Through thermal treatment of a fluoroaluminosilicate glass codoped with Er3+-Yb3+ at a suitable temperature, microcrystallites were successfully precipitated in the glass matrix but little change was observed in the optical transmission spectra even around the ultraviolet edge, meanwhile the green upconversion luminescence due to the 4S3/2-4I15/2 transition of Er3+ increased by a factor of ∼100 when a 0.97 μm laser diode (LD) (5 mW) was used for excitation. The infrared to green or to red upconversion efficiencies for the vitroceramics are evaluated to be nearly 2 or 10 times as high as fluoride glasses, respectively. Also higher mechanical and chemical stabilities and laser damage threshold over fluoride glasses or crystals are expected for the vitroceramics.

Highly efficient infrared-to-visible upconversion has been observed in Er3+-doped BaCl2 phosphors. The composition optimized for maximum green emission was around 25ErCl3 (mol %), which contains 5–15 mol % more active Er3+ ions than those in the conventional Er3+-doped fluoride phosphors. Pumped by a 0.8 μm laser diode with a power density of ∼3 W/cm2, chloride (25ErCl3-75BaCl2) shows a very bright green emission with the intensity being two orders of magnitude larger than that of the commercially available IR sensor card on which an optimized fluoride phosphor Y0.8Er0.2F3 is pasted. A 0.97 μm laser diode excitation on the chloride yielded blue (0.49 μm), green (0.55 μm), and red (0.66 μm) fluorescences, visually exhibited as a bright greenish-white emission. The visible fluorescence excited by 0.8, 0.97, or 1.5 μm laser diodes shows quadratic or cubic dependencies on the excitation power over the entire power range for the chlorides but lower dependences for the fluoride. The differences in the upconversion characteristics between the chlorides and fluoride are discussed in terms of the rate equations and attributed principally to the different Er3+...Er3+ interionic energy transfer probability and the different multiphonon decay rate from the excited states of Er3+ in these matrices.

An organic self-assembled monolayer (SAM) was deposited on submicron-sized pigmentgrade TiO 2 particles to create a highly hydrophilic surface comprised of sulfonate groups. Hydrous aluminum-containing thin films were uniformly deposited on the powder from aqueous solutions at 60-80 °C. The as-deposited films were in the form of boehmite (AlO(OH)) or hydrous Al sulfate, depending on the Al salts used in the starting solution. AlCl 3 solutions gave rise to porous films of needlelike crystalline boehmite, whereas mixed Al 2 (SO 4 ) 3 /Al(NO 3 ) 3 solutions led to compact, uniform, adherent, dense amorphous sulfatecontaining films up to ∼5 nm thick. The sulfate anion in solution is thought to promote nucleation and growth of a solid phase through its relatively strong electrostatic field. However, the sulfate anion is weakly bound, and the sulfate films can be partly leached of sulfur in neutral or weakly basic solutions at room temperature without sacrificing their compact nature.

Bright visible fluorescence was emitted from Er3+-doped halide phosphors and ErX3 (X=Br, I), under 1.5 µm laser diode (5 mW) excitation. While green fluorescence was predominant with chloride ( BaCl2:Er) and bromide ( YBr3:Er), yellowish fluorescence was observed with iodide ( YI3:Er) and fluoride ( YF3:Er). The 550 nm green fluorescence intensities for the chloride, bromide and iodide were, respectively, 43, 10 and 2 times greater than that of conventional fluoride. The excitable wavelength region around 1.5 µm narrowed and the excitation peak shifted toward a longer wavelength with a decrease in the ligand field strength or in the matrix phonon energy.

Two coordination polymers with mixed-ligands, [ZnL(2,2Ј-bipy)H 2 O] n (1) and [CdL(2,2Ј-bipy)] n (2), (Lϭ3,3Ј-thiodipropionic acid; 2, 2Ј-bipyϭ2, 2Ј-bipyridine) have been synthesized and structurally characterized. Crystal structures reveal that the synthesized complexes consist of a one-dimensional singlechain and a one-dimensional double-chain, respectively. A prominent feature of complex 1 is the formation of a vagarious doublechain by two neighboring single-chains interleaving with each other. It is interesting for complex 2 to assemble the double chain into a 2D ordered supramolecular structure via π···π stacking inter-