Ceramic and Crystal Materials for Optics and Photonics: Session I
Sponsored by: ACerS Basic Science Division, ACerS Glass & Optical Materials Division
Program Organizers: Yiquan Wu, Alfred University; Jas Sanghera, Naval Research Laboratory; Akio Ikesue, World-Lab. Co., Ltd; Mark Dubinskiy, Army Research Laboratory; Xiang Hua Zhang, University of Rennes - and - Materials Science Department, University of Arizona; Michael Squillante, Radiation Monitoring Devices Inc; Long Zhang, Shanghai Institute of Optical and Fine Mechanics, Chinese Academy of Science; Takunori Taira, National Institutes of Natural Science

Wednesday 8:00 AM
November 4, 2020
Room: Virtual Meeting Room 15
Location: MS&T Virtual


8:00 AM  Invited
Manipulating Properties via Grain Size Engineering in Transparent Ceramics: James Wollmershauser1; Boris Feigelson1; Lukasz Kuna2; John Mangeri3; Kevin Anderson4; Heonjune Ryou1; Eric Patterson1; Edward Gorzkowski1; Serge Nakhmanson2; 1U.S. Naval Research Laboratory; 2University of Connecticut; 3Academy of Sciences of the Czech Republic; 4National Research Council Postdoctoral Research Fellow sited at U.S. Naval Research Laboratory
    Mechanical property improvements achieved in ceramics by reducing the grain size of bulk dense polycrystalline components is a well-known phenomenon called the Hall-Petch relationship. Recent advances in ceramic sintering processing has allowed the opportunity to explore the limits of those property improvements and re-evaluate other grain size dependent phenomena, such as optical transmission, thermal conductivity, and dielectric properties. In some cases, properties improvements can be extreme, but only evident at the nanoscale – grain sizes below ~100 nm. In other cases, property changes can be minimal supporting that the underlying mechanisms are grain size agnostic. Interestingly, modeling of overlapping phenomena in some special cases, such as piezoelectric optical ceramics, indicate the possibility to modulate properties with an externally applied stimulus. This talk will cover recent work in the literature, at NRL, and with NRL collaborators on grain size dependent properties relevant to optical ceramics.

8:40 AM  Invited
ZnS:Ag Scintillators: Synthesis, Microstructure, and Luminescence: Luiz Jacobsohn1; 1Clemson University
    The goal of this research is the development of a reactive ultrafiltration membrane scintillator for rapid activity determination and isotopic quantification of waterborne special nuclear materials (SNM) to allow for fast forensics analysis of debris from a nuclear event. ZnS:Ag is the best scintillator for the detection of alpha particles that compose the decay of SNM. ZnS:Ag was prepared by the solid state and hydrothermal reaction methods, and characterized on their structure, morphology, luminescence, and scintillation by XRD, Raman scattering, SEM, TEM, photoluminescence, and radioluminescence under X-ray excitation, respectively. For both synthesis methods, luminescence output was maximized at ~0.1-0.2mol% doping. Overall, crystallite size and dominant luminescence emission could be tuned by the synthesis conditions, namely reaction temperature, time, and pH. Co-doping with Al showed significant enhancement of luminescence and scintillation output. Preliminary tests with ZnS:Ag loaded membranes were executed. This work was supported by DTRA under contract HDTRA 1-16-1-0016.

9:00 AM  Invited
Plate/Powder Form of Single Crystal Phosphors for High-brightness White Lighting: Kiyoshi Shimamura1; Encarnacion Garcia Villora1; Daisuke Inomata2; 1National Institute for Materials Science; 2Tamura Corporation
    Single-crystal phosphors (SCPs), which exhibit a superior conversion efficiency, a high thermal stability and a low temperature increase under high-power irradiation, are proposed for high brightness (HB) white lighting applications. SCPs possess a high purity and crystalline quality, thus guarantying best performance in either bulk or powder form. The best yellow phosphor for white LEDs is Ce:YAG, and its emission can be tuned towards the green by Lu substitution. SCPs exhibit an outstanding internal quantum efficiency (QE); at room temperature it’s over 95%, and with the temperature rise it increases even further, reaching a maximum at about 250oC. Instead, the internal QE of CPPs even quenches at much lower temperatures, indicating the presence of undesired non-radiative recombination paths. These show that, SCPs meet the fundamental requirements for emerging HB applications such as laser headlights and laser projectors. Binder-free SCP powder plate is demonstrated, and it has shown the same performance.

9:20 AM  Invited
Nano-phosphor Materials Synthesized by Novel Soft Chemistry, Water-assisted Solid-state Reaction Method: Kenji Toda1; Dae-Ho Yoon2; 1Niigata University; 2Sungkyunkwan University
     We disclose a novel low temperature synthetic technique (water-assisted solid state reaction (WASSR)) for the nano-phosphor materials. The WASSR method is a very simple and can synthesize the nano phosphor materials just by mixing or storing of raw materials with a small amount of water at low temperature (below 573 K). Typical particle sizes (under 20 nm) of the samples prepared by the WASSR method were smaller than that (1 - 10 micrometer size) of the sample prepared by the conventional solid-state reaction method.For example, a stoichiometric mixture of CsCl and PbCl2 was mixed for the WASSR synthesis of perovskite CsPbCl3 quantum dot phosphor. Then, a small amount (10 wt%) of water was added to the mixture and mixed using mortar for 1 min to synthesize a single phase of CsPbCl3. The XRD pattern of the products are in good agreement with that of single phase CsPbCl3.

9:40 AM  
Fabrication and Optical Properties of Yb-doped MgO Transparent Ceramics by Spark Plasma Sintering: Xuan Chen1; David Carloni1; Yiquan Wu1; 1Alfred University
    Yb-doped (0, 0.02, 0.1 and 0.5%) MgO transparent ceramics are synthesized by using spark plasma sintering at relatively low temperature 1100°C for 5 – 60 min under a pressure of 105 MPa. The effects of dopant concentrations and sintering holding times on the densification and microstructure evolution of MgO transparent ceramics are investigated. The 0.02 % Yb-doped MgO ceramic sintered at 1100 °C for 60 min demonstrated the highest in-line transmittance, which is close to that of MgO single crystals. Yb dopant helps improve the transmittance and control the grain growth. The mechanism for the difference in phase and microstructure is studied. Photoluminescence and optical properties of the Yb-doped MgO transparent ceramics are investigated.

10:00 AM  
Investigation Into Improving Scintillation Properties of Cesium Hafnium Chloride: Cordell Delzer1; Ketaki Joshi1; Luis Stand1; Nerine Cherepy2; Steve Payne2; Xianfei Wen1; Jason Hayward1; 1University of Tennessee; 2LLNL
    Scintillators remain an important and large part of our toolbox for use in detection, identification, and localization of potential radiological or nuclear threats. For this application, users desire to have a high density, high-Z, high light yield, non-hygroscopic, and high energy resolution scintillator. One possible candidate is cesium hafnium chloride (CHC). This material shows the potential to outperform NaI(Tl) in all of said criteria. Due to its cubic structure allowing for fast growth, it has the potential to be cheaper than other high performance scintillators like strontium Iodide or lanthanum bromide. So far, CHC crystals of sizes larger than a cubic centimeter have still not shown performance equal to that of the best smaller crystals. In this work, we investigate ways to improve CHC performance as a larger volume scintillator, as well as CHC’s dual mode detection and potential self-calibration capabilities.