Tailoring Trap Depth and Emission Wavelength in Y3Al5âxGaxO12

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Functional Inorganic Materials and Devices

Tailoring Trap Depth and Emission Wavelength in Y3Al5xGaxO12:Ce3+,V3+ Phosphor-in-Glass Films for Optical Information Storage Wuhui Li, Yixi Zhuang, Peng Zheng, Tian-Liang Zhou, Jian Xu, Jumpei Ueda, Setsuhisa Tanabe, Le Wang, and Rong-Jun Xie ACS Appl. Mater. Interfaces, Just Accepted Manuscript • DOI: 10.1021/acsami.8b10713 • Publication Date (Web): 25 Jul 2018 Downloaded from http://pubs.acs.org on July 25, 2018

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ACS Applied Materials & Interfaces

Tailoring Trap Depth and Emission Wavelength in Y3Al5-xGaxO12:Ce3+,V3+ Phosphor-in-Glass Films for Optical Information Storage Wuhui Li,1 Yixi Zhuang,*,1 Peng Zheng,1 Tian-Liang Zhou,1 Jian Xu,2 Jumpei Ueda,2 Setsuhisa Tanabe,2 Le Wang,*,3 and Rong-Jun Xie*,1 1

College of Materials, Xiamen University, Simingnan-Road 422, Xiamen, 361005, P.R. China

2

Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-

nihonmatsu-cho, Sakyo-ku, Kyoto, 606-8501, Japan 3

College of Optical and Electronic Technology, China Jiliang University, Xueyuan-Street 258,

Hangzhou, 310018, P.R. China

KEYWORDS: persistent luminescence, trap depth engineering, Phosphor-in-Glass, garnet, Ce3+, optical information storage

ACS Paragon Plus Environment

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ABSTRACT: Deep-trap persistent luminescence materials, due to their exceptional ability of energy storage and controllable photon release under external stimulation, have attracted considerable attention in the field of optical information storage. Currently, the lack of suitable materials is still the bottleneck that restrains their practical applications. Herein, we successfully synthesized a series of deep-trap persistent luminescence materials Y3Al5-xGaxO12:Ce3+,V3+ (x = 0 - 3) with garnet structure and developed novel Phosphor-in-Glass (PiG) films containing these phosphors. The synthesized PiG films exhibited sufficiently deep traps, narrow trap depth distributions, high trap density, high quantum efficiency, and excellent chemical stability, which solved the problem of chemical stability at high temperatures in reported Phosphor-in-Silicone (PiS) films. Moreover, the trap depth in the phosphors and PiG films could be tailored from 1.2 to 1.6 eV thanks to the band-gap engineering effect, and the emission color was simultaneously changed from green to yellow due to the variation of crystal field strength. Image information was recorded on the PiG films by using a 450 nm blue-light laser in a laser direct writing (LDW) mode and the recorded information was retrieved under high-temperature thermal stimulation or photo-stimulation. The Y3Al5-xGaxO12:Ce3+,V3+ PiG films as presented in this work are very promising in the applications of multi-dimensional and rewritable optical information storage.


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■ INTRODUCTION Optical storage is a hopeful green storage technology that possesses many advantages, such as high capacity, low power-consumption, excellent rewritability, and environmental friendliness.1-3 With the fast development of the Information Age, great progress has been made on the optical storage technology in the past decays.4-7 However, the future development of the conventional optical information storage media has encountered a bottleneck due to the resolution limit in the two-dimensional (2D) space.8-10 Alternatively, multi-dimensional optical information storage, which presents great potentials to increase the capacity by orders of magnitude, is considered as the next-generation optical storage technology. Although several innovative strategies based on information multiplexing technology such as wavelength-, intensity-, polarization-, and lifetimemultiplexing have been proposed,9-12 there is still an urgent requirement to develop appropriate storage materials to realize their practical applications in the multi-dimensional optical information storage. Persistent luminescence materials are a group of luminescent materials possessing the extraordinary storage ability for incident photons and long-lasting emissions under thermal or other stimulations,13-17 thus have received extensive concerns in the fields of emergency lighting signs,18-22 in vivo bio-imaging,23-33 alternating current-light emitting diodes (AC-LEDs),34-38 and optical information storage.39-45 For example, SrAl2O4:Eu2+,Dy3+ phosphors, that give bright emissions for more than 10 h at room temperature (RT) after removal of excitation source, have been commercially used as emergency lighting signs in case of electronic power supply cut-off.22 Near-infrared (NIR) persistent luminescent nano-particles have found potential applications in the in vivo bio-imaging technology due to the merits of autofluorescence-free detection and high sign-to-noise ratio.46 Persistent luminescence phosphors were also used in AC-LEDs to reduce


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the serious flicker effect, which avoid additional electric power consumption during the AC to DC conversion.47 For the applications in optical information storage, the incident photons are captured by charge carrier traps during irradiation by input light beam, which is corresponded to an information recording process. The trapped charge carriers can be released under external stimulations. This process delivers output signals containing specific spectral characteristics, which are promising for multi-dimensional optical information storage systems by using intensity-multiplexing or wavelength-multiplexing technologies.24, 48 It should be noted that the trap depths in persistent luminescence materials for the former three applications are typically in the range of 0.5 - 0.8 eV.49 For the information storage application, the trap depth should be much deeper (> 1.2 eV) to restrain the spontaneous release by thermal stimulation at RT. Although the deep-trap persistent luminescence materials attracts much attention in recent years, only a few compounds containing deep traps have been reported till now.39-44,

48, 50-51

The

research on tailoring the emission wavelength and trap depth in persistent luminescence materials for optical information storage is still on its infancy. We

reported

3+ 3+ xGaxO12:Ce ,Cr

a

series

of

garnet-type

persistent

luminescence

phosphors

Y3Al5-

(x = 0 - 5) with tunable trap depths and emission colors in 2014.18 In these

materials, Ce3+ ions worked as luminescence centers (electron donors) and Cr3+ ions served as trap centers (electron acceptors) accounting for the Ce3+-Cr3+/Ce4+-Cr2+ redox couple during the trapping-detrapping process.52-53 Remarkably, the trap depth could be controlled from 0.41 to 1.08 eV by varying the Ga contents, while it was still too shallow for the applications in optical information storage. Recently, after screening several 3d transition metal ions, we found that V3+ ions might create deeper traps than Cr3+ ions in Y3Al5-xGaxO12:Ce3+.54 Considering the high luminous efficiency, excellent chemical stability, tunable band-structures of garnet


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compounds,55-60 it is of great necessity to perform a systematical investigation on the trap depth distribution in the Y3Al5-xGaxO12:Ce3+,V3+ garnet phosphors and discuss their potential applications in optical information storage. In another previous work,39-40 we reported deep-trap persistent luminescence phosphors (Sr,Ba)Si2O2N2:Ln2+,Dy3+ (Ln2+ = Eu2+ or Yb2+) in silicone resins. Obvious deterioration was not observed in those Phosphor-in-Silicone (PiS) films after heating to 150 ºC. Nevertheless, the chemical stability of the PiS films could be a severe problem for high-temperature applications (> 300 ºC) due to the possible decomposition of silicone resin. Contrarily, Phosphor-in-Glass (PiG) with the merits of outstanding chemical stability, mechanical strength, and thermal conductivity have found extensive applications in high-power white-LEDs or laser-driven white lighting.61-65 By using PiG composites instead of PiS to prepare phosphor films, we expect that the chemical stability of films can be greatly enhanced, which are vital for the rewritability and reliability of information storage media. In this study, we developed novel PiG films containing Y3Al5-xGaxO12:Ce3+,V3+ deep-trap persistent luminescence phosphors, which solved the problem of chemical stability in PiS films at high temperatures. The focus of this study was also put on tailoring the trap depth distribution and emission wavelength in the synthesized phosphors and PiG films. We used a 450 nm bluelight laser beam to record image information on these PiG films and retrieved the recorded information in different emission colors under high-temperature thermal stimulation or 808 nm NIR photo-stimulation. This work indicated that the Y3Al5-xGaxO12:Ce3+,V3+ PiG films showed great promise in the applications of optical information storage.


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■ EXPERIMENTAL SECTION Chemicals and Materials. Chemical reagents Ga2O3 (4N), V2O5 (3N), Y2O3 (5N), and CeO2 (5N) were received from Zhong-Nuo-Xin-Cai (Beijing) Corporation. Al2O3 (4N) were purchased from Aladdin Corporation. Terpineol (95%), 2-(2-butoxyethoxy) ethyl acetate (98%), and ethyl cellulose (18-22 mPa·s) used as organic vehicles were received from Aladdin Corporation. Silicone resins (6037-30 A/B) were obtained from Jieguo New Material Corporation. Sapphire substrates with a size of Φ40 mm × 1.3 mm or 10 mm × 10 mm × 0.3 mm were purchased from Crystal-Optech. Corundum ceramic balls (Al2O3 > 99%, Φ5 mm) were used in ball-milling processes. Corundum crucibles (Al2O3 > 99%, Φ30 mm × 28 mm) were used as sample holders in phosphor sintering. Synthesis of Persistent Luminescence Phosphors. Persistent luminescence phosphors with compositions of Y2.985Al4.998-xGaxO12:Ce0.015,V0.002 (x = 0, 1, 2, and 3) were synthesized by a high-temperature solid-state reaction. Stoichiometric starting materials of Al2O3, Ga2O3, Y2O3, CeO2, and V2O5 were milled with Al2O3 ceramic balls and anhydrous alcohol in a planet-type ball mill at 300 rpm for 16 h. The ball-milled mixtures were sieved, rinsed with anhydrous alcohol, and dried in an oven at 80 °C for 6 h. A part of the as-obtained powders was compressed into pellets of Φ10 mm × 2 mm. The as-obtained powders and pellets were transferred to Al2O3 crucibles and sintered at 1650 °C for 12 h under air atmosphere. For simplicity, the persistent luminescence phosphors or pellets with the compositions of Y2.985Al4.998-xGaxO12:Ce0.015,V0.002 (x = 0, 1, 2, and 3) are denoted as YAGG-0, YAGG-1, YAGG-2, and YAGG-3, respectively.


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Preparation of PiG and PiS Films. PiG films were fabricated by using a blade-coating method as reported in literature with a minor modification.64 Briefly, the synthesized phosphors were crushed into fine powers. The phosphors were blent with glass powders and organic vehicles in a weight ratio of 4:1:2 to form viscous phosphor slurries. The phosphor slurries were carefully flowed on a thin layer of single-crystal sapphire substrate. The upper surfaces of the phosphor slurries were slicked smooth using a sheet of glass. The size of the slurries was controlled to be 28 mm * 28 mm * 1 mm by using baffle plates. We heated the phosphor slurries first on a hot stage at 120 °C for 10 min for air-bubble-removing and preliminary shaping. The films were sintered in a muffle furnace at 850 °C for 30 min to eliminate the organics. After cooling to RT naturally, PiG films were finally obtained. Hereinafter, the PiG films containing the phosphors YAGG-0, YAGG-1, YAGG-2, and YAGG-3 are referred to PiG-0, PiG-1, PiG-2, and PiG-3, respectively. In order to compare the chemical stability of the host materials for persistent luminescence phosphors, PiS films were also prepared. The phosphor slurries were composed of the assynthesized phosphors YAGG-0 and silicone resins in a weight ratio of 1:1. After degassed for 10 min in a vacuum oven, the phosphor slurries were moulded on a thin layer of sapphire substrate. The PiS films were obtained after heating at 80 °C for 1 h and 200 °C for 3 h in an oven. Structural and Optical Characterizations. X-ray diffraction (XRD) patterns of the as-prepared phosphors and PiGs were measured by using an X-ray diffractometer (Bruker, D8 Advance) with Cu Kα radiation. The scanning interval and speed were set at 0.02 ° and 10 °/min, respectively. The microstructure was observed in a field-emission scanning electronic microscope (SEM, Hitachi, SU70). The photoluminescence excitation (PLE) and Photoluminescence (PL) spectra of


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the samples were recorded in a fluorescence spectrophotometer (Edinburgh Instrument, FLS980). A charge-coupled device (CCD) spectrometer (Ocean Optics, USB2000+) coupled with a cooling/heating stage (Linkam, THMS600E) was used to monitor the temperaturedependent PL spectra. The excitation source was a 420 nm LED lamp. Fluorescence quantum yield (QY) at room temperature (RT) was measured by using an absolute QY spectrometer (Hamamatsu, C11347). We set up a measurement system to record the persistent luminescence decay curves. The schematic diagram for the measurement system is given in Figure S1, Supporting Information (SI). A 460 nm blue-light LED was selected as excitation source of the persistent luminescence spectra and decay curve measurements. The persistent luminescence intensity was synchronically recorded by a filter-attached photomultiplier tube (PMT, Hamamatsu, R928P) and a luminance meter (Evenfine, LM-5). In order to record the thermoluminescence (TL) glow curves of the samples, an automatic measurement system driven by LabVIEW-based operation programs was constructed (see schematic diagram in Figure S2, SI). Firstly, the sample was cooled to a low temperature and exposed by a xenon lamp for 20 s. After ceasing the excitation, the TL signals were monitored by a PMT detector from 85 to 675 K. Considering the thermal quenching effect, all of the acquired TL glow curves were calibrated by using the temperature dependence of PL intensity. Persistent luminescence spectra at RT or elevated temperatures were obtained by using a CCD spectrometer (Ocean Optics, QE Pro). Photographs of the samples were taken with a digital camera (Canon, EOS 5D Mark II) in allmanual modes. Optical Information Recording and Readout. We adopted a laser direct writing (LDW) technology to record image information on PiG films by utilizing a commercialized micro-laser engraving machine (K-Bot, K-Bot V3). The laser engraving machine operated in a 2D


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progressive scan (bit-by-bit) mode. The scanning interval and the engraving time for 1 pixel were 0.075 mm and 10 ms, respectively. A 450 nm laser beam (beam diameter, 0.2 mm; maximum output, 1000 mW) was loaded in the laser engraving machine. For information readout, the PiG films were heated to 250 ºC or photo-stimulated by a NIR laser peaked at 808 nm (~2 W). The light spot was modulated to a rectangle in 5 mm × 1 mm. Photographs of the luminescent patterns under photo-stimulation were taken by a digital camera in the dark (schematic diagram given in Figure S3, SI).

■ RESULTS AND DISCUSSION Structural and Optical Characterizations of Deep-Trap Persistent Luminescence Phosphors YAGG:Ce,V. According to the XRD measurements, pure phases of garnet-type poly-crystals were obtained in the as-prepared YAGG phosphors (see Figure S4, SI). With increasing the Ga content from 0 to 3, the XRD peaks gradually shifted to lower angles due to the lattice expansion by the substitution of larger Ga3+ ions for Al3+ ions at tetrahedral sites. The PLE spectra of the YAGG phosphors with different Ga contents are showed in Figure 1a. Two broad PLE bands at around 450 and 350 nm were assigned to Ce3+: 4f→5d1 and 4f→5d2 electronic transitions, respectively.66 The 4f→5d1 PLE band showed a blue-shift; while the 4f→ 5d2 band exhibited a red-shift with the increase of Ga content. Correspondingly, the PL emission band due to Ce3+: 5d1→4f transitions shifted to shorter wavelength from 555, 545, 535, to 525 nm under 450 nm excitation (Figure 1b).52 Note that no emission from V3+ or V5+ ions was detected in all the samples, indicating that the codoped V ions did not act as luminescent centers


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or energy acceptors from Ce3+ through energy transfer processes. We also measured the PL intensity as a function of temperature from 260 to 675 K in the four YAGG phosphors (Figures S5-S8, SI). The thermal quenching temperature T50%, which was defined as the temperature when the luminescence intensity became half of the intensity at 260 K, decreased from 595 to 335 K with the increase of Ga content. The QY of the YAGG phosphors at RT are compiled in Table S1, SI. The QY values of YAGG-0, YAGG-1, YAGG-2, and YAGG-3 were 65.2 %, 68.5 %, 65.7 %, and 26.9 %, respectively. As shown in Figure 3c, the TL glow curves in the four YAGG:Ce,V samples exhibited main peaks higher than RT. It is noteworthy that the main peak of the TL glow curves slightly increased from 540 to 545 K and decreased to 480 and 410 K when the Ga content x increased from 0 to 3. The TL results are in good agreement with our previous work.54


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Figure 1. Spectral characterization of Y3Al5-xGaxO12:Ce3+,V3+ (x = 0, 1, 2, and 3). (a) PLE, (b) PL spectra, and (c) TL glow curves of the as-prepared YAGG phosphors with different Ga contents. The monitoring wavelength for the PLE spectra was 555, 545, 535, and 525 nm for YAGG-0, YAGG-1, YAGG-2, and YAGG-3, respectively. The excitation wavelength for the PL spectra was 450 nm. The heating rate was fixed as10 K/min for the TL glow curves. (d) Stacked VRBE diagrams of Y3Al5-xGaxO12:Ce3+,V3+ (x = 0, 1, 2, and 3). The bottom of conduction band (EC) rose up from 0 to 1, and dropped down from 1 to 3. The top of valence band (EV) monotonously moved upward when x increased. Furthermore, we systematically investigated the trap depth distributions in the YAGG:Ce,V persistent luminescence phosphors according to a test procedure proposed by Van den Eeckhout et al.49 First, a series of TL glow curves pre-excited at various temperatures were measured (Figure 2a, and Figures S9, S10, S11, SI). Each TL glow curve was calibrated with the thermal quenching curves as given in Figures S5-8, SI. The calibrated TL glow curves were analyzed by using the initial rise method as given below: ‫ܫ‬ሺܶሻ = C ∙ exp ቀ−

ா

୩ా ∙்

ቁ

(1)

where E (eV) is the trap depth; kB (J/K) is the Boltzmann constant; T (K) is the temperature; C is a constant including the frequency factor s (s-1). By plotting ln(I) against 1/T, the lowtemperature regions of the curves resembled straight lines (Figure 2b, and Figures S12, S13, S14, SI). The depth of the shallowest occupied trap for each TL glow curve could be readily obtained according to the slope of a straight fitting line. In addition, the trap density was estimated from the difference of the integrated intensity between two neighboring TL glow curves. Figures 2c-f summarize the trap depth distribution of the YAGG:Ce,V phosphors with various Ga contents. All the four compounds contain deep traps (> 0.8 eV) in a narrow distribution (~ 0.2 eV). The


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maximum of trap density were located at 1.60, 1.62, 1.42, and 1.13 eV for YAGG-0, YAGG-1, YAGG-2, and YAGG-3, respectively. The trap depth distributions indicate that the deep-trap persistent luminescence phosphors YAGG:Ce,V are candidate materials for the application of optical information storage. We also measured the TL glow curve in a Y3Al5O12:Ce3+ phosphor for comparison, which gave rather weak TL signals in the temperature range from 85 to 650 K (see Figure S15, SI) due to intrinsic/lattice defects. Therefore, the deep traps in the YAGG:Ce,V system are probably originated from the doped V ions at Al/Ga sites. During the UV or blue light irradiation, excited electrons could be trapped by the trivalent V3+ ions, in a process as the following defect ୶ ᇱ chemistry reaction (in Kröger-Vink notation): V୅୪/ୋୟ + eᇱ = V୅୪/ୋୟ .54 Here, the superscripts x

and ' are referred to neutral charge and one negative charge, respectively.


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Figure 2. Trap depth distribution in the Y3Al5-xGaxO12:Ce3+,V3+ phosphors. (a) TL glow curves of YAGG-0. For each TL glow curve, the sample was pre-excited at a different temperature. The heating rate was set as 20 K/min. (b) Initial-rise-plotting of the TL glow curves in the YAGG-0 phosphor. The depth of the shallowest occupied trap for each curve was estimated according to the slope of a straight fitting line. (c-f) Trap depth distribution of the YAGG-0 (c), YAGG-1 (d), YAGG-2 (e), and YAGG-3 (f).The original TL glow curves and the initial rise analysis for YAGG-1, YAGG-2, and YAGG-3 are given in Figures S9-14, SI.


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We reconstructed the vacuum-referred binding energy (VRBE) diagrams of the Y3Al5xGaxO12:Ln

2+/3+

system (x = 0, 1, 2, and 3, Ln = rare-earth elements).67-68 The band gap energy

(Eg), the charge transfer energy for Eu3+ (ECT), and the Coulomb repulsive force [U(6, A)] were cited from Refs. 69, 70, and 71, respectively. The transition energy of Ce3+: 4f→5d1, 4f→5d2, as well as the trap depth from V2+ to the bottom of conduction band (EC) were adopted from the PLE spectra in Figure 1a and trap depth distribution in Figures 2c-f. The stacked VRBE diagrams for Y3Al5-xGaxO12:Ce3+,V3+ (x = 0, 1, 2, and 3) are given in Figure 1d. The 4f ground state of Ce3+ were all fixed at approximately -5.48 eV in the VRBE scheme. The Ce3+: 4f→5d1 transition energy increased from 2.64 to 2.82 eV and the 4f→5d2 energy decreased from 3.62 to 3.54 eV, which were attributed to a weaker crystal field strength for Ce3+ in a host with higher Ga content.69 The bottom of CB moved upward from YAGG-0 to YAGG-1, and declined with ᇱ higher Ga content. We also noticed that the energy of the V୅୪/ୋୟ trap level slightly shifted

upward with the increase of Ga content due to the sensitivity of outmost d electrons with the arrangement of surrounding ligands. Therefore, the variation of trap depth in the Y3Al53+ 3+ xGaxO12:Ce ,V

persistent luminescence phosphors should be majorly attributed to the band-

gap engineering effect of the Y3Al5-xGaxO12 host, and partially due to the energy shift of the V2+ trap center. Preparation and Optical Properties of PiG Films. Figure 3a shows the typical preparation procedures of PiG films by using the Y3Al5-xGaxO12:Ce3+,V3+ persistent luminescence phosphors. The detailed description of the preparation procedures is given in the experimental section. The SEM images indicated the particle size of the as-synthesized phosphors was 5 - 10 µm (Figure S16, SI); while the particles were crushed to 1 ~ 2 µm for the PiG preparation (Figure S17, SI).


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We compared the XRD patterns of the YAGG-0 phosphors and PiG-0 film in Figure 3b. The result showed that the Y3Al5O12 crystalline phase was well preserved in the PiG-0 film. Furthermore, the TL glow curves, PL spectra and persistent luminescence spectra of the YAGG0 phosphors and PiG-0 film were almost identical (Figures 3c-e), which indicated that the optical properties nearly kept constant after the PiG preparation. Therefore, the PiG preparation procedures offer a route to obtain phosphor films with the similar optical properties as the original persistent luminescence phosphors.


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Figure 3. Preparation procedures and optical properties of PiG films. (a) Schematic diagram for the preparation procedure of PiG films. (b) XRD patterns of the YAGG-0 phosphors and PiG-0 film. (c-e) TL glow curves (c), PL spectra (d), and persistent luminescence spectra (e) of the YAGG-0 phosphors and PiG-0 film. For the TL measurements, the samples were excited at 85 K by using a xenon lamp. The heating rate was fixed as 10 K/min. Note that the difference of spectral shapes in the PL spectra (Edinburgh Instrument, FLS 980) and the persistent luminescence spectra (Ocean Optics, QE Pro) was due to the different detectors in the measurements.

Chemical Stability of the PiG Films. In order to evaluate the chemical stability of the PiG films, we performed thermal aging tests between the PiG-0 and PiS-0 films. Figure 4a shows photographs of the two phosphor films before and after aging at 400 °C for 1 h. Obviously, the PiS-0 film shrank and cracked after aging for 1 h (from i to ii). On the contrary, the PiG-0 film did not show any change in appearance (from iii to iv). We also measured the PL spectra of the PiS-0 film before and after thermal aging (Figure 4b). Under 460 nm excitation, the PL intensity seriously declined after aging at 400 °C for 1 h. The deterioration of PL performance may be due to the decomposition of silicon resins above 300 °C. Contrarily, the PL spectra of the PiG-0 film were almost invariable after aged at 400 °C for 5 h (Figure 4c). The integrated PL intensity of the PiG-0 film and PiS-0 film as a function of aging time (Figure 4d) indicated that the PiG-0 film possessed much better chemical stability against thermal attack than the PiS-0 film. Thus, PiG films with superior thermal stability are particularly useful for high-temperature working conditions, e.g. 400 °C.


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Figure 4. Chemical stability of PiG films. (a) Photographic images of the PiS-0 and PiG-0 films before and after aging at 400 °C for 1h. (b-c) PL spectra of the PiS-0 (b) and PiG-0 (c) films under 460 nm excitation. The PiS-0 film was aged at 400 °C for 1h. The PiG-0 film was aged at 400 °C for 1 - 5 h. The ratio of peak intensity between 550 and 460 nm in the PiG-0 (0 h) was lower than that in the PiS-0 (0 h), which could be attributed to a pore structure in the PiG-0 sample after the sinter process at 850 ºC. (d) Integrated PL intensity as a function of aging time for PiS-0 and PiG-0 films. The integrated PL intensity without aging was normalized to 1.

Tailoring Trap Depth and Emission Wavelength in the PiG Films. Based on the preparation procedures shown in Figure 3a, we fabricated a series of PiG films containing different YAGG phosphors. The PiG films with a size of 28 mm * 28 mm were deposited on transparent sapphire


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substrates (see photographic images in Figure 5a, i). Under UV light, the PiG films showed various emission colors from yellow, yellowish-green, to green with the increase of Ga content (Figure 5a, ii). After ceasing the UV irradiation, almost no emission was observed at RT (Figure S18, SI), except for weak persistent luminescence in PiG-3. However, after placed on a hot plate at 250 ºC, the PiG films gave bright thermally stimulated luminescence (TSL). The TSL exhibited the similar emission color (Figure 5a, iii-viii) and emission spectra (Figure 5b) as those of PL. The TSL intensity in the PiG-0 film lasted for more than 20 min before it decayed to 0.32 mcd·m-2 (Figure S18, SI), indicating that a large number of electrons were trapped during the blue light excitation. Interestingly, green TSL came out of the PiG-3 film from the moment when loaded on the hot plate. For PiG-2, PiG-1, and PiG-0, there was an obvious rise-and-drop process for the TSL intensity (Figure 5c). The different time-response of the TSL should be attributed to the different trap distributions in these PiG films (Figure 5d and Figure 2). According to the above results, we successfully tailored the trap depth (majorly by a band-gap engineering effect) and the emission wavelength (by the variation of crystal field strength) in the PiG films containing Y3Al5-xGaxO12:Ce3+,V3+ persistent luminescence phosphors. As discussed in the introduction part, tailoring the trap depth and emission wavelength is of great importance in the application of multi-dimensional optical information storage.


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Figure 5. Tailoring trap depth and emission wavelength in the PiG films. (a) Photographic images of the PiG films with different Ga contents under natural light (i: NL), under 365nm UV excitation (ii: UV), and 1 s (iii), 5 s (iv), 10 s (v) , 20 s (vi), 30 s (vii), and 60 s (viii) after placed on a hot plate (250 °C) in the dark. The samples notated as 0, 1, 2, and 3 are PiG-0, PiG-1, PiG2, and PiG-3, respectively. The following parameters were kept constant: ISO value, 3200; aperture value, 2.8; exposure time, 1/4 s; and white balance, cloudy. (b) Normalized persistent luminescence spectra of the PiG films at 250 °C. (c) Persistent luminescence decay curves of the PiG films. The films were pre-excited by 365 nm UV light at RT and transferred to a hot plate at 250 °C. The persistent luminescence intensity was monitored from the moment when the films were deposited on the hot plate. (d) Normalized TL glow curves of the PiG films. The excitation source was a xenon lamp. The heating rate was set as 10 K/min for all the measurements.


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Applications to Optical Information Storage. The fabricated PiG films exhibit sufficiently deep traps (Figures 2 and 5d), a narrow trap depth distribution (Figure 2), high trap density (Figure S18, SI), high quantum efficiency (Table S1, SI), as well as excellent chemical stability (Figure 4), which are promising for the applications in optical information storage. By using these PiG films (Figure 6b), we set up a simple procedure of optical information recording and readout as schematically depicted in Figure 6a. Before recording, the films should be heated up to 400 ºC and quickly moved to a dark environment in order to clean up remaining trapped charge carriers. Optical information was recorded on the surface of PiG films by a commercial micro-laser (450 nm) engraving machine in the LDW mode (Figure 6a, ii). The recorded optical information was a black-white pattern, where the laser outputted in the black points and skipped in the white areas. Examples of two original patterns are given in Figure S19 and S20, SI. The recorded optical information should be stably stored at RT if the trap depths in these PiG films are sufficiently deep. The trapped charge carriers escape from deep traps only when large thermal energy (high-temperature thermal stimulation) or photon energy (photo-stimulation) are offered. Figures 6c and 6d show two examples of luminescent patterns read by a digital camera when the PiG-0 film was heated to 250 °C. The pre-recorded high-temperature alarm symbol on the PiG-0 film, which was “invisible” at RT and became visible at 250 °C (Figure 6c), clearly demonstrate its application as an optical warning signal for high-temperature environments in the dark. Addition to the high-temperature thermal stimulation, we also exploited the feasibility of information readout by photo-stimulation (schematic diagram given in Figure S3, SI). Figures 6e-h show the luminescent patterns on the four PiG films under 808 nm photo-stimulation. Interestingly, the PiG-2 and PiG-3 films gave intense emission when the 808 nm laser was


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projected on the surface. However, the photo-stimulated luminescence from the PiG-0 and PiG-1 films was rather weak. This result was reasonable because the photon energy (~1.53 eV) of the 808 nm laser was smaller than the depths for most traps in PiG-0 (1.60 eV) and PiG-1 (1.62 eV), thus insufficiently to release trapped electrons directly by electron transitions. By using shorterwavelength light (e.g. 650 nm laser), enhancement in the photo-stimulated luminescence efficiency in these films is expectable. We also evaluated the retention rate for the recorded optical information. The retention rate was estimated according to the integrated intensity of a series of TL glow curves after holding at RT for different durations (Figure S21, SI). The retention rate curve as a function of holding time showed that the signals lost fast in the beginning and flatten out in longer time (Figure S22, SI). After holding at RT for 30 days, the retention rate kept approximately 47% relative to the original intensity. Considering the abundant trap density and high luminescence efficiency as discussed above, the fabricated PiG films could be applied in the long-term optical information storage.


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Figure 6. Applications to optical information storage. (a) Schematic diagram of optical information recording and readout on a PiG film containing deep-trap persistent luminescence phosphors. (b) The PiG-0 film under natural light. (c-d) Photographic images of luminescent patterns readout from the PiG-0 film after heating to 250 °C in the dark. The patterns were recorded onto the film by using a 450 nm laser in the LDW mode beforehand. (e-h) Photographic images of luminescent patterns readout from the PiG-0 (e), PiG-1 (f), PiG-2 (g), and PiG-3 (h) films under 808 nm laser photo-stimulation. The light spot of 808 nm laser was modulated to a rectangle in 5 mm × 1 mm. The exposure time was 5, 5, 0.1, and 0.05 s for (e), (f), (g), and (h), respectively.


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■ CONCLUSION In summary, for the first time, we fabricated a series of PiG films containing deep-trap persistent luminescence phosphors, Y3Al5-xGaxO12:Ce3+,V3+ (x = 0 - 3) with garnet structure. On the one hand, the trap depth in the PiG films was tuned in the range of 1.13 - 1.62 eV by utilizing the band-gap engineering effect. On the other hand, their emission color was tailored from yellow, yellowish-green to green due to the variation of crystal filed strength on the Ce3+ 5d1 excited state. These PiG films possessed the similar optical properties as their parent persistent luminescence phosphors. The chemical stability of the PiG films were superior to their PiS counterparts. Consequently, we used these PiG films as storage media to store planar image information from a micro-laser engraving machine in the LDW mode. The recorded image information was stored at RT and retrieved under high-temperature thermal stimulation or NIR photo-stimulation. The readout signals exhibited different intensity and emission color, which were originated from the tailorable trap depth and crystal filed strength. The developed PiG films, due to their sufficiently deep traps, narrow depth distributions, high trap density, high quantum efficiency, as well as excellent chemical stability, showed great potentials in the applications of optical information storage.

■ ASSOCIATED CONTENT Supporting Information. Schematic diagrams of measurement systems for persistent luminescence decay curves, TL glow curves and photo-stimulation experiments; XRD patterns of the YAGG phosphors; temperature


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dependence of PL spectra; TL glow curves of the YAGG phosphors pre-excited at various temperatures; TL glow curves analyzed by the initial rise method; SEM image of the YAGG-0 phosphor and PiG-0 film; persistent luminescence decay curves of the PiG-0 film measured at RT and 250 ºC; original patterns for optical information recording; TL glow curves of the PiG-0 film with different holding time at RT; optical signal retention as a function of holding time; quantum yields of the YAGG phosphors with different Ga contents.

■ AUTHOR INFORMATION Corresponding Author *E-mail: [email protected]. *E-mail: [email protected]. *E-mail: [email protected]. Author Contributions Y.Z., and W.L. conceived and designed the experiments. R.X. and S.T. supervised the research. W.L., Y.Z., and J.X. were primarily responsible for data collection and analysis. W.L. and Y.Z. prepared figures and wrote the main manuscript text. All authors contributed to data analysis, discussions and manuscript preparation. All authors have given approval to the final version of the manuscript. Notes The authors declare no competing financial interest.


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■ Acknowledgment This work was financially supported by the National Natural Science Foundation of China (Grant Nos. 51572232, 51561135015, 51502254), National Key Research and Development Program (2017YFB0404301), and the Natural Science Foundation of Fujian Province (No. 2018J01080).

■ REFERENCES (1) Gu, M.; Li, X.; Cao, Y. Optical Storage Arrays: a Perspective for Future Big Data Storage. Light: Sci. Appl. 2014, 3, e177. (2) Gu, M.; Zhang, Q.; Lamon, S. Nanomaterials for Optical Data Storage. Nat. Rev. Mater. 2016, 1, 16070. (3) Trelles, O.; Prins, P.; Snir, M.; Jansen, R. C. Big Data, but Are We Ready? Nat. Rev. Genet. 2011, 12, 224. (4) Pham, H. H.; Gourevich, I.; Oh, J. K.; Jonkman, J. E. N.; Kumacheva, E. A Multidye Nanostructured Material for Optical Data Storage and Security Data Encryption. Adv. Mater. 2004, 16, 516-520. (5) Royon, A.; Bourhis, K.; Bellec, M.; Papon, G.; Bousquet, B.; Deshayes, Y.; Cardinal, T.; Canioni, L. Silver Clusters Embedded in Glass as a Perennial High Capacity Optical Recording Medium. Adv. Mater. 2010, 22, 5282-5286. (6) Zhang, J.; Gecevicius, M.; Beresna, M.; Kazansky, P. G. Seemingly Unlimited Lifetime Data Storage in Nanostructured Glass. Phys. Rev. Lett. 2014, 112, 033901.


25


Page 26 of 35

(7) Sun, B.; Sun, Y.; Wang, C. Encoding Optoelectrical Sub-Components in an Al2O3 Nanowire for Rewritable High-Resolution Nanopatterning. Nano Lett. 2018, DOI: 10.1021/acs.nanolett.8b00985. (8) Liu, Y.; Lu, Y.; Yang, X.; Zheng, X.; Wen, S.; Wang, F.; Vidal, X.; Zhao, J.; Liu, D.; Zhou, Z.; Ma, C.; Zhou, J.; Piper, J. A.; Xi, P.; Jin, D. Amplified Stimulated Emission in up Conversion Nanoparticles for Super-Resolution Nanoscopy. Nature 2017, 543, 229-233. (9) Zijlstra, P.; Chon, J. W.; Gu, M. Five-Dimensional Optical Recording Mediated by Surface Plasmons in Gold Nanorods. Nature 2009, 459, 410-413. (10) Van der Heggen, D.; Joos, J. J.; Rodriguez Burbano, D. C.; Capobianco, J. A.; Smet, P. F. Counting the Photons: Determining the Absolute Storage Capacity of Persistent Phosphors. Materials 2017, 10, 867. (11) Li, X.; Chon, J. W. M.; Wu, S. Rewritable Polarization-Encoded Multilayer Data Storage in 2,5-Dimethyl-4-(p-nitrophenylazo) Anisole Doped Polymer. Opt. Lett. 2007, 32, 277-279. (12) Lu, Y.; Zhao, J.; Zhang, R.; Liu, Y.; Liu, D.; Goldys, E. M.; Yang, X.; Xi, P.; Sunna, A.; Lu, J.; Shi, Y.; Leif, R. C.; Huo, Y.; Shen, J.; Piper, J. A.; Robinson, J. P.; Jin, D. Tunable Lifetime Multiplexing Using Luminescent Nanocrystals. Nat. Photonics 2013, 8, 32-36. (13) Li, Y.; Gecevicius, M.; Qiu, J. Long Persistent Phosphors-from Fundamentals to Applications. Chem. Soc. Rev. 2016, 45, 2090-2136. (14) Smet, P. F.; Botterman, J.; Van den Eeckhout, K.; Korthout, K.; Poelman, D. Persistent Luminescence in Nitride and Oxynitride Phosphors: A Review. Opt. Mater. 2014, 36, 19131919.


26

Page 27 of 35 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(15) Zhuang, Y.; Katayama, Y.; Ueda, J.; Tanabe, S. A Brief Review on Red to Near-Infrared Persistent Luminescence in Transition-Metal-Activated Phosphors. Opt. Mater. 2014, 36, 19071912. (16) Brito, H. F.; Hölsä, J.; Laamanen, T.; Lastusaari, M.; Malkamäki, M.; Rodrigues, L. C. V. Persistent Luminescence Mechanisms: Human Imagination at Work. Opt. Mater. Express 2012, 2, 371-381. (17) Bos, A. J. J. Thermoluminescence as a Research Tool to Investigate Luminescence Mechanisms. Materials 2017, 10, 1357. (18) Ueda, J.; Kuroishi, K.; Tanabe, S. Bright Persistent Ceramic Phosphors of Ce3+-Cr3+Codoped Garnet Able to Store by Blue Light. Appl. Phys. Lett. 2014, 104, 3-7. (19) Kabe, R.; Adachi, C. Organic Long Persistent Luminescence. Nature 2017, 550, 384-387. (20) Trojan-Piegza, J.; Niittykoski, J.; Hölsä, J.; Zych, E. Thermoluminescence and Kinetics of Persistent Luminescence of Vacuum-Sintered Tb3+-Doped and Tb3+,Ca2+-Codoped Lu2O3 Materials. Chem. Mater. 2008, 20, 2252-2261. (21) Ueda, J.; Miyano, S.; Tanabe, S. Formation of Deep Electron Traps by Yb3+ Codoping Leads to Super-Long Persistent Luminescence in Ce3+-Doped Yttrium Aluminum Gallium Garnet Phosphors. ACS Appl. Mater. Interfaces 2018, DOI: 10.1021/acsami.8b02758. (22) Matsuzawa, T.; Aoki, Y.; Takeuchi, N.; Murayama, Y. New long phosphorescent phosphor with high brightness, SrAl2O4:Eu2+,Dy3+. J. Electrochem. Soc. 1996, 143, 2670-2673. (23) Pan, Z.; Lu, Y. Y.; Liu, F. Sunlight-Activated Long-Persistent Luminescence in the NearInfrared from Cr3+-doped Zinc Gallogermanates. Nat. Mater. 2011, 11, 58-63.


27


Page 28 of 35

(24) Gluchowski, P.; Strek, W.; Lastusaari, M.; Holsa, J. Optically Stimulated Persistent Luminescence of Europium-Doped LaAlO3 Nanocrystals. Phys. Chem. Chem. Phys. 2015, 17, 17246-17252. (25) Zhou, Z.; Zheng, W.; Kong, J.; Liu, Y.; Huang, P.; Zhou, S.; Chen, Z.; Shi, J.; Chen, X. Rechargeable and LED-Activated ZnGa2O4 : Cr3+ Near-Infrared Persistent Luminescence Nanoprobes for Background-Free Biodetection. Nanoscale 2017, 9, 6846-6853. (26) Allix, M.; Chenu, S.; Véron, E.; Poumeyrol, T.; Kouadri-Boudjelthia, E. A.; Alahraché, S.; Porcher, F.; Massiot, D.; Fayon, F. Considerable Improvement of Long-Persistent Luminescence in Germanium and Tin Substituted ZnGa2O4. Chem. Mater. 2013, 25, 1600-1606. (27) Li, Z.; Zhang, Y.; Wu, X.; Huang, L.; Li, D.; Fan, W.; Han, G. Direct Aqueous-Phase Synthesis of Sub-10 nm "Luminous Pearls" with Enhanced in Vivo Renewable Near-Infrared Persistent Luminescence. J. Am. Chem. Soc. 2015, 137, 5304-5307. (28) Shi, J.; Sun, X.; Li, J.; Man, H.; Shen, J.; Yu, Y.; Zhang, H. Multifunctional Near InfraredEmitting Long-Persistence Luminescent Nanoprobes for Drug Delivery and Targeted Tumor Imaging. Biomaterials 2015, 37, 260-270. (29) Bessière, A.; Sharma, S. K.; Basavaraju, N.; Priolkar, K. R.; Binet, L.; Viana, B.; Bos, A. J. J.; Maldiney, T.; Richard, C.; Scherman, D.; Gourier, D. Storage of Visible Light for LongLasting Phosphorescence in Chromium-Doped Zinc Gallate. Chem. Mater. 2014, 26, 1365-1373. (30) Zou, R.; Gong, S.; Shi, J.; Jiao, J.; Wong, K.-L.; Zhang, H.; Wang, J.; Su, Q. Magnetic-NIR Persistent Luminescent Dual-Modal ZGOCS@MSNs@Gd2O3 Core–Shell Nanoprobes for in Vivo Imaging. Chem. Mater. 2017, 29, 3938-3946.


28

Page 29 of 35 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(31) Zhuang, Y.; Ueda, J.; Tanabe, S. Tunable Trap Depth in Zn(Ga1−xAlx)2O4:Cr,Bi Red Persistent Phosphors: Considerations of High-Temperature Persistent Luminescence and Photostimulated Persistent Luminescence. J. Mater. Chem. C 2013, 1, 7849-7855. (32) Xu, J.; Murata, D.; Ueda, J.; Viana, B.; Tanabe, S. Toward Rechargeable Persistent Luminescence for the First and Third Biological Windows via Persistent Energy Transfer and Electron Trap Redistribution. Inorg. Chem. 2018, 57, 5194-5203. (33) Xu, J.; Murata, D.; Katayama, Y.; Ueda, J.; Tanabe, S. Cr3+/Er3+ Co-Doped LaAlO3 Perovskite Phosphor: a Near-Infrared Persistent Luminescence Probe Covering the First and Third Biological Windows. J. Mater. Chem. B 2017, 5, 6385-6393. (34) Lin, H.; Wang, B.; Xu, J.; Zhang, R.; Chen, H.; Yu, Y.; Wang, Y. Phosphor-in-Glass for High-Powered Remote-Type White AC-LED. ACS Appl. Mater. Interfaces 2014, 6, 2126421269. (35) Lin, H.; Xu, J.; Huang, Q.; Wang, B.; Chen, H.; Lin, Z.; Wang, Y. Bandgap Tailoring via Si Doping in Inverse-Garnet Mg3Y2Ge3O12:Ce3+ Persistent Phosphor Potentially Applicable in ACLED. ACS Appl. Mater. Interfaces 2015, 7, 21835-21843. (36) Liu, Y. F.; Liu, P.; Wang, L.; Cui, C. E.; Jiang, H. C.; Jiang, J. A Two-Step Solid-State Reaction to Synthesize the Yellow Persistent Gd3Al2Ga3O12:Ce3+ Phosphor with an Enhanced Optical Performance for AC-LEDs. Chem. Commun. 2017, 53, 10636-10639. (37) Yeh, C.-W.; Li, Y.; Wang, J.; Liu, R.-S. Appropriate Green Phosphor of SrSi2O2N2 Eu2+,Mn2+ for AC LEDs. Opt. Express 2012, 20, 18031-18043. (38) Lin, H.; Wang, B.; Huang, Q.; Huang, F.; Xu, J.; Chen, H.; Lin, Z.; Wang, J.; Hu, T.; Wang, Y. Lu2CaMg2(Si1−xGex)3O12:Ce3+ Solid-Solution Phosphors: Bandgap Engineering for BlueLight Activated Afterglow Applicable to AC-LED. J. Mater. Chem. C 2016, 4, 10329-10338.


29


Page 30 of 35

(39) Zhuang, Y.; Wang, L.; Lv, Y.; Zhou, T.-L.; Xie, R.-J. Optical Data Storage and Multicolor Emission Readout on Flexible Films Using Deep-Trap Persistent Luminescence Materials. Adv. Funct. Mater. 2018, 28, 1705769. (40) Zhuang, Y.; Lv, Y.; Wang, L.; Chen, W.; Zhou, T. L.; Takeda, T.; Hirosaki, N.; Xie, R. J. Trap Depth Engineering of SrSi2O2N2:Ln2+,Ln3+ (Ln2+ = Yb, Eu; Ln3+ = Dy, Ho, Er) Persistent Luminescence Materials for Information Storage Applications. ACS Appl. Mater. Interfaces 2018, 10, 1854-1864. (41) Xu, X.; Yan, L.; Yu, X.; Yu, H.; Jiang, T.; Jiao, Q.; Qiu, J. Concentration-Dependent Effects of Optical Storage Properties in CSSO:Dy. Mater. Lett. 2013, 99, 158-160. (42) Wang, B.; Li, X.; Chen, Y.; Chen, Y.; Zhou, J.; Zeng, Q. Long Persistent and PhotoStimulated Luminescence in Pr3+-Doped Layered Perovskite Phosphor for Optical Data Storage. J. Am. Ceram. Soc. 2018, DOI: 10.1111/jace.15703. (43) Wang, C.; Jin, Y.; Lv, Y.; Ju, G.; Liu, D.; Chen, L.; Li, Z.; Hu, Y. Trap Distribution Tailoring Guided Design of Super-Long-Persistent Phosphor Ba2SiO4:Eu2+,Ho3+ and Photostimulable Luminescence for Optical Information Storage. J. Mater. Chem. C 2018, 6, 6058-6067. (44) Wang, W.; Yang, J.; Zou, Z.; Zhang, J.; Li, H.; Wang, Y. An Isolated Deep-Trap Phosphor for Optical Data Storage. Ceram. Int. 2018, 44, 10010-10014. (45) Ruan, J.; Yang, Z.; Huang, A.; Zhang, H.; Qiu, J.; Song, Z. Thermomchromic ReactionInduced Reversible Upconversion Emission Modulation for Switching Devices and Tunable Upconversion Emission Based on Defect Engineering of WO3:Yb3+,Er3+ Phosphor. ACS Appl. Mater. Interfaces 2018, 10, 14941-14947.


30

Page 31 of 35 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(46) Wang, J.; Li, J.; Yu, J.; Zhang, H.; Zhang, B. Large Hollow Cavity Luminous Nanoparticles with Near-Infrared Persistent Luminescence and Tunable Sizes for Tumor Afterglow Imaging and Chemo-/Photodynamic Therapies. ACS Nano 2018, 12, 4246-4258. (47) Onushkin, G. A.; Young-Jin, L.; Jung-Ja, Y.; Hyung-Kun, K.; Joong-Kon, S.; Gil-Han, P.; YongJo, P. Efficient Alternating Current Operated White Light-Emitting Diode Chip. IEEE Photonics Technol. Lett. 2009, 21, 33-35. (48) Thoms, M.; von Seggern, H.; Winnacker, A. Spatial Correlation and Photostimulability of Defect Centers in the X-Ray-Storage Phosphor BaFBr:Eu2+. Phys. Rev. B 1991, 44, 9240-9247. (49) Van den Eeckhout, K.; Bos, A. J. J.; Poelman, D.; Smet, P. F. Revealing Trap Depth Distributions in Persistent Phosphors. Phys. Rev. B 2013, 87, 045126. (50) Liu, F.; Yan, W.; Chuang, Y. J.; Zhen, Z.; Xie, J.; Pan, Z. Photostimulated Near-Infrared Persistent Luminescence as a New Optical Read-out from Cr3+-doped LiGa5O8. Sci. Rep. 2013, 3, 1554-1562. (51) Wang, J.; Zhang, H.; Liu, Y.; Dong, H.; Lei, B.; Zheng, M.; Xiao, Y.; Peng, M.; Wang, J. Insights into Luminescence Quenching and Detecting Trap Distribution in Ba2Si5N8:Eu2+ Phosphor with Comprehensive Considerations of Temperature-Dependent Luminescence Behaviors. J. Mater. Chem. C 2015, 3, 9572-9579. (52) Ueda, J.; Dorenbos, P.; Bos, A. J. J.; Kuroishi, K.; Tanabe, S. Control of Electron Transfer between Ce3+ and Cr3+ in the Y3Al5−xGaxO12 Host via Conduction Band Engineering. J. Mater. Chem. C 2015, 3, 5642-5651. (53) Ueda, J.; Katayama, M.; Asami, K.; Xu, J.; Inada, Y.; Tanabe, S. Evidence of Valence State Change of Ce3+ and Cr3+ during UV Charging Process in Y3Al2Ga3O12 Persistent Phosphors. Opt. Mater. Express 2017, 7, 2471-2476.


31


Page 32 of 35

(54) Ueda, J.; Hashimoto, A.; Takemura, S.; Ogasawara, K.; Dorenbos, P.; Tanabe, S. Vacuum Referred Binding Energy of 3d Transition Metal Ions for Persistent and Photostimulated Luminescence Phosphors of Cerium-Doped Garnets. J. Lumin. 2017, 192, 371-375. (55) Chiang, C.-C.; Tsai, M.-S.; Hon, M.-H. Luminescent Properties of Cerium-Activated Garnet Series Phosphor: Structure and Temperature Effects. J. Electrochem. Soc. 2008, 155, B517. (56) Asami, K.; Ueda, J.; Kitaura, M.; Tanabe, S. Investigation of Luminescence Quenching and Persistent Luminescence in Ce3+ Doped (Gd,Y)3(Al,Ga)5O12 Garnet Using Vacuum Referred Binding Energy Diagram. J. Lumin. 2018, 198, 418-426. (57) Jr., W. W. H.; Kestigian, M. Optical Properties of Cerium-Activated Garnet Crystals. J. Opt. Soc. Am. 1969, 59, 60-63. (58) Fujita, S.; Sakamoto, A.; Tanabe, S. Luminescence Characteristics of YAG Glass-Ceramic Phosphor for White LED. IEEE J. Sel. Top. Quantum Electron. 2008, 14, 1387-1391. (59) Tanabe, S.; Fujita, S.; Sakamoto, A.; Yamamoto, S. Glass Ceramics for Solid-State Lighting. Ceram.Trans. 2006, 173, 19-25. (60) Blasse, G.; Bril, A. A New Phosphor for Flying-Spot Cathode-Ray Tures for Color Television: Yellow-Emission Y3Al5O12-Ce3+. Appl. Phys. Lett. 1967, 11, 53-55. (61) Zhang, X.; Yu, J.; Wang, J.; Lei, B.; Liu, Y.; Cho, Y.; Xie, R.-J.; Zhang, H.-W.; Li, Y.; Tian, Z.; Li, Y.; Su, Q. All-Inorganic Light Convertor Based on Phosphor-in-Glass Engineering for Next-Generation Modular High-Brightness White LEDs/LDs. ACS Photonics 2017, 4, 986995. (62) Chen, D.; Zhou, Y.; Xu, W.; Zhong, J.; Huang, P. Persistent and Photo-stimulated Luminescence in Ce3+/Cr3+ activated Y3Al2Ga3O12 Phosphors and Transparent Phosphor-inGlass. J. Mater. Chem. C 2016, 4, 11457-11464.


32

Page 33 of 35 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(63) Zhang, R.; Lin, H.; Yu, Y.; Chen, D.; Xu, J.; Wang, Y. A New-Generation Color Converter for High-Power White LED: Transparent Ce3+:YAG Phosphor-in-Glass. Laser Photon. Rev. 2014, 8, 158-164. (64) Zheng, P.; Li, S.; Wang, L.; Zhou, T. L.; You, S.; Takeda, T.; Hirosaki, N.; Xie, R. J. Unique Color Converter Architecture Enabling Phosphor-in-Glass (PiG) Films Suitable for High-Power and High-Luminance Laser-Driven White Lighting. ACS Appl. Mater. Interfaces 2018, 10, 14930-14940. (65) Lin, H.; Hu, T.; Cheng, Y.; Chen, M.; Wang, Y. Glass Ceramic Phosphors: Towards LongLifetime High-Power White Light-Emitting-Diode Applications-A Review. Laser Photon. Rev. 2018, 12, 1700344. (66) Xia, Z.; Meijerink, A. Ce3+-Doped Garnet Phosphors: Composition Modification, Luminescence Properties and Applications. Chem. Soc. Rev. 2017, 46, 275-299. (67) Dorenbos, P. Electronic Structure and Optical Properties of the Lanthanide Activated RE3(Al1−xGax)5O12 (RE=Gd, Y, Lu) Garnet Compounds. J. Lumin. 2013, 134, 310-318. (68) Dorenbos, P. Determining Dinding Energies of Valence-Band Electrons in Insulators and Semiconductors Via Lanthanide Spectroscopy. Phys. Rev. B 2013, 87, 87-92. (69) Dorenbos, P. Ce3+ 5d-Centroid Shift and Vacuum Referred 4f-Electron Binding Energies of All Lanthanide Impurities in 150 Different Compounds. J. Lumin. 2013, 135, 93-104. (70) Jia, P. Y.; Lin, J.; Han, X. M.; Yu, M. Pechini Sol–Gel Deposition and Luminescence Properties of Y3Al5−xGaxO12:Ln3+ (Ln3+=Eu3+, Ce3+, Tb3+; 0≤x≤5) Thin Films. Thin Solid Films 2005, 483, 122-129.


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(71) Vrubel, I. I.; Polozkov, R. G.; Shelykh, I. A.; Khanin, V. M.; Rodnyi, P. A.; Ronda, C. R. Bandgap Engineering in Yttrium–Aluminum Garnet with Ga Doping. Cryst. Growth Des. 2017, 17, 1863-1869.


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Table of Contents Graphic


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Tailoring Trap Depth and Emission Wavelength in Y3Al5âxGaxO12

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Tailoring Trap Depth and Emission Wavelength in Y3Al5âxGaxO12