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In this paper, the 0.78 eV line of the dislocation related luminescence in the electron-irradiated silicon has been investigated. It is found that the 0.78 eV line only exists in float zone silicon samples, and its intensity could be largely enhanced by high temperature and long time annealing while no 0.78 eV line was found in Czochralski silicon. The activation energy of 0.78 eV line in floating-zone silicon is ∼13 meV, indicating a different nature from that of D1/D2 lines which can be ascribed to specific reconstructed dislocations which could be easily affected by point defects and temperature. [ABSTRACT FROM AUTHOR]

Abstract: Luminescent CuInS2 nanocrystals have been synthesized in dodecanethiol using air-stable precursors. The nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. The optical properties of the CuInS2 nanocrystals can be controlled by changing the reaction conditions, such as reaction time, temperature, and addition of ligands. It was found that the steady-state photoluminescence spectrum of the close-packed CuInS2 nanocrystals on glass substrate peaked at longer wavelength than that of the colloidal ones and the close-packed nanocrystals possessed a shorter luminescence decay time. This behavior was explained on the basis of Förster resonant energy transfer due to the shorter distance between nanocrystals on substrate. [Copyright &y& Elsevier]

Abstract: The pn diodes were fabricated by implanting B ions into n-type Si substrate and followed by annealing at 950°C for 20min. Carrier concentrations of the pn diodes were measured by spreading resistance profile (SRP). The room-temperature photoluminescence (PL) and the microstructures of the defects resulted from the ion-implantation of the pn diodes were investigated. Electron-beam-induced current (EBIC) was measured to detect carrier recombinations at different depth in the pn diode. The enhanced PL line centered at about 1160nm, which is related to band edge radiative recombination, was observed in the implanted sample. It was found that dislocation loops were formed in the p-type region which is above the pn junction. Moreover, there are intense carrier recombinations at the region of dislocation loops. The EBIC results proved that the enhanced luminescence originated from the region of dislocation loops, but not from the dislocation loops themselves. It is believed that the intense band edge luminescence is due to the quantum confinement of dislocation loops. [Copyright &y& Elsevier]

We presented fluorescence spectra and cathode-luminescence spectra of as-prepared porous silicon under different preparation conditions. The luminescence of porous silicon may be related to the luminescent centers on porous silicon surface. The luminescent efficiency depended on the porosity of porous silicon, which further depended on the oxidative level of porous silicon with metal assistance. Under back illumination, the higher the oxidative degree of the metal is, the higher is the porosity and the luminescent efficiency of porous silicon. But under front illumination, the results exhibited an opposite tendency, which can be explained by the formation theory of PS. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, Cathodoluminescence and Photoluminescence in porous silicon prepared by different etching times were reported. The Cathodoluminescence emission may originate from the presence of hydrogen atoms in oxide phase, which is reduced by electron beam irradiation, but the Photoluminescence emission may be associated with the defects in dioxide in porous silicon surface, which can be proved by scanning electron microscopy images, Fourier transform infrared spectra and Raman spectra. Under electron beam irradiation, the degradation of Cathodoluminescence intensity from as-prepared sample is attributed to hydrogen-atom desorption from porous silicon surface or destruction of irradiative center on porous silicon surface. During electron-beam radiation, the stabilization of Cathodoluminescence emission of the samples, which are post treated by electron beam exposure for 60 s and then aged for 2 min, is due to the protection of surface oxidized layer generated from electron beam heating. [Copyright &y& Elsevier]

Abstract: A novel 2D 4·82 CdII network with alternating heterochiral motif was reported, which is extended to 3D through π–π stacking. Interestingly, 1D hydrophilic tunnel of 3D architecture, providing potential helical hydrogen-bonded identification sites, acts as a template for the formation of the alternate left- and right-handed 1D helical water chains. The compound exhibits intense photoluminescence at room temperature. [Copyright &y& Elsevier]

The photoluminescence (PL) from defect-related states and Si nanoclusters was observed in the Si-rich silicon nitride films simultaneously. The weaker red-light emission of Si nanoclusters was obtained in the 1100 °C annealed films with the 514.5 nm excitation. Due to the quantum confinement effect, the PL peaks redshift with the increase of the excess Si concentration. Excited by the 325 nm line, strong PL from N and Si dangling bond centers was observed in either the as-deposited films or the 1100 °C annealed ones. The results demonstrate that the luminescence from defect-related states or Si nanoclusters is selected by the excitation energy. [ABSTRACT FROM AUTHOR]

Abstract: The optical properties of porous silicon (PS) and poly[2-methoxy-5(2′-ethylhexyloxy-p-phenylenevinylene)] (MEH-PPV) polymer composites were investigated. The experiment results showed that the luminescence intensity of the composites was enhanced and the PL peak position was found red shift. The pore structure of PS decreased the collision and increased conjugation of MEH-PPV molecules, which caused the enhanced luminescence of the composites. Also, the reaction between the surface states of PS and MEH-PPV molecules provided a route of non-radiation recombination that then transferred a part of excitation energy of PS to MEH-PPV. And the excitation transfer caused the enhanced luminescence and red shift. [Copyright &y& Elsevier]

A single-component Ca 7 Mg 2 (PO 4) 6 :Dy3+, Eu3+ white-emitting phosphor was synthesized by a sol-gel approach. The effects of the amounts of Dy3+ ions and Eu3+ ions on the luminescence characteristics and crystal structure of Ca 7 Mg 2 (PO 4) 6 :Dy3+, Eu3+ were systematically investigated. The Ca 7 Mg 2 (PO 4) 6 :Dy3+, Eu3+ phosphors had a Ca 7 Mg 2 (PO 4) 6 structure with an R3c (161) space group. The Ca 7 Mg 2 (PO 4) 6 :Dy3+ phosphor showed emission peaks at both 484 nm (blue) and 576 nm (yellow), which led to the realization of white light. Furthermore, after codoping Eu3+ ions into the structure, a red emission peak (∼617 nm) appeared in the spectrum as a supplementary red component. A warm white light with a low correlated colour temperature (CCT) is obtained from Dy3+/Eu3+-codoped Ca 7 Mg 2 (PO 4) 6. The luminescence intensity at 483 K still reaches more than 73 % of that at 303 K. The packaged LEDs display a bright warm white light with CCT value and colour rendering index (CRI) of 3878 K and 86.7, respectively, which is comfortable for the human eye. With excellent luminescence performances, the white-emitting Ca 7 Mg 2 (PO 4) 6 :Dy3+, Eu3+ phosphor had a significant application potential in the w -LED field. [ABSTRACT FROM AUTHOR]

The visible red band light emission of the Si-rich silicon oxide films prepared by electron-beam evaporation with postannealing was investigated. The films annealed at temperatures lower than 600 °C were composed of Si nanoclusters with high fraction of boundary atoms, featuring photoluminescence (PL) band centered at 700–710 nm. By contrast, the PL bands of the films annealed at temperatures higher than 600 °C redshifted with the expansion of the Si nanoclusters. The most intense light emission was observed in the 600 °C annealed sample. The conversion of the luminescence mechanism from surface states controlled to quantum confinement controlled was proposed on the basis of the evolution of the film structure. [ABSTRACT FROM AUTHOR]

Exploiting the chirality transfer and amplification in the hierarchical chiral systems by the visible and accurate structures is still a challenge. Herein, a pair of homochiral metal‐organic frameworks (MOFs) DCF‐12 and LCF‐12 with high rigidity and high porosity are synthesized via reticular chemistry. Interestingly, these two enantiomers can act as nano‐containers, in which four chromophores, covering acridine, pyrene, 9,10‐Bis(phenylvinyl) anthracene (BPEA), and coronene can be introduced by in situ encapsulation. Importantly, the precise single crystal structures of all guest‐loaded MOFs by X‐ray diffraction technique can be obtained smoothly. It not only clearly reveals the chirality transfer from chiral host framework to achiral guest emitters through space chirality transfer, but also circularly polarized luminescence can be achieved and modulated through the synergistic effect. Extraordinarily, both pyrene@DCF‐12 and pyrene@LCF‐12 exhibit fascinating multi‐color tunable room temperature phosphorescence (RTP) and dynamic circularly polarized luminescence. Besides, the RTP quantum yields of pyrene@DCF‐12 and pyrene@LCD‐12 are high up to 75.39% and 73.43%, which exceeds most of that of RTP materials. These results demonstrate that chiral MOFs can serve as an accurate platform to investigate the mechanism of chirality transfer and amplification and to prompt the development of CPL‐active materials. [ABSTRACT FROM AUTHOR]

Silicon based erbium doped Ga 2 O 3 films and devices are fabricated. It is found that the intensity of Er3+ ions emission can be enhanced by optimizing the content of sensitizer as well as increasing the optical activity of Er3+ ions in the way of adjusting the annealing process. The indirectly excited luminescence of Er3+ ions can be improved, as measured by photoluminescence and electroluminescence, via selecting N 2 as the ambient, decreasing the annealing temperature or prolonging the thermal treatment time. Herein, light emitting devices present the maximum optical power density of ∼0.84 μW/cm2. This work proposes a way to optimize the indirect emission by regulating the content of sensitizers and the optical activity of Er3+ ions, beneficial to the practical use of electrically-driven silicon-based light sources. • Er doped Ga 2 O 3 heterojunction luminous films and devices are fabricated. • Emission intensity is linked with oxygen vacancies and the optical activity of Er3+. • Oxygen vacancies can be maintained by annealing heterostructures in nitrogen. • Optical activity of Er3+ can be enhanced by reducing the annealing temperature. • The heterostructure devices present the lowest working voltage of 10 V. [ABSTRACT FROM AUTHOR]

The relationship of the threading dislocations (TDs) and InGaN-based quantum well (QW) optical characteristics is studied by temperature-dependent photoluminescence, high-resolution X-ray diffraction and atomic force microscopic. It is found that TDs deteriorate the QW interfacial abruptness, and can enhance the localization effect. Temperature-dependent photoluminescence measurements give evidence that the TDs act as nonradiative recombination (NR) centers in InGaN active layer. According to these results, it is inferred that the influence of TD on the optical properties of InGaN-based QW depends on the competition of localization induced by TDs and the NR effect of TDs. [Copyright &y& Elsevier]

The electric-field-controlled photoluminescence (PL), i.e., electrophotoluminescence (EPL) of ZnO film has been investigated via a ZnO-based metal-insulator-semiconductor (MIS) structure on a silicon substrate applied with different biases. Compared with the PL of ZnO film in the case where there is no bias on the MIS structure, the positive bias with negative voltage applied on silicon substrate significantly enhances the near-band-edge ultraviolet emission while suppressing the deep-level-related visible emissions, whereas the negative bias hardly changes the PL of ZnO film. The mechanism for EPL of ZnO film is proposed in terms of the electric-field effect on the bending of energy bands of ZnO. [ABSTRACT FROM AUTHOR]

Persistent luminescence imaging is accompanied by continuous illumination after the removal of excitation light, which can successfully prevent the generation of autofluorescence. In this study, a mesoporous silica template method is used to prepare uniform and monodisperse porous nanophosphors that can generate X‐ray‐excited persistent luminescence (XEPL). By loading photosensitizers, XEPL effectively excites the photosensitizers to produce reactive oxygen species for killing cancer cells. Imaging of orthotopic hepatic tumors in vivo shows that nanophosphors accumulate in the liver tumors through a passive targeting mechanism, as confirmed by the co‐imaging of bioluminescence and X‐ray‐excited luminescence. Under image‐guidance, X‐ray‐induced photodynamic therapy effectively inhibits the growth of orthotopic hepatic tumors with negligible side effects. Overall, X‐ray‐induced persistent luminescence promotes ultrasensitive imaging and effective inhibition of orthotopic hepatic tumors. [ABSTRACT FROM AUTHOR]

We have investigated the fabrication and luminescent properties of different polymorphs of erbium (Er) silicate in Er-doped silicon oxide films. Silicon oxide films embedded with y-Er2Si2O7 and α-Er2Si2O7 layers have been fabricated with annealing at 1100 °C and 1150 °C, respectively. We demonstrate that y-Er2Si2O7 shows a stronger photoluminescence (PL) intensity, a longer PL lifetime, and a weaker PL thermal quenching effect than α-Er2Si2O7 due to the larger density of optically active Er ions, larger Er–Er average distance, higher symmetry, and stronger Er-O bonding. The Er lifetime–density product of y-Er2Si2O7 is as high as 3.5 × 1018 s cm−3 and is at least 2.4 times as large as that of α-Er2Si2O7 making y-Er2Si2O7 an excellent candidate for high optical gain. [ABSTRACT FROM AUTHOR]

1.54 μm photoluminescence and electroluminescence are achieved from erbium doped Ga 2 O 3 films on silicon substrates and corresponding devices fabricated by sputtering, respectively. Efficient energy transfer between Ga 2 O 3 and erbium ions is realized in optical pumping, with the energy transfer efficiency of 54.9%. The ∼1.54 μm electroluminescence of erbium ions here is proved to originate from indirect excitation, different from the conventional impact excitation by hot electrons. Herein, the light emitting devices present a turn-on voltage of ∼13 V and onset electric field of 1.4 MV/cm. This work demonstrates the potential of preparing practical electrical-driven silicon-based light sources from erbium doped Ga 2 O 3 films. • Er doped Ga 2 O 3 films on p-Si is prepared by sputtering. • ∼1.54 μm photoluminescence is achieved by energy transfer between Ga 2 O 3 and Er. • Er ions are located at the octahedron sites of Ga ions. • ∼1.54 μm electroluminescence is realized by energy transfer in Ga 2 O 3 hosts on Si. • The light-emitting devices present the turn-on voltage of ∼13 V. [ABSTRACT FROM AUTHOR]

Three ZnII and CdII complexes with Y-shaped dicarboxylate ligands, namely [Zn(L1)(2,2′-bpy)2(H2O)] ·2H2O ( 1), [Zn(L1)(bpp)(H2O)] ( 2), and [Cd(L1)(H2O)] ·H2O ( 3) [H2L1 = N-phenyliminodiacetic acid, 2,2′-bpy = 2,2′-bipyridine, bpp = 1,3-bis(4-pyridyl)propane] were synthesized and characterized by elemental analysis, IR spectroscopy single-crystal X-ray diffraction, and thermogravimetric analyses. Compound 1 shows an hydrogen-bonded 2D network, whereas compound 2 is an infinite 1D wavy chain structure, though O-H ···O hydrogen-bonded to form a 2D network. Compound 3 displays a 2D uninodal 3-connected Shubnikov plane net with the point symbol of (4.82). Moreover, the solid-state such as thermal stabilities and fluorescence properties of 1- 3 were also investigated. [ABSTRACT FROM AUTHOR]

Indirect excitation of Er3+ ions via energy transfer from silicon nano-clusters (Si-NCs) is demonstrated in silicon rich oxynitride films with different Si excess concentrations. Excess Si shows competitive effects on Er3+ luminescence. It could enhance the Er3+ emission efficiency while it degrades the energy transfer efficiency and density of optically active Er3+ ions at the same time. Furthermore, coalescence of Si-NCs is observed in the samples with high Si excess concentrations, reducing the density of sensitizers and their coupling with Er. [ABSTRACT FROM AUTHOR]

Two new coordination polymers, namely, [Zn(bdc)(mbix)] n ( 1) and {[Cd2(bdc)2(mbix)2] ·H2O} n ( 2) [H2bdc = 5-hydroxylisophthalic acid, mbix = 1,3-bis(imidazol-1-yl-methyl)benzene], were obtained under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, as well as powder- and single-crystal X-ray diffraction. Compound 1 exhibits a 2D puckered layer with (4,4) topology, which is further interconnected by hydrogen bonding interactions leading to a 3D supramolecular architecture. Compound 2 features a 5-connected 3D network with bnn (46.64) topology based on the dinuclear CdII subunits. In addition, solid-state properties such as thermal stabilities and photoluminescent properties of compounds 1 and 2 were also investigated. [ABSTRACT FROM AUTHOR]

Abstract: A novel and simple chemical reaction method has been developed to synthesize the Tb(OH)3 nanorods with diameters of 20–30 nm and lengths of about 300 nm at 90 °C using cyclohexylamine as the alkaline source. The formation mechanism for the synthesis of the Tb(OH)3 nanostructures with different morphologies has been primarily discussed. [Copyright &y& Elsevier]