Reflectance and durability of Ag mirrors coated with thin layers of Al_2O_3 plus reactively deposited silicon oxide

Hass, G.; Heaney, James B.; Herzig, H.; Osantowski, John F.; Triolo, Jack J.

doi:10.1364/ao.14.002639

Cited by 52 publications

(11 citation statements)

References 10 publications

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“…The interactions between silver and sulfur have been recognized since antiquity and are technologically relevant for preservation, chemistry, medicine, and engineering applications. − Acanthite tarnish gradually accumulates on evaporated silver metal at an approximate rate of about half a nanometer per day . Bennet found that the reaction is fastest on rough surfaces devoid of Ag 2 S and observed a tendency for silver sulfide to deposit in clumps, rather than in a continuous passivating film .…”

Section: Progression Of the Tarnishing Reactionmentioning

confidence: 99%

Tarnishing Silver Metal into Mithrene

et al. 2018

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Silver metal exposed to the atmosphere corrodes and becomes tarnished as a result of oxidation and precipitation of the metal as an insoluble salt. Tarnish has so poor a reputation that the word itself connotes corruption and disrespectability; however, tarnishing is a facile synthetic approach for preparing thin metal-sulfide films on silver or copper metal that might be exploited to prepare more elaborate materials with desirable optoelectronic properties. In this work, we prepare luminescent semiconducting thin films of mithrene, a metal–organic chalcogenolate assembly, by replacing the tarnish-causing atmospheric sulfur source with diphenyl diselenide. Mithrene, or silver benzeneselenolate [AgSePh]∞, is a crystalline solid that contains both an organic supramolecular phase and a two-dimensional inorganic coordination polymer phase. This compound gradually accumulates as the sole product of silver metal corrosion. The chemical reaction is carried out on metallic silver thin films and yields crystalline films with thicknesses ranging from 5 to 100 nm. We use the large-area films (>6 cm2) afforded by this method to measure the optical properties of this compound. The mild-temperature, wafer-scale processing of hybrid chalcogenolate thin films may prove useful in the application of hybrid organic–inorganic materials in semiconductor devices and hierarchical architectures.

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Section: Progression Of the Tarnishing Reactionmentioning

confidence: 99%

Tarnishing Silver Metal into Mithrene

et al. 2018

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“…Normally, one would overcoat the silver with a transparent dielectric to protect it against attack by atmospheric or atomic oxygen. An overcoat can change the reflectivity if deposited in thick enough layers [7]. For simplicity, we will use the optical properties of uncoated silver.…”

Section: A Collectormentioning

confidence: 99%

Critical Look at the Solar Photon Thruster Concept

Fieseler

Anderson

Cable

2015

Journal of Spacecraft and Rockets

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A solar photon thruster is a class of solar sail using multiple reflecting surfaces. Herein, the details of solar photon thruster design are investigated to allow comparison against more typical solar sail configurations. Many potential problems with the solar photon thruster concept have been sidestepped in the literature. Therefore, issues relevant to solar photon thruster operation were investigated, such as the following questions: 1) What are the realistic thrust levels and performance that such a vehicle might experience? 2) Do lightweight materials capable of handling the high heat fluxes, where the light is concentrated and reflected, exist? 3) How significant are the reflection losses due to having multiple reflective surfaces? 4) Can a large flexible mirror really focus the light sufficiently well to allow the solar photon thruster concept to work? It is found that any solar photon thruster will have a significantly inferior performance to a similarly sized flat solar sail. The maximum reflectivity of the surfaces typically used by solar sails and solar photon thrusters is determined; it is also found that the thermal issues of concentrating sunlight to a small focus are difficult but manageable and that using a large flexible metallized plastic surface as the main light-collecting surface, although suitable for a normal solar sail, is an extreme challenge for the solar photon thruster concept. NomenclatureA c , A s = area of collector and area of secondary, respectively, m 2 a = absorptivity B= non-Lambertian coefficients e = emissivity L = length, m M = mass, kg P in;d = power incident on the director, W P r = radiation pressure, N∕m 2 p = momentum, kg · m∕s S = spectral irradiance, W∕m 2 · μ s = specularity, unitless T = temperature, K W = solar irradiance, W∕m 2 ε r = reflective efficiency ρ c , ρ d = reflectivity σ = Stefan-Boltzmann constant, W∕m 2 · K 4 σ r = radial stress, N∕m 2

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“…Protective oxide overcoats 2,7,[14][15][16][17][18][19][20][21][22] usually have absorption bands in the thermal infrared that can dramatically increase emissivity, exhibit significant losses at high angles of incidence, show transmission dips near 3µ due to water adsorption, and impose significantly increased complexity and cost on the deposition system. Reflectance, scattering, adhesion, and durability of evaporated Al films are a function of several interdependent deposition parameters listed below in order of importance:…”

Section: Coating Objectivesmentioning

confidence: 99%