Fabrication of phosphor in glass using waste glass for automotive lighting application.

With advancement of technology, requirements for light-emitting devices are increasing. Various types of packaging technologies have been suggested to improve the performance of light-emitting diode (LED). Among them, phosphor in glass (PiG) is attracting attention due to its manufactural facility and easily tunable characteristics. As PiG draws increasing attention, research on glass materials is also being actively conducted. However, studies about glass in the field of phosphor are mainly conducted on fabrication. Only a few studies about recycling have been reported. Thus, the objective of this study was to recycle waste glass discarded in other fields due to breakage and failure and use it to fabricate phosphor in glass. Cylindrical waste glass was pulverized into powder with an average size of 12 µm, mixed with a phosphor and sintered to be reborn as a phosphor in glass to broaden the recycling route for waste glass.

Fabrication of LuAG:Ce3+ Ceramic Phosphors Prepared with Nanophosphors Synthesized by a Sol-Gel-Combustion Method.

The aim of this study was to investigate properties of ceramic phosphors fabricated using nano Lu3Al5O12:Ce3+ phosphors produced with a sol-gel-combustion method. These nano Lu3Al5O12:Ce3+ phosphors had a size of about 200 nm, leading to high density when fabricated as a ceramic phosphor. We manufactured ceramic phosphors through vacuum sintering. Alumina powder was added to improve properties. We mounted the manufactured ceramic phosphor in a high-power laser beam projector and drove it to determine its optical performance. Ceramic phosphor manufactured according to our route will have a significant impact on the laser-driven lighting industry.

Preparation of high-quality YAG:Ce3+ ceramic phosphor by high-frequency induction heated press sintering methods.

This study investigates the characteristics of a ceramic phosphor (CP) for the converter of a high-power laser diode-based automobile headlamp synthesized by high-frequency induction heated press (HFP) sintering. The CP prepared by an HFP method exhibits remarkable optical properties that are comparable to spark plasma sintering. The effects of post-treatment process for controlling residual pores, as well as sintering temperature, sintering pressure and heating rate for optimization of the HFP sintering method, were studied. The HFP sintering process can be widely used in ceramics and lighting fields because it is designed relatively low cost compared to other techniques and exhibits excellent productivity.

Fabrication of Highly Stable Fully-Inorganic Halide Perovskite Films for Optoelectronic Application.

Despite the fact that stability is a critical issue affecting halide perovskite after the materials have been developed, these materials continue to be studied due to their outstanding optoelectronic characteristics such as narrow emission band width, high PLQY. Many methods are suggested and improved, but the limitations for the display and lighting applications are still remaining. Here, we propose the fabrication of stable cesium lead tri-halide (CsPbX3; X= Cl, Br, I) perovskite films using photocurable polyurethane material, norland optical adhesive 63 (NOA 63), to generate white LEDs by placing films on the InGaN 450 nm blue chip. Comparing with the conventional perovskites, fabricated films well maintained the luminescence properties such as full widths at half maximum (FWHM) of 18 nm and 31 nm for green and red films, respectively. For the stability issue, pristine perovskite without encapsulation is decomposed immediately at high humidity and temperature, but NOA 63 encapsulated perovskite maintained a PL emission property of 60% after four hours in artificial atmosphere. The CIE color triangle reached ~119% of the NTSC standard, exhibiting high color purity. From the results, we confirm that the NOA 63 encapsulated halide perovskites are beneficial when applied in optoelectronic applications due to their improved stability and maintained characteristics.

Synthesis and Characterization of Co-Mn (O)OH Nanosheets Assembled Structure Covered of Reduced Graphene Oxide Hybrid Structures by Hydrothermal Method.

In this study, we prepared cobalt-manganese (oxy) hydroxide nanosheets assembled structure covered of reduced graphene oxide hybrid structure (Co-Mn (O)OH NAS@rGO HS) via reduction and hydroxylation of Mn1.5Co1.5[Co(CN)6]2@graphene oxide (GO). Obtained precursors were optimized at 15 mg GO, and these are hybrid structures in which nanocubes 200-400 nm in size were fully covered by multi-layered GO. The functional group (-COOH, -OH, C-O-C) of GO was removed through reduction by L-ascorbic acid. We obtained MnCOOH, Co(OH)2, and Co-Mn LDH synthesized by hydroxylation of Mn1.5Co1.5[Co(CN)6]2@GO via ion exchange between the CN group and OH-. The hybrid nanostructure between transition-metal oxide/hydroxide and reduced graphene oxide could be used in various fields, including lithium ion batteries, supercapacitors, and electrocatalyst for water splitting.

Millerite Core-Nitrogen-Doped Carbon Hollow Shell Structure for Electrochemical Energy Storage.

Nickel sulfides have drawn much attention with the benefits of a high redox activity, high electrical conductivity, low cost, and fabrication ease; however, these metal sulfides are susceptible to mechanical degradation regarding their cycling performance. Conversely, hollow carbon shells exhibit a substantial electrochemical steadiness in energy storage applications. Here, the design and development of a novel millerite core-nitrogen-doped carbon hollow shell (NiS-NC HS) structure for electrochemical energy storage is presented. The nitrogen-doped carbon hollow shell (NC HS) protects against the degradation and the millerite-core aggregation, giving rise to an excellent rate capability and stability during the electrochemical charging-discharging processes, in addition to improving the NiS-NC HS conductivity. The NiS-NC HS/18h supercapacitor electrode displays an outstanding specific capacitance of 1170.72 F g-1 (at 0.5 A g-1 ) and maintains 90.71% (at 6 A g-1 ) of its initial capacitance after 4000 charge-discharge cycles, owing to the unique core-shell structure. An asymmetric-supercapacitor device using NiS-NC HS and activated-carbon electrodes exhibits a high power and energy density with a remarkable cycling stability, maintaining 89.2% of its initial capacitance after 5000 cycles.

Innovatively Continuous Mass Production Couette-taylor Flow: Pure Inorganic Green-Emitting Cs4PbBr6 Perovskite Microcrystal for display technology.

We report for the first time the mass production of Cs4PbBr6 perovskite microcrystal with a Couette-Taylor flow reactor in order to enhance the efficiency of the synthesis reaction. We obtained a pure Cs4PbBr6 perovskite solid within 3 hrs that then realized a high photoluminescence quantum yield (PLQY) of 46%. Furthermore, the Cs4PbBr6 perovskite microcrystal is applied with red emitting K2SiF6 phosphor on a blue-emitting InGaN chip, achieving a high-performance luminescence characteristics of 9.79 lm/W, external quantum efficiency (EQE) of 2.9%, and correlated color temperature (CCT) of 2976 K; therefore, this perovskite is expected to be a promising candidate material for applications in optoelectronic devices.