Eu3+ co-doped LLSO phosphors could serve as a single-phase multicolor-emitting phosphor under UV excitations.

Optical transition and near-infrared upconversion luminescence properties of YNbO4: Er3+, Yb3+ phosphors

Optical transition and near-infrared upconversion luminescence properties of Er3+ single-doped and Er3+, Yb3+ co-doped YNbO4 phosphors are reported. Based on the framework of Judd-Ofelt theory and modified Judd-Ofelt calculation method, the optical transition properties of Er3+ and Yb3+ ions in YNbO4: Er3+, Yb3+ sample were studied, respectively. The calculated results showed that the absorption cross-section of Er3+ ion at ∼1550 nm is larger than that at ∼980 nm in YNbO4: Er3+ phosphor. And, the absorption cross-section of 2F7/2 → 2F5/2 transition of Yb3+ in YNbO4: 15.0 mol% Er3+, 15.0 mol% Yb3+ sample was calculated to be 138.70 × 10−20 cm2. According to the emission cross section of Er3+ (4I11/2 → 4I15/2) and the absorption cross section of Yb3+ (2F7/2 → 2F5/2), the energy transfer rates from Er3+ to Yb3+ were quantitatively analyzed via the Föster-Dexter model. Furthermore, 1550 nm was selected as the excitation wavelength, the near-infrared upconversion emission spectra of YNbO4: Er3+, Yb3+ samples were measured. It was found that the sample has strong emission at ∼980 nm and the emission intensity was still enhanced with the incorporation of Yb3+.

Synthesis and spectroscopic characterization of Ce0.90Eu0.07Sm0.03O2 phosphors for luminescence-based thermometry applications

Uniform nanoparticles of Eu3+/Sm3+ co-doped CeO2 phosphors were prepared through a hydrothermal method assisted with ethylenediaminetetraacetic acid (EDTA) as a chelating agent. The pH values of the precursor solution were varied to obtain uniform morphology of Eu3+/Sm3+ co-doped CeO2 phosphors and the most uniform morphology of Eu3+/Sm3+ co-doped CeO2 phosphors was obtained at pH 10. The maximum photoluminescence efficiency was observed at 7 mol% of Eu3+ and 3 mol% of Sm3+ ions of Eu3+/Sm3+ co-doped CeO2 phosphors. The emission spectra for Ce0.9Eu0.07Sm0.03O2-δ phosphors consisted of a host (450–560 nm) and dopant (570–700 nm) emissions. The ratio between the intensity of host and dopant emissions showed strong temperature dependence and the variation of intensity ratio was utilized for temperature sensing. Within the studied temperature range (298–523 K), the value of absolute sensor sensitivity for Ce0.9Eu0.07Sm0.03O2-δ phosphors was elevated from 0.0026 to 0.025 K−1. The maximum relative sensor sensitivity of Ce0.9Eu0.07Sm0.03O2-δ phosphors was 2.8% K−1 at 373 K. The high sensor sensitivity and uniform morphology of Ce0.9Eu0.07Sm0.03O2-δ phosphors could be used for luminescence-based thermometry applications.

The Broadband Emitting and Lattice Occupation Analysis of Eu2+, Eu3+ and Ce3+ co-doped K3YSi2O7 Phosphors

Eu3+, Eu2+ and Ce3+ doped K3YSi2O7 phosphors are synthesized under reducing atmosphere. Photoluminescence properties show K3YSi2O7:1%Ce, 1%Eu at 330 nm excitation (FWHM = 211 nm, where FWHM stands for the full width at half maximum) can produce broadband emission. The preferential occupation sites of Ce and Eu ions in K3YSi2O7 are calculated using the bond energy theory. Eu2+, Eu3+, Ce3+ ions preferentially occupy K3, Y2, K1 sites, respectively. The broadband emission of the phosphor is caused by the dopant ions’ selective site occupancy.

The Upconversion Luminescence of Ca3Sc2Si3O12:Yb3+,Er3+ and Its Application in Thermometry.

To develop novel luminescent materials for optical temperature measurement, a series of Yb3+- and Er3+-doped Ca3Sc2Si3O12 (CSS) upconversion (UC) phosphors were synthesized by the sol-gel combustion method. The crystal structure, phase purity, and element distribution of the samples were characterized by powder X-ray diffraction and a transmission electron microscope (TEM). The detailed study of the photoluminescence emission spectra of the samples shows that the addition of Yb3+ can greatly enhance the emission of Er3+ by effective energy transfer. The prepared Yb3+ and Er3+ co-doped CSS phosphors exhibit green emission bands near 522 and 555 nm and red emission bands near 658 nm, which correspond to the 2H11/2→4I15/2, 4S3/2→4I15/2, and 4F9/2→4I15/2 transitions of Er3+, respectively. The temperature-dependent behavior of the CSS:0.2Yb3+,0.02Er3+ sample was carefully studied by the fluorescence intensity ratio (FIR) technique. The results indicate the excellent sensitivity of the sample, with a maximum absolute sensitivity of 0.67% K-1 at 500 K and a relative sensitivity of 1.34% K-1 at 300 K. We demonstrate here that the temperature measurement performance of FIR technology using the CSS:Yb3+,Er3+ phosphor is not inferior to that of infrared thermal imaging thermometers. Therefore, CSS:Yb3+,Er3+ phosphors have great potential applications in the field of optical thermometry.

Photoluminescence and Temperature Sensing Properties of Bi3+/Sm3+ Co-Doped La2MgSnO6 Phosphor for Optical Thermometer

The optical temperature sensor utilizing the fluorescence intensity ratio (FIR) has garnered significant attention in the past few years due to its rapid response, robust anti-interference capability, remote control feature, and other advantages. In this study, the high-temperature solid-phase approach was used to fabricate a variety of double perovskite-structured La2MgSnO6: Bi3+, Sm3+ (LMS: Bi3+, Sm3+) phosphors. The Rietveld refinement data of XRD and the Gaussian fitting of the emission peak of LMS: 0.02Bi3+ phosphor indicated Bi3+ occupies three lattice sites. The calculation and analysis of average lifetime and energy transfer efficiency substantiated the presence of energy transfer from Bi3+ to Sm3+, with a transfer efficiency of up to 59.07%. The emission intensity of LMS: 0.02Bi3+, 0.05Sm3+ at 403 K maintains 50.2% at the condition of room temperature. The FIR fitting and calculation demonstrated that LMS: 0.02Bi3+, 0.05Sm3+ phosphor possessed good optical temperature sensitivity, with a maximum absolute sensitivity Sa-max of 0.0055 K−1 and a maximum relative sensitivity Sr-max of 0.88% K−1, demonstrating its valuable potential applications for optical temperature sensors.

Design strategies for three highly sensitive multimodal optical thermometers based on diverse luminescence thermal-response in BaLu2Si3O10:Ln3+, Yb3+ phosphors (Ln3+=Er3+, Ho3+, Nd3+)

Optical thermometer has gradually become a hotspot due to its contactless measurement, high spatial resolution and rapid response, while most of them currently used single-mode measurement without reference and calibration. Herein, three multimodal optical thermometers were designed in BaLu2Si3O10: Er3+/Ho3+/Nd3+, Yb3+ phosphors. Interestingly, both Er3+ and Ho3+ doped phosphors demonstrated thermochromic phenomenon, promising to be candidates for intelligent high-temperature alarms. Benefiting from diverse thermo-response of green and red emissions of above two phosphors, two visible two-mode optical thermometers were established by four fluorescence intensity ratio (FIR) modes. Besides, a near-infrared (NIR) multimodal optical thermometer was also proposed by three FIR modes in Nd3+-Yb3+ co-doped phosphor with continuous luminescence thermal enhancement. Because of efficient phonon-assistance energy transfer process, the 4F7/2 → 4I9/2 transition demonstrated super thermal enhancement over 2600 times. The method by integrating several independent optical addressed temperature readout modes provides diversified avenue toward the design of highly sensitive optical thermometers.

An optical fiber temperature sensor based on fluorescence intensity ratio in Er3+/Yb3+ co-doped Gd2O3 phosphors

A simple optical fiber temperature sensing system based on up-conversion luminescence of Er3+/Yb3+ co-doped Gd2O3 phosphors is proposed and demonstrated for the first time. The Gd2O3: 1 mol% Er3+, 1 mol% Yb3+ phosphors are synthesized by traditional sol-gel method. A sandwich structure fabricated by two fiber connectors, one of which is deposited the fluorescent material cured with ultraviolet adhesive on the surface, is used as the sensing probe. Temperature measurement is achieved using the two green emissions, generated by Gd2O3: 1 mol% Er3+, 1 mol% Yb3+ phosphors, based on the fluorescence intensity ratio (FIR) technique. When the Gd2O3: 1 mol% Er3+, 1 mol% Yb3+ phosphor is excited by the 980 nm laser with the output power of 73 mW, the intense green emissions are observed and change with temperature. The temperature sensing characteristics are experimentally studied in the temperature range from 253 to 413 K, with the maximum absolute sensitivity of 4.15% K−1 at 413 K, the maximum relative sensitivity of 2.28% K−1 at 253 K and the maximum relative error of 0.43%. The proposed optical fiber temperature sensor not only offers excellent reversibility and stability, but also significantly contributes to accurate and remote temperature measurement in harsh environments.

Upconversion 3D printing enhancement via silver sensitization to enable selective metallization

This work presents the synergistic effect of silver (Ag) ions to enhance the crosslinking of 3D printing photopolymers via near-infrared (NIR) to ultraviolet (UV)/visible light upconversion (UC) and allow selective metallization of multi-material parts. By incorporating a commercial micron-sized ytterbium-thulium co-doped sodium yttrium fluoride phosphor (NaYF4:Yb3+, Tm3+) into a photopolymer resin, a low-cost NIR laser is used to initiate curing exactly at the focal point in the depth of the vat, allowing voxel crosslinking in any point of the space at a depth in the centimeter scale, beyond the traditional layer-by-layer 2D scheme. This allows the printing with the presented resin on pre-existing printed parts, which is the basis for multi-material integration in 3D printing, beyond the 2D limitation. The addition of Ag(I) ions in the photopolymer enables improved photo-curing at 10-fold faster speeds, after printing through 10 mm of resin. In our approach, after the 3D printing process, the Ag(I) ions embedded into the photopolymer serve as seeding sites for electroless copper (Cu) plating, which allows the integration of metalized parts on different substrates, such as glass and 3D printed polymer. Finally, selective copper plating has enabled the manufacture of objects with metal (copper) and plastic (acrylic) surfaces.

Tunable white light photoluminescence of a single phase Tm3+/Tb3+/Eu3+ codoped GdPO4 phosphor

The present study describes the production of triply-doped GdPO4 and its optical characteristics. Structural information of the prepared material has been investigated by using X-ray diffraction and Fourier transform infrared spectroscopy. The material synthesized crystallizes into a single monoclinic crystal of space group P 21/n. The excitation curves of photoluminescence of single doped GdPO4: Tm3+, Tb3+, and Eu3+ are recorded and their emission spectra are analyzed. Triple-doped material emits multi colour light after a single UV stimulation. White light emission was seen in both triply-doped GdPO4 with variable Tm3+ concentration and triply-doped GdPO4 with variable Eu3+ concentration. GdPO4 doped with Tb3+ (7 mol%), Tm3+ (1.5 mol%), and Eu3+ (2 mol%) has colour coordinates (x = 0.3290, y = 0.3291) approximately near the value of typical white colour coordinates (x = 0.333, y = 0.3333). Furthermore, the transfer of energy in Tm3+, Tb3+ and Eu3+ in triple doped phosphor with varying Eu3+ concentrations was explained. Electric dipole-dipole interaction is used to justify and describe the process of energy transfer from Tb3+ to Eu3+. Decay time measurements were performed to explain energy transfer. Colour rendering index (CRI), Corelated colour temperature (CCT), Quantum efficiency and thermal stability of the prepared phosphor was calculated. All these parameters infer that GdPO4 doped with Tm3+, Tb3+ and Eu3+ may have potential application in white LEDs.

Temperature-dependent vacuum ultraviolet photoluminescence spectroscopy of transition metal and rare earth co-doped ZnO phosphors: a synchrotron-based investigation

Temperature-dependent vacuum ultraviolet photoluminescence spectroscopy of transition metal and rare earth co-doped ZnO phosphors: a synchrotron-based investigation

Electrospun green-emitting La2O2CO3:Tb3+ nanofibers and La2O2CO3:Tb3+/Eu3+ nanofibers with white-light emission and color-tuned photoluminescence

Color-tuned luminescence and white-light emission materials have attracted much attention owing to their broad application prospects. Generally, Tb3+ and Eu3+ co-doped phosphors have color-tuned luminescence, but white-light emission is rarely achieved. In this work, color-tunable photoluminescence and white light emission are achieved in Tb3+ and Tb3+/Eu3+ doped monoclinic-phase La2O2CO3 one-dimensional (1D) nanofibers synthesized by electrospinning united with succedent strictly controlling calcination procedure. The prepared samples own excellent fibrous morphology. La2O2CO3:Tb3+ nanofibers are the superior green-emitting phosphors. To obtain 1D nanomaterials with color-tunable fluorescence, particularly those with white-light emission, Eu3+ ions are further selected and doped into La2O2CO3:Tb3+ nanofibers to obtain La2O2CO3:Tb3+/Eu3+ 1D nanofibers. The major emission peaks of La2O2CO3:Tb3+/Eu3+ nanofibers at 487, 543, 596 and 616 nm are attributed to 5D4→7F6 (Tb3+), 5D4→7F5 (Tb3+), 5D0→7F1 (Eu3+) and 5D0→7F2 (Eu3+) energy levels transitions under 250-nm (for Tb3+ doping) and 274-nm (for Eu3+ doping) UV light excitation, respectively. At different wavelengths excitation, La2O2CO3:Tb3+/Eu3+ nanofibers with excellent stability achieve color-tuned fluorescence and white-light emission with the help of energy transfer from Tb3+ to Eu3+ and tuning the doping concentration of Eu3+ ions. Formative mechanism and fabrication technique of La2O2CO3:Tb3+/Eu3+ nanofibers are advanced. The design concept and manufacturing technique developed in this work may offer fresh insights for synthesizing other 1D nanofibers doped with rare earth ions to tune emitting fluorescent colors.

Tuning green-to-red ratio of Ho3+ Activated YPO4 dual-mode luminescence through Yb3+ sensitized nano phosphors

INTRODUCTION: Yb3+/Ho3+co-doped YPO4 nano phosphors were synthesized by polyol route, which has both up-conversion (UC) and down-conversion (DC) characteristics and excellent luminescent properties. DC peaks were seen at ~460, ~550, and ~650 nm. METHOD: Switching at ~750 with 300 nm excitation, a very faint P-O charge-transfer (CT) band of the Ho3+ ion and a minute non-radiative resonant energy transfer were observed. We found that YPO4: Yb3+/Ho3+ is an up-converting (UC ) nano phosphor capable of large-scale generation and enhancement of luminescence with green and red emissions.RESULT: Under strong laser irradiation at 980 nm, the up-conversion emission spectrum shows obvious peaks expected for Ho3+ ions at ~550 and ~650 nm. This process produces high-quality nanocrystalline materials with sizes in the range of tens of nm. Considering the results obtained under excitation at 300nm, YPO4:Yb3+/Ho3+ yielded high quantum yield values CONCLUSION: This finding can be used to manufacture high-efficiency phosphors and demonstrates that the nano-phosphor materials covered by this method have a wide range of applications.