Yanlin Huang

Bio: Yanlin Huang is an academic researcher from Soochow University (Suzhou). The author has contributed to research in topics: Luminescence & Phosphor. The author has an hindex of 32, co-authored 218 publications receiving 3745 citations. Previous affiliations of Yanlin Huang include Changwon National University & Nantong University.

Luminescence and Microstructural Features of Eu-Activated LiBaPO4 Phosphor

Abstract: Eu2+-activated LiBaPO4 phosphor was synthesized by conventional solid-state reaction. The photoluminescence excitation and emission spectra, the temperature dependent luminescence intensities (12−450 K), and decay curves of the phosphor were investigated. With the increasing of temperatures, the emission bands of LiBaPO4:Eu2+ show the abnormal blue-shift and the decreasing of emission intensity. The natures of the Eu2+ emission in LiBaPO4, for example, the luminescence quenching temperature, and the activation energy for thermal quenching (ΔE), were reported. The afterglow fluorescence was detected in LiBaPO4:Eu2+ phosphor. Together with the Eu2+ luminescence, Eu3+ ions with the abnormal crystal field were observed. The site-selective excitation in the 5D0 → 7F0 region for Eu3+ ions, emission spectra, and decay curves have been investigated using a pulsed, tunable, and narrowband dye laser to detect the microstructure and crystallographic surrounding of Eu3+,2+ at Ba2+ sites in LiBaPO4. The multiple sites...

Optical Thermometry Based on Vibration Sidebands in Y2MgTiO6:Mn4+ Double Perovskite

Abstract: Mn4+-doped Y2MgTiO6 phosphors are synthesized by the traditional solid-state method. Powder X-ray diffraction, scanning electron microscope, and energy-dispersive X-ray spectrometer are employed to...

Luminescence properties and site occupations of Eu3+ ions doped in double phosphates Ca9R(PO4)7 (R = Al, Lu)

Abstract: Eu3+ doped red-emitting phosphors of double phosphates Ca9R(PO4)7 (R = Al, Lu) were synthesized by a general high temperature solid-state reaction. The phosphors were characterized by X-ray powder diffraction (XRD). The detailed luminescence properties, e.g., the emission spectra under the excitation of UV light, the photoluminescence excitation spectra and decay lifetimes were reported. The phosphors can be efficiently excited by near UV light to realize an intense red luminescence (613 nm) corresponding to the electric dipole transition 5D0 → 7F2 of Eu3+ ions. The luminescence properties and the potential applications were analyzed. These phosphors were investigated by the site-selective emission spectra and the fluorescence decay curves in the 5D0 → 7F0 region using a pulsed, tunable, narrowband dye laser. It is suggested that Eu3+ ions have three different crystallographic sites doped in Ca9Al(PO4)7, and five sites in Ca9Lu(PO4)7 host. The site assignments of Eu3+ ions in Ca9R(PO4)7 (R = Al, Lu) were discussed on the base of both optical spectroscopy results and structural analysis.

Thermal stability of luminescence of NaCaPO4?:?Eu2+ phosphor for white-light-emitting diodes

Abstract: A green-emitting phosphor, Eu2+-activated NaCaPO4, was synthesized by the conventional solid-state reaction. The photoluminescence excitation and emission spectra, and the temperature dependence of luminescence intensity of the phosphor were investigated. The results showed that NaCaPO4 : Eu2+ could be efficiently excited by incident light of 280–420 nm, which matched well with the emission wavelengths of near-UV LED chips. NaCaPO4 : Eu2+ has a higher quenching temperature. With an increase in the temperature, the emission bands of NaCaPO4 : Eu2+ show an abnormal blue-shift with broadening bandwidth and decreasing emission intensity. The phosphor has a promising potential for white-light-emitting diodes pumped by ultraviolet chips. The CIE coordinates and luminescence decay (lifetimes) of Eu2+ ions in this monophosphate were discussed in order to further investigate the potential applications.

Abnormal reduction, Eu(3+) → Eu(2+), and defect centers in Eu(3+)-doped pollucite, CsAlSi2O6, prepared in an oxidizing atmosphere.

Abstract: Eu-doped pollucite CsAlSi2O6 was synthesized by the sol-gel method and heated in an air atmosphere. The crystal structure and the microstructure of the phosphors were investigated by X-ray powder diffraction and SEM images, respectively. The photoluminescence spectra and temperature dependent decay curves were measured. An abnormal reduction phenomenon of Eu(3+) → Eu(2+) was reported when Eu(3+) ions were doped in alkaline metal cation sites in CsAlSi2O6 prepared in an oxidizing atmosphere. The abnormal mechanism was discussed on the basis of the charge compensation model and a rigid three-dimensional framework structure of CsAlSi2O6. The luminescence color centers were investigated by luminescence decay lifetimes and thermal stabilities of Eu(2+) ions. The defect complexes of [(Eu(3+)Cs)(••)-2VCs'] or [(Eu(3+)Cs)(••)-Oi″] induced by the substitution of Eu(3+) on Cs(+) were suggested in the lattices. Eu(2+) ions could be regarded as Eu(3+) ions combining with the released electrons from defects Oi″ or VCs' in close vicinity of Eu(3+) (Eu(3+) + e); the electrons cannot enter the atom track of Eu(2+) presenting luminescence of Eu(2+) ions. The results indicate that several defect traps can be attributed to the abnormal reduction mechanism of Eu(3+) to Eu(2+) ions in a matrix.

Long persistent phosphors—from fundamentals to applications

Abstract: Owing to the unique mechanism of photoelectron storage and release, long persistent phosphorescence, also called long persistent luminescence or long lasting afterglow/phosphorescence, plays a pivotal role in the areas of spectroscopy, photochemistry, photonics and materials science. In recent years, more research has focused on the manipulation of the morphology, operational wavebands and persistent duration of long persistent phosphors (LPPs). These desired achievements stimulated the growing interest in designing bio-labels, photocatalysts, optical sensors, detectors and photonic devices. In this review, we present multidisciplinary research on synthetic methods, afterglow mechanisms, characterization techniques, materials system, and applications of LPPs. First, we introduce the recent developments in LPPs for the synthesis of nanoparticles from the aspects of particle sizes, monodispersity and homogeneity based on the urgent application of bio-imaging. In the later sections, we present the possible mechanisms, which involve the variation of trap distribution during the trapping and de-trapping process, complicated photo-ionization reaction of trap site levels and impurity centers together with their corresponding migration kinetics of carriers. Meanwhile, we emphasize the characterization techniques of defects, used to qualitatively or quantitatively describe the types, concentrations and depths of the traps. This review article also highlights the recent advances in suggested LPPs materials with a focus on the LPPs' hosts and optically active centers as well as their control, tuning and intrinsic links. We further discuss the classification of LPPs based on the different emission and excitation wavebands from the ultraviolet to the near-infrared region along with an overview of the activation mode of afterglow. Afterwards, we provide an exhibition of new products towards diverse application fields, including solar energy utilization, bio-imaging, diagnosis, and photocatalysts. Finally, we summarize the current achievements, discuss the problems and provide suggestions for potential future directions in the aforementioned parts.

Lanthanide-Activated Phosphors Based on 4f-5d Optical Transitions: Theoretical and Experimental Aspects.

Abstract: The synthesis of lanthanide-activated phosphors is pertinent to many emerging applications, ranging from high-resolution luminescence imaging to next-generation volumetric full-color display. In particular, the optical processes governed by the 4f-5d transitions of divalent and trivalent lanthanides have been the key to enabling precisely tuned color emission. The fundamental importance of lanthanide-activated phosphors for the physical and biomedical sciences has led to rapid development of novel synthetic methodologies and relevant tools that allow for probing the dynamics of energy transfer processes. Here, we review recent progress in developing methods for preparing lanthanide-activated phosphors, especially those featuring 4f-5d optical transitions. Particular attention will be devoted to two widely studied dopants, Ce3+ and Eu2+. The nature of the 4f-5d transition is examined by combining phenomenological theories with quantum mechanical calculations. An emphasis is placed on the correlation of hos...