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1.
Shifeng Zhou Chaoyu Li Guang Yang Gang Bi Beibei Xu Zhanglian Hong Kiyotaka Miura Kazuyuki Hirao Jianrong Qiu 《Advanced functional materials》2013,23(43):5436-5443
The construction of semiconductor nanocrystal (SNC)‐based composites is of fundamental importance for various applications, including telecommunication, lasers, photovoltaics, and spintronics. The major challenges are the intentional insertion of dopants into SNCs for expanding their intrinsic functionalities and the scalable incorporation of activated SNCs into host free of hydroxyl and organic species for stabilizing and integrating their performances. An in situ approach is presented to couple the SNC doping and loading processes through self‐limiting nanocrystallization of glassy phase, enabling one‐step construction of fully transparent Ga2O3 SNC–glass nanocomposites. It is shown that the intentional introduction of various cation/anion impurities (e.g., F?, In3+, and Ni2+) or their combinations into Ga2O3 SNCs can be realized by taking advantage of the viscous glass matrix to enhance the desorption barrier of impurity on the SNC surface and strengthen its tendency to incorporate into the SNC lattice. The composite can be rationally activated to show wavelength‐tunable and broadband luminescence covering the spectral ranges of near ultraviolet, visible, and near‐infrared wavebands. The approach is predicted to be general to other SNC materials for functional modulations and will be promising for scalable fabrication of novel SNC‐based composites. 相似文献
2.
Zhen Wang Peng Wang Fang Wang Jiafu Ye Ting He Feng Wu Meng Peng Peisong Wu Yunfeng Chen Fang Zhong Runzhang Xie Zhuangzhuang Cui Liang Shen Qinghua Zhang Lin Gu Man Luo Yang Wang Huawei Chen Peng Zhou Anlian Pan Xiaohao Zhou Lili Zhang Weida Hu 《Advanced functional materials》2020,30(5)
2D layered materials are an emerging class of low‐dimensional materials with unique physical and structural properties and extensive applications from novel nanoelectronics to multifunctional optoelectronics. However, the widely investigated 2D materials are strongly limited in high‐performance electronics and ultrabroadband photodetectors by their intrinsic weaknesses. Exploring the new and narrow bandgap 2D materials is very imminent and fundamental. A narrow‐bandgap noble metal dichalcogenide (PtS2) is demonstrated in this study. The few‐layer PtS2 field‐effect transistor exhibits excellent electronic mobility exceeding 62.5 cm2 V?1 s?1 and ultrahigh on/off ratio over 106 at room temperature. The temperature‐dependent conductance and mobility of few‐layer PtS2 transistors show a direct metal‐to‐insulator transition and carrier scattering mechanisms, respectively. Remarkably, 2D PtS2 photodetectors with broadband photodetection from visible to mid‐infrared and a fast photoresponse time of 175 µs at 830 nm illumination for the first time are obtained at room temperature. Our work opens an avenue for 2D noble‐metal dichalcogenides to be applied in high‐performance electronic and mid‐infrared optoelectronic devices. 相似文献
3.
Shifeng Zhou Nan Jiang Bin Zhu Hucheng Yang Song Ye Gandham Lakshminarayana Jianhua Hao Jianrong Qiu 《Advanced functional materials》2008,18(9):1407-1413
Ultra‐broadband luminescent sources that emit light over an extremely wide wavelength range are of great interest in the fields of photonics, medical treatment, and precision measurement. Extensive research has been conducted on materials doped with rare‐earth and transition‐metal ions, but the goal of fabricating an ultra‐broadband emitter has not been attained. We present a facile method to realize this kind of novel light source by stabilizing “active” centers (bismuth) in a “tolerant” host (nanoporous silica glass). The obtained highly transparent materials, in which, unusually, multiple bismuth centers (Bi+, Bi2+, and Bi3+) can be stabilized, emit in an ultra‐broadband wavelength range from blue‐green, orange, red, and white to the near‐infrared region. This tunable luminescence covers the spectral range of the traditional three primary colors (RGB) and also the telecommunications windows. 相似文献
4.
Qiuhong Min Jing Lei Xin Guo Ting Wang Qihua Yang Dacheng Zhou Xue Yu Siu Fung Yu Jianbei Qiu Qiuqiang Zhan Xuhui Xu 《Advanced functional materials》2020,30(6)
Lanthanide‐doped upconversion nanoparticles (UCNPs) have significant applications for single‐molecule probes and high‐resolution display. However, one of their major hurdles is the weak luminescence, and this remains a grand challenge to achieve at the single‐particle level. Here, 484‐fold luminescence enhancement in LuF3:Yb3+, Er3+ rhombic flake UCNPs is achieved, thanks to the Yb3+‐mediated local photothermal effect, and their original morphology, size, and good dispersibility are well preserved. These data show that the surface atomic structure of UCNPs as well as transfer from amorphous to ordered crystal structure is modulated by making use of the local photothermal conversion that is generated by the directional absorption of 980 nm light by Yb3+ ions. The confocal luminescence images obtained by super‐resolution stimulated emission depletion also show the great enhancement of individual LuF3:Yb3+, Er3+ nanoparticles; the high signal‐to‐noise ratio images indicate that the laser treatment technology opens the door for single particle imaging and practical application. 相似文献
5.
Fan Yang Artiom Skripka Antonio Benayas Xianke Dong Sung Hwa Hong Fuqiang Ren Jung Kwon Oh Xinyu Liu Fiorenzo Vetrone Dongling Ma 《Advanced functional materials》2018,28(11)
The combination of biocompatible superparamagnetic and photoluminescent nanoparticles (NPs) is intensively studied as highly promising multifunctional (magnetic confinement and targeting, imaging, etc.) tools in biomedical applications. However, most of these hybrid NPs exhibit low signal contrast and shallow tissue penetration for optical imaging due to tissue‐induced optical extinction and autofluorescence, since in many cases, their photoluminescent components emit in the visible spectral range. Yet, the search for multifunctional NPs suitable for high photoluminescence signal‐to‐noise ratio, deep‐tissue imaging is still ongoing. Herein, a biocompatible core/shell/shell sandwich structured Fe3O4@SiO2@NaYF4:Nd3+ nanoplatform possessing excellent superparamagnetic and near‐infrared (excitation) to near‐infrared (emission), i.e., NIR‐to‐NIR photoluminescence properties is developed. They can be rapidly magnetically confined, allowing the NIR photoluminescence signal to be detected through a tissue as thick as 13 mm, accompanied by high T2 relaxivity in magnetic resonance imaging. The fact that both the excitation and emission wavelengths of these NPs are in the optically transparent biological windows, along with excellent photostability, fast magnetic response, significant T2‐contrast enhancement, and negligible cytotoxicity, makes them extremely promising for use in high‐resolution, deep‐tissue dual‐mode (optical and magnetic resonance) in vivo imaging and magnetic‐driven applications. 相似文献
6.
L.‐N. Sun H.‐J. Zhang L.‐S. Fu F.‐Y. Liu Q.‐G. Meng C.‐Y. Peng J.‐B. Yu 《Advanced functional materials》2005,15(6):1041-1048
The crystal structure of a ternary Er(DBM)3phen complex (DBM = dibenzoylmethane; phen = 1,10‐phenanthroline) and its in‐situ synthesis via a sol–gel process are reported. The infrared (IR), diffuse reflectance (DR), and fluorescence spectra of the pure complex and the Er3+/DBM/phen co‐doped luminescent hybrid gel, formed via an in‐situ method (ErDP gel), have been investigated. The results reveal that the erbium complex is successfully synthesized in situ in the ErDP gel. Excitation at the maximum absorption wavelength of the ligands resulted in the typical near‐IR luminescence (centered at around 1.54 μm) resulting from the 4I13/2 → 4I15/2 transition of the Er3+ ion, which contributes to the efficient energy transfer from the ligands to the Er3+ ion in both the Er(DBM)3phen complex and the ErDP gel (an antenna effect). The full width at half maximum (FWHM) centered at 1541 nm in the emission spectrum of the ErDP gel is 72 nm, which has potential for optical‐amplification applications. Further theoretical analysis on the Er3+ ion in the ErDP gel shows that it appears to be a promising candidate for tunable lasers and planar optical amplifiers. 相似文献
7.
Pengyan Wu Jian Wang Yaming Li Cheng He Zhong Xie Chunying Duan 《Advanced functional materials》2011,21(14):2788-2794
A multifunctional lanthanide‐organic framework Tb? TCA (H3TCA = tricarboxytriphenylamine) comprising a triphenylamine moiety as an efficient luminescence sensitizer is synthesized by a solvothermal method and structurally characterized. Tb? TCA exhibits lanthanide‐based emission (540 nm) and triphenylamine emission (435 nm) after excitation at 350 nm and works as a luminescent chemosensor towards salicylaldehyde with a sensitivity of 10 ppm under optimized conditions. Tb? TCA features a high concentration of Lewis acid Tb3+ sites and Lewis base triphenylamine sites on its internal surfaces; it thus enables both Knoevenagel and cyanosilylation reactions in a size‐selective fashion. The ratiometric fluorescent response towards aldehydes (I540/I435) demonstrates that the absorption of the porous material is size selective, and the interactions between the aldehyde molecules and the Tb3+ ions play a dominant role in the absorption and activation of the aldehyde substrates. In particular, these studies provide opportunities to directly validate the sorption sites and the catalytic mechanism of the multifunctional Ln metal–organic framework material by luminescence. 相似文献
8.
Fiorenzo Vetrone Rafik Naccache Venkataramanan Mahalingam Christopher G. Morgan John A. Capobianco 《Advanced functional materials》2009,19(18):2924-2929
Nanoparticles of NaGdF4 doped with trivalent erbium (Er3+) and ytterbium (Yb3+) are prepared by a modified thermal decomposition synthesis from trifluoroacetate precursors in 1‐octadecene and oleic acid. The nanoparticles emit visible upconverted luminescence on excitation with near‐infrared light. To minimize quenching of this luminescence by surface defects and surface‐associated ligands, the nanoparticles are coated with a shell of NaGdF4. The intensity of the upconversion luminescence is compared for nanoparticles that were coated with an undoped shell (inert shell) and similar particles coated with a Yb3+‐doped shell (active shell). Luminescence is also measured for nanoparticles lacking the shell (core only), and doped with Yb3+ at levels corresponding to the doped and undoped core/shell materials respectively. Upconversion luminescence was more intense for the core/shell materials than for the uncoated nanoparticles, and is greatest for the materials having the “active” doped shell. Increasing the Yb3+ concentration in the “core‐only” nanoparticles decreases the upconversion luminescence intensity. The processes responsible for the upconversion are presented and the potential advantages of “active‐core”/“active‐shell” nanoparticles are discussed. 相似文献
9.
Solution‐Processable Near‐Infrared–Responsive Composite of Perovskite Nanowires and Photon‐Upconversion Nanoparticles
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Bingxiao Yang Yangbo Wang Tian Wei Yue Pan Enlong Zhou Ze Yuan Yingdong Han Mengxue Li Xincan Ling Lisha Yin Xiaoji Xie Ling Huang 《Advanced functional materials》2018,28(31)
Organolead halide perovskites (OHPs) have shown unprecedented potentials in optoelectronics. However, the inherent large bandgap has restrained its working wavelength within 280–800 nm, while light at other regions, e.g., near‐infrared (NIR), may cause drastic thermal heating effect that goes against the duration of OHP devices, if not properly exploited. Herein, a solution processable and large‐scale synthesis of multifunctional OHP composites containing lanthanide‐doped upconversion nanoparticles (UCNPs) is reported. Upon NIR illumination, the upconverted photons from UCNPs at 520–550 nm can be efficiently absorbed by closely surrounded OHP nanowires (NWs) and photocurrent is subsequently generated. The narrow full width at half maximum of the absorption of rare earth ions (Yb3+ and Er3+) has ensured high‐selective NIR response. Lifetime characterizations have suggested that Förster resonance energy transfer with an efficiency of 28.5% should be responsible for the direct energy transfer from UCNPs to OHP NWs. The fabricated proof‐of‐concept device has showcased perfect response to NIR light at 980 and 1532 nm, which has paved new avenues for applications of such composites in remote control, distance measurement, and stealth materials. 相似文献
10.
Although remarkable progress on luminescent materials is made in advanced optical information storage and anti-counterfeiting applications, many challenges still remain in these fields. Currently, most luminescent materials are based on a single photoluminescent model that can be easily imitated by substitutes. In this work, a series of multimodal emission lanthanide-based metal–organic frameworks (MOFs) are developed, where they emit red and green light originating from Eu3+ and Tb3+ under ultraviolet light irradiation. Meanwhile, under 980 nm near-infrared laser irradiation, these MOFs show cyan upconversion cooperative luminescence derived from Yb3+ and characteristic upconversion luminescence from lanthanide activators (Eu3+, Tb3+, or Ho3+), respectively. Based on the integrated optical functionality, the functional information storage applications are successfully designed, which indicates that multimodal emission features can be easily detected under ultraviolet lamps (254 or 393 nm) or 980 nm near-infrared laser. And, the unique optical features show a high level of security in the advanced information storage application, which would be sufficiently complex to be forged. 相似文献
11.
Yichao Wang Takatoshi Seto Kento Ishigaki Yoshiya Uwatoko Guanjun Xiao Bo Zou Guangshe Li Zuobin Tang Zebin Li Yuhua Wang 《Advanced functional materials》2020,30(34)
A series of BaLi2Al2Si2N6 (BLASN): xEu2+ phosphors are successfully synthesized and their crystal structure and luminescence properties under varying hydrostatic pressures are reported herein. Structure variation is analyzed using in situ high‐pressure X‐ray diffraction and Rietveld refinements. Based on decay curves and Gaussian fitting of emission spectra, the presence of two photoluminescence centers is demonstrated. BaLi2Al2Si2N6: 0.01Eu2+ exhibits an evident peak position shift from 532 to 567 nm with an increase in pressure to ≈20 GPa. The possible factors and mechanisms for the variations are studied in detail. At a pressure of 16 GPa, BLASN: Eu2+ realizes a narrow yellow emission with a full width at half maximum of ≈70 nm. The addition of BLASN: Eu2+ (16 GPa) to the commercial white light‐emitting diodes combination consisting of an InGaN chip, β‐SiAlON: Eu2+, and red K2SiF6:Mn4+, can increase the color gamut by ≈15%, demonstrating the promising potential of pressure‐driven BLASN: Eu2+ for wide‐color gamut spectroscopy applications. Moreover, the emission shifts arising from pressure variation and the distinct color changes enable its potential utility as an optical pressure sensor; the material exhibits high pressure sensitivity (dλ/dP ≈ 1.58 nm GPa?1) with the advantage of visualization. 相似文献
12.
T. Jüstel D. U. Wiechert C. Lau D. Sendor U. Kynast 《Advanced functional materials》2001,11(2):105-110
The optical properties of Tb3+/Ce3+ doped zeolites are elucidated with emphasis on ultraviolet (UV) and vacuum ultraviolet (VUV) excitation and luminescence. Ce3+ sensitized Tb3+ emission with quantum yields of 85 % may be obtained at 330 nm excitation. Low absorptivity at 254 nm due to low Ce3+ concentrations or low Ce3+/Tb3+ ratios, which are required for the suppression of UV components, restricts their applicability as phosphors for Hg‐based discharges, e.g., in conventional fluorescent lamps. Near band edge excitation at 172 nm revealed an immediate quantum yield of 50 % enabled by a zeolite → Ce3+ (5d1) → Tb3+ (4f75d1) energy transfer channel, which may be exploited for the down‐conversion of the Xe2 excimer emission. 相似文献
13.
Shili Gai Piaoping Yang Chunxia Li Wenxin Wang Yunlu Dai Na Niu Jun Lin 《Advanced functional materials》2010,20(7):1166-1172
The synthesis (by a facile two‐step sol–gel process), characterization, and application in controlled drug release is reported for monodisperse core–shell‐structured Fe3O4@nSiO2@mSiO2@NaYF4: Yb3+, Er3+/Tm3+ nanocomposites with mesoporous, up‐conversion luminescent, and magnetic properties. The nanocomposites show typical ordered mesoporous characteristics and a monodisperse spherical morphology with narrow size distribution (around 80 nm). In addition, they exhibit high magnetization (38.0 emu g?1, thus it is possible for drug targeting under a foreign magnetic field) and unique up‐conversion emission (green for Yb3+/Er3+ and blue for Yb3+/Tm3+) under 980 nm laser excitation even after loading with drug molecules. Drug release tests suggest that the multifunctional nanocomposites have a controlled drug release property. Interestingly, the up‐conversion emission intensity of the multifunctional carrier increases with the released amount of model drug, thus allowing the release process to be monitored and tracked by the change of photoluminescence intensity. This composite can act as a multifunctional drug carrier system, which can realize the targeting and monitoring of drugs simultaneously. 相似文献
14.
Neuroendocrine Tumor‐Targeted Upconversion Nanoparticle‐Based Micelles for Simultaneous NIR‐Controlled Combination Chemotherapy and Photodynamic Therapy,and Fluorescence Imaging
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Guojun Chen Renata Jaskula‐Sztul Corinne R. Esquibel Irene Lou Qifeng Zheng Ajitha Dammalapati April Harrison Kevin W. Eliceiri Weiping Tang Herbert Chen Shaoqin Gong 《Advanced functional materials》2017,27(8)
Although neuroendocrine tumors (NETs) are slow growing, they are frequently metastatic at the time of discovery and no longer amenable to curative surgery, emphasizing the need for the development of other treatments. In this study, multifunctional upconversion nanoparticle (UCNP)‐based theranostic micelles are developed for NET‐targeted and near‐infrared (NIR)‐controlled combination chemotherapy and photodynamic therapy (PDT), and bioimaging. The theranostic micelle is formed by individual UCNP functionalized with light‐sensitive amphiphilic block copolymers poly(4,5‐dimethoxy‐2‐nitrobenzyl methacrylate)‐polyethylene glycol (PNBMA‐PEG) and Rose Bengal (RB) photosensitizers. A hydrophobic anticancer drug, AB3, is loaded into the micelles. The NIR‐activated UCNPs emit multiple luminescence bands, including UV, 540 nm, and 650 nm. The UV peaks overlap with the absorption peak of photocleavable hydrophobic PNBMA segments, triggering a rapid drug release due to the NIR‐induced hydrophobic‐to‐hydrophilic transition of the micelle core and thus enabling NIR‐controlled chemotherapy. RB molecules are activated via luminescence resonance energy transfer to generate 1O2 for NIR‐induced PDT. Meanwhile, the 650 nm emission allows for efficient fluorescence imaging. KE108, a true pansomatostatin nonapeptide, as an NET‐targeting ligand, drastically increases the tumoral uptake of the micelles. Intravenously injected AB3‐loaded UCNP‐based micelles conjugated with RB and KE108—enabling NET‐targeted combination chemotherapy and PDT—induce the best antitumor efficacy. 相似文献
15.
Pattarawadee Therdkatanyuphong Pongsakorn Chasing Chokchai Kaiyasuan Sumita Boonnab Taweesak Sudyoadsuk Vinich Promarak 《Advanced functional materials》2020,30(31)
Many efforts have been dedicated to developing near infrared (NIR) fluorescent emitters with strong emission especially in the range of 700–1000 nm due to their potential applications in biomedical and optoelectronic fields. However, high solid state NIR emission fluorophores are still rare for applications. Herein, two efficient donor‐π‐acceptor type NIR emitters, C3HTP and C4HTP , are designed and synthesized by end‐capping two isomeric bis(n‐hexylthienyl)thiadiazole[3,4‐c]pyridines as π‐acceptor with structural bulky, electron rich tercarbazole moiety. They exhibit excellent solid state NIR emission with an emission peak at 725 nm, especially C3HTP , reaching a record high photoluminescence quantum yield (ΦPL) of 34% for NIR organic fluorescent materials. By taking advantage of their ΦPL values in the film state (ΦPL = 10–34%), suitable energy levels (highest occupied molecular orbital (HOMO) level ≈ ?5.3 eV), high hole mobility (5.49 × 10?8 cm2 V?1 s?1) as well as good amorphous film forming ability by solution casting, they are used to fabricate a nondoped emissive layer (EML) in simple double‐layer solution processed NIR electroluminescent (EL) devices. The device containing C3HTP as the EML shows a NIR emission peaking at 726 nm and excellent EL performance with a high external quantum efficiency of 1.51%, which is the best solution processed nondoped NIR organic light‐emitting diodes reported to date. Importantly, this represents an advance in near infrared organic fluorescent materials and EL devices that meet the requirements of many applications. 相似文献
16.
Yang Xiang Xue‐Feng Yu Ding‐Fei He Zhengbo Sun Zhijian Cao Qu‐Quan Wang 《Advanced functional materials》2011,21(22):4388-4396
The discovery of new lanthanide properties in layered rare‐earth hydroxides is tremendously important to developing novel materials with the advantages of both lanthanides and layered hydroxides. Herein, a polyethylenimine‐assisted hydrothermal route for preparing Ce‐doped layered yttrium hydroxide nanoplates (LYH:Ce NPs) is established, in which the Ce doping provides simultaneous control of the size and fluorescent properties. Typically, 10% Ce doping tailors the average particle size from 680 to 196 nm and induces bright blue luminescence with a quantum efficiency of over 10.0%. Owing to the much more efficient f–d Ce3+ transition, the LYH:Ce NPs show three orders of magnitude stronger photoluminescence than LYH:Eu and LYH:Tb NPs, and exhibit the properties required to fabricate switched “on/off” optical sensors by controlling the Ce3+ ? Ce4+ redox couple. Furthermore, by combining the merits of the luminescence of Ce3+ dopants and anion‐exchange ability of an LYH host, the LYH:Ce NPs exhibit the properties necessary for photofunctional materials for photosensitized singlet oxygen production. 相似文献
17.
Nanocrystalline Ln3+‐doped YF3 phosphors have been synthesized via a facile sonochemistry‐assisted hydrothermal route. YF3 nanoparticles are demonstrated to be a good host material for different lanthanides. Varying the dopants leads to different optical properties. In particular, the feasibility of inducing red, green, and especially blue emission in the Yb3+/Er3+ co‐doped YF3 sample by up‐conversion excitation in the near‐infrared region is demonstrated. Such unusually strong 411 nm blue up‐conversion emission has seldom been reported in other Yb3+/Er3+‐doped systems. The up‐conversion mechanisms have been analyzed. 相似文献
18.
An O2 Self‐Supplementing and Reactive‐Oxygen‐Species‐Circulating Amplified Nanoplatform via H2O/H2O2 Splitting for Tumor Imaging and Photodynamic Therapy
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Chi Zhang Wei‐Hai Chen Li‐Han Liu Wen‐Xiu Qiu Wu‐Yang Yu Xian‐Zheng Zhang 《Advanced functional materials》2017,27(43)
Conventional photodynamic therapy (PDT) has limited applications in clinical cancer therapy due to the insufficient O2 supply, inefficient reactive oxygen species (ROS) generation, and low penetration depth of light. In this work, a multifunctional nanoplatform, upconversion nanoparticles (UCNPs)@TiO2@MnO2 core/shell/sheet nanocomposites (UTMs), is designed and constructed to overcome these drawbacks by generating O2 in situ, amplifying the content of singlet oxygen (1O2) and hydroxyl radical (?OH) via water‐splitting, and utilizing 980 nm near‐infrared (NIR) light to increase penetration depth. Once UTMs are accumulated at tumor site, intracellular H2O2 is catalyzed by MnO2 nanosheets to generate O2 for improving oxygen‐dependent PDT. Simultaneously, with the decomposition of MnO2 nanosheets and 980 nm NIR irradiation, UCNPs can efficiently convert NIR to ultraviolet light to activate TiO2 and generate toxic ROS for deep tumor therapy. In addition, UCNPs and decomposed Mn2+ can be used for further upconversion luminescence and magnetic resonance imaging in tumor site. Both in vitro and in vivo experiments demonstrate that this nanoplatform can significantly improve PDT efficiency with tumor imaging capability, which will find great potential in the fight against tumor. 相似文献
19.
1.6 µm emission originated from Pr3+: (3F3, 3F4) → 3H4 transition in Pr3+‐ and Pr3+/Er3+‐doped selenide glasses was investigated under an optical pump of a conventional 1480 nm laser diode. The measured peak wavelength and full‐width at half‐maximum of the fluorescent emission are ~1650 nm and ~120 nm, respectively. A moderate lifetime of the thermally coupled upper manifolds of ~212 ± 10 µs together with a high stimulated emission cross‐section of ~(3 ± 1)×10??20 cm2 promises to be useful for 1.6 µm band fiber‐optic amplifiers that can be pumped with an existing high‐power 1480 nm laser diode. Codoping Er3+ enhances the emission intensity by way of a nonradiative Er3+: 4I13/2 → Pr3+: (3F3, 3F4) energy transfer. The Dexter model based on the spectral overlap between donor emission and acceptor absorption describes well the energy transfer from Er3+ to Pr3+ in these glasses. Also discussed in this paper are major transmission loss mechanisms of a selenide glass optical fiber. 相似文献
20.
Zhiyu Yang Yifei Zhao Yayun Zhou Jianwei Qiao Yu-Chun Chuang Maxim S. Molokeev Zhiguo Xia 《Advanced functional materials》2022,32(1):2103927
Near-infrared (NIR) light-emitting diodes (LEDs) light sources are desirable in photonic, optoelectronic, and biological applications. However, developing broadband red and NIR-emitting phosphors with good thermal stability is always a challenge. Herein, the synthesis of Eu2+-activated SrY2O4 red phosphor with high photoluminescence quantum efficiency and broad emission band ranging from 540 to 770 nm and peaking at 620 nm under 450 nm excitation is designed. Sr/Ba substitution in SrY2O4:Eu2+ has been further utilized to achieve tunable emission by modifying the local environment, which facilitates the giant red-shifted emission from 620 to 773 nm while maintaining the outstanding thermal stability of SrY2O4:Eu2+. The NIR emission is attributed to the enhanced Stokes shift and crystal field strength originated from the local structural distortions of [Y1/Eu1O6] and [Y2/Eu2O6]. The investigation in charge distribution around Y/Eu provides additional insight into increasing covalency to tune the emission toward the NIR region. As-fabricated NIR phosphor-converted LEDs demonstration shows its potential in night-vision technologies. This study reveals the NIR luminescence mechanism of Eu2+ in oxide-based hosts and provides a design principle for exploiting Eu2+-doped NIR phosphors with good thermal stability. 相似文献