Ni-Doped Garnet Solid-Solution Phosphor-Converted Broadband Shortwave Infrared Light-Emitting Diodes toward Spectroscopy Application.

Broadband shortwave infrared (SWIR) light-emitting diodes (LEDs), capable of advancing the next-generation solid-state smart invisible lighting technology, have sparked tremendous interest and will launch ground-breaking spectroscopy and instrumental applications. Nevertheless, the device performance is still suppressed by the low quantum efficiency and limited emission bandwidth of the critical phosphor layer. Herein, we report a high-performance Ni-doped garnet solid-solution broadband SWIR emitter centered at ∼1450 nm with a large full-width at half-maximum of ∼300 nm, thereby fabricating, for the first time, a directly excited Ni-doped garnet solid-solution phosphor-converted broadband SWIR LED device.

The dependence of the boson peak on the thickness of CuZr film metallic glasses.

In this study, intensive calculations were performed to investigate the behavior of the low-temperature excess heat capacity of Cu50Zr50 ultrathin film metallic glasses. Our results show that there is a well-defined boson peak in the film metallic glasses and that the boson peak height exhibits an obvious size-dependent feature. Furthermore, there is a critical thickness dc in the curves between the boson peak height and the thickness, where the boson peak height changes abruptly.

A comprehensive study of the red persistent luminescence mechanism of YOS:Eu,Ti,Mg.

YOS:Eu,Ti,Mg, a persistent luminescence (PersL) material that exhibits eye-sensitive red emission for longer than 4-5 h, has attracted much attention and has been intensively researched over the past decade. If it is figured out how to prolong its decay time for longer than 8 h, the amazing candle-like red PersL performance, once lit, can illuminate a room all night without electricity. However, the PersL mechanism is still confusing, since different investigators have their own unique understanding about it based on their personal experimental observations.

Reaction mechanism between small-sized Ce clusters and water molecules II: an ab initio investigation on Ce (n = 1-3) + mHO (m = 2-6).

Possible reactions between the products of the three independent reactions involving a small Ce cluster and a single water molecule, Cen + H2O (n = 1-3), and an additional H2O molecule are systematically investigated. The ground-state isomers of the final products and the reaction pathways involving multiple water molecules are predicted. We find that under either ambient or UV-irradiation conditions, all the reactions can entail low energy barriers.

Structural origin of the high glass-forming ability of CeGaCu alloys.

The CeGaCu amorphous alloy has a good glass-forming ability and many special properties. However, its structure at the atomic scale is unclear. We systematically investigated the structure evolution of Ce70GaxCu30-x (x = 6, 10, 13) glass formation melts by ab initio molecular dynamics (AIMD) simulations.

Reaction mechanism between small-sized Ce clusters and water molecules: an ab initio investigation on Ce + HO.

Reactions of small-sized cerium clusters Cen (n = 1-3) with a single water molecule are systematically investigated theoretically. The ground state structures of the Cen/H2O complex and the reaction pathways between Cen + H2O are predicted. Our results show the size-dependent reactivity of small-sized Ce clusters.

Understanding the quenching nature of Mn in wide band gap inorganic compounds: design principles for Mn phosphors with higher efficiency.

Mn4+ doped phosphors, as an alternative to rare-earth element doped phosphors, have attracted immense attention owing to their ultrahigh quantum efficiency of red emission for potential applications in high rendering white LEDs (light-emitting diodes). Their performance can be largely affected by quenching phenomena such as thermal quenching, concentration quenching and the quenching induced by some intrinsic/extrinsic defects. However, the quenching mechanisms due to the defect levels and host band are still incompletely understood.

Rutile TiO(011)-2 × 1 Reconstructed Surfaces with Optical Absorption over the Visible Light Spectrum.

The stable structures of the reconstructed rutile TiO(011) surface are explored based on an evolutionary method. In addition to the well-known "brookite(001)-like" 2 × 1 reconstruction model, three 2 × 1 reconstruction structures are revealed for the first time, all being more stable in the high Ti-rich condition. Importantly, the predicted TiO-2 × 1 surface model not only is in excellent agreement with the reconstructed metastable surface detected by Tao et al.

New structures of bilayer germanium nanosheets predicted by a particle swarm optimization method.

A global search for the stable structures of bilayer Ge (BLG) is performed, and the most stable and meta-stable BLG structures are predicted for the first time. Phonon-spectrum calculations and ab initio molecular dynamics simulations confirm their dynamical and thermal stability. The computed electronic structures suggest that the most stable structure is metal while the meta-stable structure of BLG is a semiconductor with an indirect band gap (0.

The influence of liquid Pb-Bi on the anti-corrosion behavior of Fe3O4: a first-principles study.

In this work, the influence of Pb and Bi atoms on the anti-corrosion behavior of the oxide film (Fe3O4) formed on steel surface is investigated based on first-principles calculations. Through calculations of the formation energies, we find that Pb and Bi atoms can promote the formation of point defects, such as interstitial atoms and vacancies in Fe3O4. Besides, the effects of the concentration of Pb (or Bi) and pressure on the formation of these defects are also studied.

Persistent Luminescence Hole-Type Materials by Design: Transition-Metal-Doped Carbon Allotrope and Carbides.

Electron traps play a crucial role in a wide variety of compounds of persistent luminescence (PL) materials. However, little attention has been placed on the hole-trap-type PL materials. In this study, a novel hole-dominated persistent luminescence (PL) mechanism is predicted.

Highly efficient visible-light-driven photocatalytic activities in synthetic ordered monoclinic BiVO4 quantum tubes-graphene nanocomposites.

Photocatalytic purification of polluted water is a very promising way to alleviate the increasingly serious water resources crisis. Despite tremendous efforts, developing visible-light-driven photocatalysts with high activity at low cost still remains a great challenge. Herein, we report for the first time the design and synthesis of ordered m-BiVO(4) quantum tubes-graphene nanocomposites that exhibit unprecedented visible-light-driven photocatalytic activities, over 20 times faster than that of commercial P25 or bulk BiVO(4) and roughly 1.

Identifying structural distortion in doped VO2 with IR spectroscopy.

Doping VO(2) with tungsten can lower the metal-insulator transition (MIT) temperature and thus provide a controlled means for tailoring the MIT properties of VO(2) materials. Here, infrared spectroscopy has been employed as a tool for identifying structural changes in doped VO(2) as a way of lowering the MIT temperature.

Highly depressed temperature-induced metal-insulator transition in synthetic monodisperse 10-nm V2O3 pseudocubes enclosed by {012} facets.

Monodisperse 10-nm V(2)O(3) pseudocubes enclosed by {012} facets were successfully synthesized for the first time via a novel and facile solvothermal method, offering the first opportunity to elucidate the effect of finite-size and facet on the temperature-induced reversible metal-insulator transition (MIT) behavior of V(2)O(3). Very excitingly, the transition temperature of these V(2)O(3) pseudocubes drastically depressed from 133 K to 36 K and their corresponding hysteresis width highly narrowed from 17 K to 5 K, compared to the MIT behaviors of other irregular V(2)O(3) particles with average sizes of 10 nm, 20 nm, 40 nm, 170 nm and 2 μm. Notably, the size-related surface energy, grain boundary connectivity and volume expansion could be used to account for their strong size-dependent transition temperature and hysteresis width.