Samarium-doped anatase TiO 2 (A-TiO 2 :Sm) and rutile (R-TiO 2 :Sm) single phase thin films are fabricated by laser ablation and post-annealing at different temperatures. A-TiO 2 :Sm samples exhibit intense PL emission, whilst R-TiO 2 :Sm samples exhibit weak PL emission. The local crystal structure of Sm-dopants is investigated using X-ray absorption fine structure (XAFS) measurements. The thin films showing strong PL emission have lower crystal symmetry than the other samples, which show weak PL emission. We report the relationship between changing the symmetry of the local structure and activation of the luminescent center. The local structure of Sm 3+ thin films annealed at 600˚C to 800˚C, which possess an activated semi-stable Sm 3+ ions luminescent center, dramatically changes from having high symmetry to low symmetry. While the phase transitioned R-TiO 2 :Sm and fabricated as R-TiO 2 :Sm samples showed highly symmetric. Hence, the coordination around the doped-Sm 3+ ions is the key factor for exhibiting an intense PL emission. Therefore, activation of the luminescent center is strongly connected with the distorted local crystal symmetry, which is proposed as one of the factors defining the transfer probability. In this work, we discuss the connection between coordination around Sm 3+ ions and PL intensity, and optical and electrical properties of a n +-ITO/TiO 2 :Sm/p-NiO/p +-Si hetero junction LED preparing with optimal fabricating condition.

Rare earth ions in the oxide semiconductors are commonly surrounded by oxygen (O) ligands which are the first nearest neighbors to rare earths. Intensities of the rare earth-related luminescence are strongly influenced by crystal symmetry of the rare earth ions. Especially, distortion of the first nearest neighbor bonds is key to improving emission from these luminescent centers. In this paper, samarium (Sm) is doped into titanium dioxide (TiO 2 ) with two different crystal structures, anatase and rutile, to investigate the influence of the different host crystal symmetries on the material optical properties. Smrelated photoluminescence (PL) intensity from the samples, annealed at different temperatures reveals the optimal preparation condition. Also, X-ray absorption fine structure (XAFS) spectra are measured, providing detailed information regarding the local fine structure around Sm. From these studies, the authors find that the optical properties of the TiO 2 :Sm are not only influenced by structural changes in the first nearest neighbor, O, but also the second nearest neighbor, Ti by annealing at different temperatures and/or crystal structure of TiO 2 . The authors discuss the connection between the enhanced PL intensity and the local fine structure around the Sm luminescent centers, including these changes in the second nearest neighbor, Ti.

Samarium-doped anatase TiO 2 (A-TiO 2 :Sm) and rutile (R-TiO 2 :Sm) single phase thin films are fabricated by laser ablation and post-annealing at different temperatures. A-TiO 2 :Sm samples exhibit intense PL emission, whilst R-TiO 2 :Sm samples exhibit weak PL emission. The local crystal structure of Sm-dopants is investigated using X-ray absorption fine structure (XAFS) measurements. The thin films showing strong PL emission have lower crystal symmetry than the other samples, which show weak PL emission. We report the relationship between changing the symmetry of the local structure and activation of the luminescent center. The local structure of Sm 3+ thin films annealed at 600˚C to 800˚C, which possess an activated semi-stable Sm 3+ ions luminescent center, dramatically changes from having high symmetry to low symmetry. While the phase transitioned R-TiO 2 :Sm and fabricated as R-TiO 2 :Sm samples showed highly symmetric. Hence, the coordination around the doped-Sm 3+ ions is the key factor for exhibiting an intense PL emission. Therefore, activation of the luminescent center is strongly connected with the distorted local crystal symmetry, which is proposed as one of the factors defining the transfer probability. In this work, we discuss the connection between coordination around Sm 3+ ions and PL intensity, and optical and electrical properties of a n +-ITO/TiO 2 :Sm/p-NiO/p +-Si hetero junction LED preparing with optimal fabricating condition.

Amphiphilic diblock copolymer (PMPC-PBMA) composed of biocompatible water-soluble poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and hydrophobic poly(n-butyl methacrylate) (PBMA) was synthesized via reversible addition-fragmentation chain transfer (RAFT) radical polymerization. Degrees of polymerization for PMPC and PBMA were 95 and 181, respectively. PMPC-PBMA can dissolve in water to form coreshell ellipsoidal polymer micelles. The core of the micelle can incorporate hydrophobic cyanine dye (Cyd) which can absorb light at near infrared (NIR) wavelength. The average hydrodynamic radius (R h) for Cyd-loaded polymer micelles was about 103 nm in water. Exothermic behavior of the aqueous solution can be observed when NIR light irradiates Cyd-loaded polymer micelles in water. It is expected that the Cyd-loaded polymer micelles can be applied to photo thermal therapy (PTT).