Tsung-Yuan Chang

Biologically inspired flexible quasi-single-mode random laser: An integration of Pieris canidia butterfly wing and semiconductors

Quasi-periodic structures of natural biomaterial membranes have great potentials to serve as resonance cavities to generate ecological friendly optoelectronic devices with low cost. To achieve the first attempt for the illustration of the underlying principle, the Pieris canidia butterfly wing was embedded with ZnO nanoparticles. Quite interestingly, it is found that the bio-inspired quasi-single-mode random laser can be achieved by the assistance of the skeleton of the membrane, in which ZnO nanoparticles act as emitting gain media. Such unique characteristics can be interpreted well by the Fabry-Perot resonance existing in the window-like quasi-periodic structure of butterfly wing. Due to the inherently promising flexibility of butterfly wing membrane, the laser action can still be maintained during the bending process. Our demonstrated approach not only indicates that the natural biological structures can provide effective scattering feedbacks but also pave a new avenue towards designing bio-controlled photonic devices.

Organic–Inorganic Hybrid Zinc Phosphate with 28‐Ring Channels

An organic-inorganic hybrid zinc phosphate with 28-ring channels was synthesized by use of an organic ligand instead of organic amine template under a hydro(solvo)thermal condition. This crystalline zinc phosphate contains large channels constructed from 28 zinc and phosphate tetrahedral units. The walls of the channels consist of two types of zincophosphate chains, in which the Zn atoms are coordinated by 2,4,5-tri(4-pyridyl)-imidazole ligands as pendent groups. This compound exhibits yellow emission and interesting properties of removing cobalt, cadmium, and mercury cations from aqueous solution. A new two-dimensional organic-inorganic hybrid zincophosphate was also obtained by changing the solvent mixture ratios in the synthesis.

New nanostructured zinc phosphite templated by cetyltrimethylammonium cations: synthesis, crystal structure, adsorption, and photoluminescence properties.

Nanostructured zinc phosphite templated by cetyltrimethylammonium (CTA(+)) cations was synthesized using a hydro(solvo)thermal method. This is the first example of a crystalline metal phosphite containing long carbon tails of the CTA(+) ions as templates in its structure, as is structurally characterized by single-crystal X-ray diffraction. The 2D inorganic structures with 4.8(2) topologies are constructed from the interconnection of tetrahedral ZnO3Br and HPO3 units, which are sandwiched between CTA(+) ion surfactants in a packing behavior of a largely lamellar liquid-crystalline structure to extend the interlayer d spacing to 28.05 Å. Adsorption experiment shows selective adsorption properties of 1-naphthol and a adsorption capacity of 0.17 mmol/mmol (CTA)ZnBr(HPO3). This compound has potential as an adsorbent for the removal of 1-naphthol pollutant from wastewater. In addition, the naphthol-adsorbed sample shows interesting luminescent properties that are different from that of an as-synthesized sample. The crystal structure, thermal stability, IR spectrum, adsorption, and photoluminescence properties have been studied.

New 3 D Tubular Porous Structure of an Organic-Zincophosphite Framework with Interesting Gas Adsorption and Luminescence Properties

A new 3D tubular zinc phosphite, Zn2 (C22 H22 N8 )0.5 (HPO3 )2 ⋅H2 O (1), incorporating a tetradentate organic ligand was synthesized under hydro(solvo)thermal conditions and structurally characterized by single-crystal X-ray diffraction. Compound 1 is the first example of inorganic zincophosphite chains being interlinked through 1,2,4,5-tetrakis(imidazol-1-ylmethyl)benzene to form a tubular porous framework with unusual organic-inorganic hybrid channels. The thermal and chemical stabilities, high capacity for CO2 adsorption compared to that for N2 adsorption, and interesting optical properties of LED devices fabricated using this compound were also studied.

Ultraviolet and visible random lasers assisted by diatom frustules

Random laser actions in ultraviolet and visible regions have been demonstrated based on the composites consisting of bio-inspired diatom frustules. Owing to the low optical loss derived from porous network of diatom structures, we report wide spectrum range random lasers arising from GaN film and Rh6G dye via using biological diatoms as scattering centers. Interestingly, both ultraviolet and visible-range random laser actions with very sharp peaks can be easily obtained, with the average length of optics cavity closed to the average size of diatom frustules in both cases, indicating the excellent optical confinement of diatom frustules. It is expected that the first proof of concept shown here can pave an avenue toward future broad-range random lasers and eco-friendly biophotonics devices with high performance and wide spectrum response.

Conversion of Biowaste Asian Hard Clam (Meretrix lusoria) Shells into White-Emitting Phosphors for Use in Neutral White LEDs

The increasing volume and complexity of waste associated with the modern economy poses a serious risk to ecosystems and human health. However, the remanufacturing and recycling of waste into usable products can lead to substantial resource savings. In the present study, clam shell waste was first transformed into pure and well-crystallized single-phase white light-emitting phosphor Ca9Gd(PO4)7:Eu2+,Mn2+ materials. The phosphor Ca9Gd(PO4)7:Eu2+,Mn2+ materials were synthesized by the solid-state reaction method and the carbothermic reduction process, and then characterized and analyzed by means of X-ray diffraction (XRD) and photoluminescence (PL) measurements. The structural and luminescent properties of the phosphors were investigated as well. The PL and quantum efficiency measurements showed that the luminescence properties of clam shell-based phosphors were comparable to that of the chemically derived phosphors. Moreover, white light-emitting diodes were fabricated through the integration of 380 nm chips and single-phase white light-emitting phosphors (Ca0.979Eu0.006Mn0.015)9Gd(PO4)7 into a single package of a white light emitting diode (WLED) emitting a neutral white light of 5298 K with color coordinates of (0.337, 0.344).

Effects of a thermally stable chlorophyll extract from diatom algae on surface textured Si solar cells

We present the effects of a chlorophyll extract from diatom algae as a spin-coating anti-reflection layer on surface textured silicon solar cells. The diatom extract with a refractive index value in-between Si and air can suppress the overall light reflection from the bare Si surface up to 7% over spectral regions of 350–1100 nm. Additionally, it also shows a strong photon downconversion effect within the visible light regime. Based on both optical characteristics, the short circuit current density is largely enhanced for an approximately 10% increment in the cell efficiency. Additionally, the diatom extract is also thermally stable up to 90 °C without apparent color change and any degradation of optical properties. Thus, the presented approach is simple, doable, suitable for large area application, and more importantly, it is eco-friendly.

Preparation and characterization of Eu3+ ion in Mg-substituted tricalcium phosphate phosphors

Photoluminescence investigation of Eu activated Mg-substituted tricalcium phosphate (β-TCMP) phosphors were prepared by solid-state reaction. The structure and emission spectra were well characterized by X-ray diffraction (XRD) and photoluminescence (PL) techniques. The excitation and emission spectra show that all the Eu3+ doped β-TCMP samples can effectively emit the light excited by UV light. The red-emitting β-TCMP:Eu3+ phosphors may be efficient photoluminescent materials for solid-state lighting phosphors.

Quantum confinement effects of Si/SiGe strained-layer superlattices grown by an ultrahigh vacuum/chemical vapor deposition technique

Well-resolved band-edge luminescence is observed for Si0.86Ge0.14/Si strained-layer superlattices grown by an ultrahigh vacuum/chemical vapour deposition technique at 550 ‡C. High-resolution double-crystal X-ray diffraction (HRXRD) and cross-sectional transmission electron microscopy (XTEM) were used to determine the strain and other parameters for these strained-layer superlattices. Quantum confinement is observed for a SiGe well as thin as 1.3 nm. The blue shift of the emission peaks with decreasing well width is found to be in good agreement with theoretical calculation.