ZnGa2O4 Phosphor Research Articles

Beta-irradiated ZnGa2O4:Sm3+ phosphor: Thermoluminescence glow curves and kinetic parameters via gel combustion synthesis

This study examines the X-ray Diffraction (XRD) characteristics of Sm3+-doped ZnGa2O4 phosphor, shedding light on its structural characteristics. The XRD data reveal distinctive peaks that represent the crystal's lattice structure. This provides the basis for a more detailed analysis of thermoluminescence (TL). Initially, the TL glow curves corresponding to different concentrations of Sm were analysed, leading to the identification of the most favorable Sm concentration. Subsequently, an investigation was conducted into the TL behavior of the material in response to varying doses within a broad spectrum of beta radiation, revealing a linear characteristic (b=1.075) across doses ranging from 0.1 Gy to 50 Gy. Following this, a reusability assessment was executed over three measurement sets, wherein it was ascertained that the deviation in peak area across ten cycles did not surpass 2 %. Furthermore, it was investigated how different heating rates ranging from 0.5 °C/s to 7 °C/s affect the TL curve of the material. To determine the TL trap parameters of the sample, Initial Rise (IR) and Computerized Glow Curve Deconvolution (CGCD) methods were employed. A consistent pattern of activation energy values was observed in both IR in the TM-Tstop experiment and CGCD analyses, indicating a uniform response to distinct energy levels within the sample. In terms of providing valuable insights into the characteristics of TL, these methods were found to be very effective. This contributed to a comprehensive understanding of charge carrier dynamics within the crystal lattice. Moreover, Peaks I, II, and III showed a linear response to applied doses, indicating the material's potential for dosimetry applications. The findings of this study not only provide insights into Sm3+-doped ZnGd2O4 phosphors' TL properties, but also enhance our understanding of how to optimize their radiation response.

Cation Occupation Engineering Realizes Valence Modulation of Manganese-Activated ZnGa2O4.

Herein, a series of Mn-activated ZnGa2O4 (ZGO) phosphors have been developed for multifunctional applications. The characteristic green and red emission at 503 and 668 nm of Mn-activated ZGO phosphors can be observed under excitation of 247 and 375 nm, respectively, attributed to the partial oxidation of Mn2+ ions resulting in the coexistence of Mn2+ and Mn4+ ions in the host lattice. The valence modulation of Mn content not only realizes the adjustment of red and green luminescence intensity but also achieves the management of persistent luminescence time and thermo-luminescence time. Further, the codoping of Mg2+ could transform the position occupancy preference of Mn and effectively facilitate the conversion of Mn2+ to Mn4+, leading to the regulation of the valence state of manganese ions. Surprisingly, the existence of Mg2+ ions broadens the emission band of Mn4+ and enhances the photoluminescence intensity to 3.8 times, which can be ascribed to the weakened crystal field leading to the downward shift of the 4T2 energy level and the increase of Mn4+ concentration. For this valence modulation behavior, two different hypotheses about the occupancy of Mg2+ have been proposed to explain the corresponding phenomenon. Finally, the potential applications of the synthesized phosphors have been explored in advanced anticounterfeiting strategies, information storage, and plant lighting field.

Effect of Li+ monovalent ion on the structural and optical properties of Dy3+ doped ZnGa2O4 phosphor

Effect of Li+ monovalent ion on the structural and optical properties of Dy3+ doped ZnGa2O4 phosphor

Thermoluminescence kinetics in beta-irradiated novel ZnGa2O4:Eu3+ phosphor produced via gel combustion synthesis

Eu3+ doped ZnGa2O4 phosphors with varying dopant concentrations were successfully synthesized using the combustion technique. X-ray diffraction analysis confirmed the consistency of both undoped and Eu3+ doped ZnGa2O4 samples with PDF#38–1240 card structure. The investigation of thermoluminescence (TL) characteristics involved studying TL glow curves in Eu3+ doped ZnGa2O4 samples with different dopant concentrations, employing various optical detection filter combinations. Among these, ZnGa2O4: 2%Eu3+ and the IRSL-TL wide blue band (wbb) proved to be the optimal sample and ideal detection filter pairing for identifying TL features. Following preheating experiments, the TL maximum was observed at around 190 °C, with a heating rate of 2 °Cs−1. The dose-response experiment for ZnGa2O4:2%Eu3+ exhibited satisfactory linearity, with a coefficient of b = 0.988 and an R2 value of 0.989 for doses up to 100 Gy. Moreover, for the dose range of 200–500 Gy, a sublinear relationship was maintained, with a coefficient of b = 0.31 and an R2 value of 0.988. Hoogenstraaten's method, along with the initial rise method and the Tm-Tstop experiment, was also employed in conjunction with a glow curve fitting package. This comprehensive approach facilitated the determination of the number of peaks, trap structure, and kinetic parameters within the thermoluminescence glow curve. Glow curve deconvolution using specialized software revealed the presence of five well-isolated and overlapping TL glow peaks, achieving a figure of merit (FOM) value of 1.39.

Hydrothermal synthesis of ZnGa2O4 nanophosphors with high internal quantum efficiency for near-infrared pc-LEDs.

NIR luminescent materials have garnered widespread attention because of their exceptional properties, with high tissue penetration, low absorption and high signal-to-noise ratio in the field of optical imaging. However, producing nanophosphors with high quantum yields of emitting infrared light with wavelengths above 1000 nm remains a significant challenge. Here, we prepared a nanoscale ZnGa2O4:xCr3+,yNi2+ phosphor with good luminescence performance in near-infrared emission, which was synthesized via a hydrothermal method and subsequent calcination process. By co-doping with Cr3+ and Ni2+, the ZnGa2O4 phosphor shows a strong broadband emission of 1100-1600 nm in the second near-infrared (NIR-II) region, owing to the energy transfer from Cr3+ to Ni2+ with an efficiency up to 90%. Meanwhile, a near-infrared phosphor-conversion LED (NIR pc-LED) device is fabricated based on the ZnGa2O4:0.8%Cr3+,0.4%Ni2+ nanophosphor, which has under 100 mA input current, an output power of 23.99 mW, and a photoelectric conversion efficiency of 7.53%, and can be effectively applied in imaging and non-destructive testing. Additionally, the intensity ratio of INi/ICr of ZnGa2O4:0.8% Cr3+,0.4%Ni2+ with its high sensitivity value of 4.21% K-1 at 453 K under 410 nm excitation, indicates its potential for thermometry application.

Host-sensitized colour-tunable emission and Judd-ofelt analysis for Dy3+-doped ZnGa2O4 phosphor through exciton-mediated energy transfer

Single-phase Dy3+-doped zinc gallate (ZnGa2O4) phosphors were synthesized using a conventional solid-state fabrication technique. The structural properties of the host phosphor were determined through X-ray powder diffraction (XRPD) and Rietveld refinement, revealing a cubic spinal structure with a space group of Fd3m. The reflectance properties of the host and doped samples were measured using UV–Vis spectroscopy. The obtained data were used to estimate the bandgap of all the synthesized samples, ranging from 4.18 to 3.69 eV, confirming the formation of a wide bandgap semiconductor. Morphological, compositional, and surface mapping analyses were conducted using a field emission scanning electron microscope, energy dispersive electron spectroscopy, and time-of-flight secondary ion mass spectroscopy. X-ray photoelectron spectroscopy was employed to confirm the oxidation state of the constituent elements and for an in-depth study of the crystal structure. Photoluminescence excitation and emission spectra were recorded to analyze the luminescent properties of the synthesized phosphors. It was confirmed that when using an excitation wavelength of 247 nm, all samples exhibited broad host emission with decreasing intensity. In contrast, Dy3+ emission displayed an increasing trend, confirming host sensitization in this phosphor. To analyze the radiative properties of the activator ion, theoretical analysis using the Judd-Ofelt theory was carried out. The results revealed an overlapping of orbitals between the O2− ion and Dy3+, indicating its higher-order covalent nature and the increased symmetric nature of the activator ion in the present host. This characteristic allowed for the generation of near-white light emissions. A concentration of 7 mol% of Dy3+ was observed to match well with achromatic white (0.32, 0.33) on the color chromaticity diagram. The luminous properties of this material suggest that it is a desirable candidate for use in LEDs and AC electroluminescent systems.

Color tunability and NIR luminescence in Cr3+/Li+ co-doped ZnGa2O4 phosphor for solid state lighting and NIR LEDs

In this work, we report the color tunable photoluminescence in the Cr3+/Li+ doped and co-doped ZnGa2O4 (ZGO) phosphors synthesized by solid state reaction method. The phase and surface morphology of ZGO phosphor were examined by XRD and SEM measurements, respectively. The EDS spectra revealed the presence of Zn, Ga, Cr and O elements in the phosphor. The vibrational structure of the phosphor materials has been analyzed by FTIR measurements. The Cr3+ doped phosphor shows electronic absorption bands at 302, 408 and 544 nm alongwith the host CTB at 260 nm. The optical band gap of the phosphor decreases via doping of Cr3+ and Cr3+/Li+ ions. The ZGO is a self-activated host and emits broad blue emission with maximum at 434 nm upon excitation at 260 nm. The Cr3+ doped phosphors show emission bands due to spin-allowed as well as spin-forbidden transitions due to Cr3+ ion in the blue, green and NIR regions on excitation with 260, 302, 408 and 544 nm wavelengths. The emission intensity is optimum for 0.5 mol% concentration of Cr3+ ion. The emission intensity of Cr3+ doped ZGO phosphor increases via doping of Li+ ion. The color tunability has been observed in the phosphor upon 260 and 302 nm excitations. The lifetimes of 4T2 (4F) and 2E states of Cr3+ ion have been measured and it is found that it decreases with increasing concentrations of Cr3+ and Cr3+/Li+ ions. The Cr3+/Li+ doped and co-doped ZGO phosphors may be suitable candidates for display devices, solid state lighting and NIR LEDs.

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.

Wide colour tunability through cross relaxation and energy transfer in a Eu3+/Tb3+:ZnGa2O4 phosphor

In this article, the Tb3+, Eu3+ activated/co-activated ZnGa2O4 phosphors were synthesized using solid state reaction method to study the structural and optical characteristics. The XRD and SEM techniques, were used to study the crystallinity, phase purity and particles size whereas the EDS measurement approved the existence of different elements present in the phosphor samples. The FTIR and diffuse reflectance spectra of phosphor samples were studied to know the phonon frequency and the optical band gap. The PLem spectra of Tb3+ activated ZnGa2O4 phosphor contain blue, green and orange red emissions on 378 nm excitation. A colour tunability from blue to green regions was seen to arise due to cross relaxation on increasing the concentrations of Tb3+ ion. The Eu3+ activated ZnGa2O4 phosphor exhibited a strong red emission under 393 nm excitation. Further, the Eu3+ activated ZnGa2O4:Tb3+ phosphor showed colour tunability from blue to bluish white and from green to red under 260 and 378 nm excitations, respectively. Moreover, an energy-transfer (ET) has been observed from Tb3+ to Eu3+ ions with energy transfer mechanism as dipole-dipole interaction. The ET efficiency for 0.8 mol% Eu3+ in ZnGa2O4:0.05 Tb3+ phosphor has been found 97%. Under 260 nm excitation, the Eu3+/Tb3+ co-activated ZnGa2O4 phosphor also emits blue, green and red bands. Thus, the Tb3+, Eu3+ co-activated ZnGa2O4 phosphor may be useful for solid-state lighting applications.

Thermoluminescence kinetic parameters of beta irradiated the zinc gallate phosphor using different methods

The ZnGa2O4 phosphor material was synthesised through the gel combustion method, and its structural characteristics were studied via X-ray powder diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDX). The XRD result indicates the generation of ZnGa2O4 in spinal cubic phase with a 25 nm crystalline size. The synthesized phosphor was irradiated using a90Sr/90Y source with a dose range of 0.1 Gy–100 Gy. For measuring thermoluminescence (TL), a linear heating rate of 2 °Cs−1 was applied to the sample in a temperature range of 25 °C–450 °C. The TL experiment revealed two peak maxima located at 180 °C and 304 °C and a shoulder around 70 °C. By preheating at 110 °C, the low temperature peak at 70 °C is removed. Both the depth and frequency factors of electron traps were determined using various heating rates (VHR), Tm-Tstop combined with initial rise (IR), and Computerised Glow Curve Deconvolution (CGCD). In both the Tm-Tstop and CGCD methods, six overlapping glow peaks were detected below the main glow peaks. The calculated activation energy values and peak maximum temperatures agree well with each other. The depths of electron traps calculated by different methods were found to be between 0.4 and 1.4 eV. We observed that both peak maximum temperatures and the area under glow peaks gradually decreased with an increase in the heating rate. Both Peak 1 and Peak 2 show sublinear relationship between 0.1-5Gy and 10–100 Gy. The findings of the present study show that the phosphors can serve as effective TLDs.

Multicolor tunable bright photoluminescence in Ca2+/Mg2+ modified Eu3+ doped ZnGa2O4 phosphors under UV excitation for solid state lighting applications.

The Eu3+ doped and Mg2+/Ca2+ co-doped ZnGa2O4 phosphor samples were synthesized by solid-state reaction method and their structural and optical properties studied. The phase, crystallinity and particles size of the phosphor samples were studied by XRD and SEM measurements. EDS analyses were used to identify the elements present in the phosphor materials. The vibrational groups present in the phosphor samples were examined by Fourier transform infrared (FTIR) measurements. Pure ZnGa2O4 emits intense blue light under 260 nm excitation. However, Eu3+ doped and Mg2+/Ca2+ co-doped ZnGa2O4 phosphor samples exhibit intense red emission under 393 nm excitation. A bluish white color is observed in these samples under 290 nm excitation. The maximum PL emission intensity is found at 0.1 mol% Eu3+ doping concentration. For higher concentrations, concentration quenching was observed due to dipole-dipole interaction. The emission intensity is enhanced upto 1.20 and 2.91 times on co-doping of Mg2+ and Ca2+via induced crystal field due to charge imbalance. The emission intensity of the phosphor is found to enhance further on annealing the samples at 873 K. Under various excitation wavelengths, color tunability was seen from blue to bluish-white to red regions. The lifetime of the 5D0 level of the Eu3+ ion improves via doping of Mg2+/Ca2+ ions and it increases appreciably on annealing. The temperature dependent photoluminescence study (TDPL) reveals a thermal quenching behavior of the sample with thermal stability ∼65% and activation energy ∼0.223 eV in the Eu3+/Ca2+ co-doped ZnGa2O4 phosphor sample.

Environmentally-friendly and low-cost Fe3+-doped broadband NIR light-emitting phosphors

Near infrared (NIR) light emitting phosphors have attracted more and more attention with the development of science and technology. Herein, we report a series of environmentally-friendly low-cost Fe3+-activated ZnGa2O4 phosphors which exhibit intense broadband NIR light emitting. According to density functional theory (DFT) calculations, ZnGa2O4 host possesses an indirect wide bandgap. The emission of the Fe3+-doped phosphors demonstrates a wide band spanning from 650 to 850 nm, with the maximum at 720 nm and a full width at half maxima (FWHM) of 70 nm, showing a large overlap with the absorption of phytochromes (PR and PFR). The luminescence intensity remains at 71% when the temperature is raised to 423 K. The phosphors are fabricated into light emitting diodes (LEDs) which produces strong NIR emission with CIE color coordinates of (0.65, 0.31). All these results suggest that ZnGa2O4:Fe3+ is a promising NIR luminescent material, which is expected to be a candidate for indoor plant culture LEDs.

NIR light guided enhanced photoluminescence and temperature sensing in Ho3+/Yb3+/Bi3+ co-doped ZnGa2O4 phosphor

The conversion of NIR light into visible light has been studied in Ho3+/Yb3+/Bi3+ co-doped ZnGa2O4 phosphor for the first time. The crystallinity and particles size of the phosphor increase through Bi3+ doping. The absorption characteristics of Ho3+, Yb3+ and Bi3+ ions are identified by the UV–vis-NIR measurements. The Ho3+ doped phosphor produces intense green upconversion (UC) emission under 980 nm excitations. The emission intensity ~ excitation power density plots show contribution of two photons for the UC emissions. The UC intensity of green emission is weak in the Ho3+ doped phosphor, which enhances upto 128 and 228 times through co-doping of Yb3+ and Yb3+/Bi3+ ions, respectively. The relative and absolute temperature sensing sensitivities of Ho3+/Yb3+/5Bi3+ co-doped ZnGa2O4 phosphor are calculated to be 13.6 × 10−4 and 14.3 × 10−4 K−1, respectively. The variation in concentration of Bi3+ ion and power density produces excellent color tunability from green to red via yellow regions. The CCT also varies with concentration of Bi3+ ion and power density from cool to warm light. The color purity of phosphor is achieved to 98.6% through Bi3+ doping. Therefore, the Ho3+/Yb3+/Bi3+:ZnGa2O4 phosphors can be suitable for UC-based color tunable devices, green light emitting diodes and temperature sensing.

Influence of Bi2O3 co-doping on Cr-doped ZnGa2O4 red persistent phosphors synthesized by a liquid phase precursor process

The long persistence luminescent property of Cr-doped ZnG2O4 phosphor in the deep red/near-infrared region has been of great interest for the purpose of in vivo bioimaging application. Improving the optical property and afterglow lifetime of this material remain challenging. The microcrystalline cellulose assisted liquid phase precursor process was developed for the synthesis of high-quality ZnGa2O4 phosphors, which process enables uniform distribution of the dopant and co-dopant. In this paper, the co-doping of Bi enhanced the photoluminescence intensity by about 2.5 times, while significantly improving the long afterglow property. Investigation of the influence of the Bi addition indicated that the co-doping Bi not only serves to purify Cr ions in ZnGa2O4, but also brings about the growth of particles and changes in morphology through the role of flux.

Preparation and characterization of zinc gallate phosphor for electrochemical luminescence

Zinc gallate (ZnGa2O4) phosphor was fabricated by the direct precipitation method (DPM) and solid state reaction method (SSRM). The physicochemical and electrochemical properties of ZnGa2O4 phosphor were investigated using X-ray diffractometer (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and cyclic voltammetry (CV). Finally, the prepared ZnGa2O4 electrode was examined for electrochemical luminescence (ECL). The ZnGa2O4 phosphors showed nano-sized particles at about 10 nm for DPM and 75 nm for SSRM. This electrode showed good conductivity in the reducing hydrogen environment and enhanced luminescence efficiency. The ECL emission intensity of the ZnGa2O4 electrode of DPM was 30 times higher than that of SSRM. This electrode exhibited strong green emission peak intensity of ECL at a wavelength of 520 nm from the excitation of 254 nm wavelength. The nano-sized ZnGa2O4 electrode of DPM led to effective quenching in an ECL study. Therefore, it had a good luminescence stability.

Near-Infrared Light Excited Highly Pure Green Upconversion Photoluminescence and Intrinsic Optical Bistability Sensing in a Ho3+/Yb3+ Co-Doped ZnGa2O4 Phosphor through Li+ Doping

We report on highly pure green upconversion (UC) photoluminescence in a Ho3+/Yb3+/Li+ co-doped ZnGa2O4 phosphor prepared by the solid-state reaction method for the first time. The crystallite size,...

Afterglow, TL and OSL properties of Mn2+-doped ZnGa2O4 phosphor

Zinc gallate (ZnGa2O4) spinel ceramics doped with Mn2+ ions was prepared by a solid-state reaction at 1200 °C in air. Manganese concentration was equal to 0.05 mol.% of MnO with respect to ZnO. Ceramics produced in this way show an efficient green emission at about 505 nm under UV or X-ray excitations, which is caused by Mn2+ ions. This green emission is observed also as a relatively long afterglow (visible to the naked eye in the dark for about one hour) after switching-off the X-ray excitation. Time profiles of the beginning of glow and afterglow have been studied together with thermally stimulated (TSL) and optically stimulated (OSL) luminescence. Experimental results demonstrate a presence of few types of shallow and deep traps responsible for the observed afterglow and TSL/OSL emission of the material. The possibility of pulsed optical stimulation and time-resolved OSL characteristics of ZnGa2O4: Mn2+ has been reported for the first time. The presented results suggest the ZnGa2O4: Mn2+ spinel as a promising material for further fundamental research and possibility of application as a green long-lasting phosphor or storage phosphor for TSL/OSL radiation dosimetry.

A new recipe for the rapid microwave synthesis of high quantum yield Mn2+-doped ZnGa2O4 phosphors for potential forensic applications

A microwave recipe for the synthesis of phase pure and crystalline Mn2+-doped ZnGa2O4 phosphors in 5 minutes.

Concentration and pump power-mediated color tunability, optical heating and temperature sensing via TCLs of red emission in an Er3+/Yb3+/Li+ co-doped ZnGa2O4 phosphor

Intense red upconversion luminescence was observed in the Er3+/Yb3+/Li+ co-doped ZnGa2O4 phosphor synthesized through the solid state reaction method for the first time. The structural characterization showed a large crystalline nature and an increase in the particle size via Li+ doping. The absorption spectra showed a large number of peaks in the UV-vis-NIR regions due to the Er3+ and Yb3+ ions. The Er3+/Yb3+ co-doped ZnGa2O4 phosphor exhibited green, red and NIR upconversion emissions on excitation with 980 nm radiation. The intensity of the red emission was relatively larger than that of the other emissions. The luminescence intensity versus pump power measurements revealed the number of required photons for these emissions. The phosphor showed very interesting color tunability as a function of Er3+ ion concentration and incident pump power. The luminescence intensity of the Er3+/Yb3+ co-doped phosphor was enhanced more than two times via Li+ doping. The enhancement in the luminescence intensity was proposed to be due to the increase in the crystallinity and particle size of the phosphor. The lifetimes of the 4S3/2 and 4F9/2 levels also increased in the presence of Li+ ions. The variation in the fluorescence intensity ratio (FIR) of the thermally coupled levels (TCLs) of the red emission with incident pump power offered effective optical heating in the phosphor. The temperature-induced FIR using TCLs of red emission exhibited a larger value of temperature sensing sensitivity in the presence of Li+ ions, which was up to 14 × 10−4 K−1. Thus, the Er3+/Yb3+/Li+ co-doped ZnGa2O4 phosphor may be used in photonic, optical heating, and temperature sensing devices.

Controlling the white phosphorescence ZnGa2O4 phosphors by surface defects

White phosphorescence that lasted ≈ 212 s, being the longest phosphorescence time reported so far for any Ga based material, has been observed in undoped ZnGa2O4 (ZGO) phosphors. The samples were synthesized by a simple combustion method by using two different Gallium precursors (Gallium nitrate and Gallium Acetylacetonate). According to the X-ray diffraction analysis, the samples prepared with the two different precursors presented the same single cubic phase. TEM images demonstrated that the ZGO phosphors made with both precursors are formed by nanoparticles with quasi-spherical shape, and they have nanoparticle sizes in the range of 17–43 nm. When excited with UV light (400 nm), these phosphors produced a broad blue-green-yellow luminescence. The blue band was associated to transitions from the Ga-O levels, while that of green-yellow band was attributed to radiative transitions from oxygen vacancies. Particularly, the sample synthesized with Gallium acetylacetone precursor presented the highest phosphorescent emission intensity and had a CIE coordinates of (x = 0.27, y = 0.33), which is close to that for pure white light (x = 0.33, y = 0.33). Since the ZGO presented a white phosphorescent emission without doping with rare earths, they could be good candidates for lighting or signaling applications.