Ultraviolet Triggered Switchable Mirrors

Rosenbaum, T. F.; Hoekstra, A.F.Th.

doi:10.1002/1521-4095(20020205)14:3<247::aid-adma247>3.0.co;2-#

Cited by 12 publications

(8 citation statements)

References 18 publications

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“…It exploits the large changes in optical transmission of metal alloys when they absorb hydrogen 19,20 to measure optically the equilibrium pressure of hydride formation ͓see Fig. 1͑b͔͒.…”

Section: Introductionmentioning

confidence: 99%

Highly destabilized Mg-Ti-Ni-H system investigated by density functional theory and hydrogenography

et al. 2008

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Using hydrogenography, we recently mapped the thermodynamic properties of a large range of compositions in the quaternary Mg-Ti-Ni-H system. The enthalpy of hydride formation of Mg-Ni alloys is significantly altered upon Ti doping. For a small range of compositions, we find a hydrogenation enthalpy ⌬H = −40 kJ ͑mol H 2 ͒ −1 , which is the desired enthalpy for hydrogen storage at moderate temperature and pressure. This enthalpy value is surprising since it is significantly less negative than the ⌬H of the Mg-Ni and Mg-Ti hydrides. The nanostructure of the Mg-Ti-Ni-H films hinders a direct determination of the hydride phases involved by x-ray diffraction. Using density functional theory calculations for various hydrogenation reaction paths, we establish that the destabilization of the Mg-Ni-H system by Ti doping is due to the formation of Mg 2 Ni and Ti-Ni intermetallics in the as-deposited state, which transform into a metastable Ti-doped Mg 2 NiH 4 phase upon hydrogenation. The Ti-doped Mg 2 NiH 4 phase can be considered as a heavily doped semiconductor.

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Section: Introductionmentioning

confidence: 99%

Highly destabilized Mg-Ti-Ni-H system investigated by density functional theory and hydrogenography

et al. 2008

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“…They can be transformed rapidly from metal to insulator, from reflective mirror to transparent window, simply by changing the surrounding hydrogen gas pressure [11]. Tuning the quantum phase transition by light at sub-Kelvin temperatures in YH 3−δ established that the metal-insulator transition is in the highly correlated limit, with electron-electron interactions playing an important role even deep in the insulator.…”

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confidence: 99%

The electron glass in a switchable mirror: relaxation, ageing and universality

Lee

Oikonomou

Segalova

et al. 2005

J. Phys.: Condens. Matter

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The rare earth hydride YH 3−δ can be tuned through the metal-insulator transition both by changing δ and by illumination with ultraviolet light. The transition is dominated by strong electron-electron interactions, with transport in the insulator sensitive to both a Coulomb gap and persistent quantum fluctuations. Via a systematic variation of UV illumination time, photon flux, separation between electrons, and temperature, we demonstrate that polycrystalline YH 3−δ serves as a model system for studying the properties of the interacting electron glass. Prominent among its features are logarithmic relaxation, aging, and universal scaling of the conductivity.

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“…In addition to ␤-MgH 2 , hydrides based on a metal fcc structure but with 7:1 ordering of Ga 7 Ge-type were synthesized using high pressure for Mg with different transition metals (TM), e.g., Ti, V, Nb [52][53][54]. These hydrides have stoichiometry close to Mg 6-7 (TM)H [13][14][15][16] , and hydrogen atoms occupy interstitial positions (tetrahedral sites for Mg 7 (TM)H 16 were identified by high-energy synchrotron structure analysis [52]). According to [54], the hydrogen atoms help to "glue together" metals that usually are immiscible in the fcc arrangement.…”

Section: Discussionmentioning

confidence: 99%

“…This method relies on dramatic changes in optical transparency of a film in response to hydrogen absorption; most complex metal-hydrogen systems undergo a metal-insulator transition upon hydrogen exposure, which result in a significant increase in optical transparency [14,15]. With a straightforward optical setup, hydrogenography makes it possible to simultaneously monitor hydrogen ab-and desorption for thousands of samples at the same time and thus under exactly the same experimental conditions.…”

Section: Introductionmentioning

confidence: 99%