Vitreous Thin Films Research Articles

Role of surfactants in electron cryo-microscopy film preparation

Single-particle electron cryo-microscopy (cryo-EM) has become an effective and straightforward approach to determine the structure of membrane proteins. However, obtaining cryo-EM grids of sufficient quality for high-resolution structural analysis remains a major bottleneck. One of the difficulties arises from the presence of detergents, which often leads to a lack of control of the ice thickness. Amphipathic polymers such as amphipols (APols) are detergent substitutes, which have proven to be valuable tools for cryo-EM studies. In this work, we investigate the physico-chemical behavior of APol- and detergent-containing solutions and show a correlation with the properties of vitreous thin films in cryo-EM grids. This study provides new insight on the potential of APols, allowing a better control of ice thickness while limiting protein adsorption at the air-water interface, as shown with the full-length mouse serotonin 5-HT3A receptor whose structure has been solved in APol. These findings may speed up the process of grid optimization to obtain high-resolution structures of membrane proteins.

Structuring of solution processed and thermally evaporated As33S67 thin films by soft stamp hot embossing method

Chalcogenide As33S67 vitreous thin films prepared by thermal evaporation and spin-coating method from n-propylamine and n-hexylamine based solutions were structured using hot embossing technique with soft polydimethylsiloxane (PDMS) stamps. The influence of deposition method and conditions as well as thermal history of the samples was studied. Obtained results gave evidence that solution processed thin films can be structured at significantly lower temperatures in comparison with thermally evaporated thin films, even below Tg of the glass. Theory explaining observed phenomena based on the structural differences of solution processed and thermally evaporated thin films was proposed. Notable decrease in required embossing temperature of solution processed thin films will widen the range of chalcogenide glass compositions that can be structured by soft stamp hot embossing as well as the pool of usable substrates (such as substrates with lower temperature stability).

Dy3+ and Tb3+ co-doped boro-phosphate sol–gel vitreous thin films

A new glass with the molar composition 20B2O3-60P2O5-10ZnO-5Dy2O3-5Tb2O3 was obtained by sol–gel method and deposited on silicate glass substrates by spin-coating, at different rotation speeds and number of layers. XRD proved the vitreous state of the thin films. FTIR spectroscopy revealed the borate, meta-phosphate and mixed boro-phosphate networks in the samples. SEM, combined with AFM, demonstrated the advantages of higher deposition speeds on the higher uniformity and lower roughness of the thin films. The proposed composition of the films was proved by EDS investigations, which identified all elements in the desired proportions. Absorption bands and luminescence emissions specific to Dy3+ and Tb3+ ions are identified. These multi-component films can be used for magneto-optical devices, laser mirrors and luminescent applications.

Er:YAB nanoparticles and vitreous thin films by the polymeric precursor method

The synthesis of Y0.9Er0.1Al3(BO3)4 crystalline powders and vitreous thin films were studied. Precursor solutions were obtained using a modified polymeric precursor method using d-sorbitol as complexant agent. The chemical reactions were described. Y0.9Er0.1Al3(BO3)4 composition presents good thermal stability with regard to crystallization. The Y0.9Er0.1Al3(BO3)4 crystallized phase can be obtained at 1,150 °C, in agreement with other authors. Crack- and porosity-free films were obtained with very small grain size and low RMS roughness. The films thickness revealed to be linearly dependent on precursor solution viscosity, being the value of 25 mPa s useful to prepare high-quality amorphous multi-layers (up to ∼ 800 nm) at 740 °C during 2 h onto silica substrates by spin coating with a gyrset technology.

Vitreous tin oxide-based thin film electrodes for Li-ion micro-batteries

Sputter deposited thin films from a Sn/(SnO)(B 2O 3) 0.3(P 2O 5) 0.2 composite target are investigated as an alternative to the lithium metal anode for lithium-ion micro-batteries. Experimental conditions related to the manufacturing of the target and elaboration of the vitreous thin films are described. Chemical and physical properties of the thin layer films are presented. Regarding the electrochemical behavior, vitreous tin oxide-based thin films were found to be able to store and reversibly exchange lithium ions evidencing the feasibility of the thin film electrode concept.

Optical reflectivity study of photodissolution kinetics in GeSe 3 vitreous thin films

Optical reflectivity measurements on amorphous GeSe 3 obtained by flash evaporation and photodoped with Ag have been carried out. Cooling the sample during Ag evaporation avoids Ag diffusion but when the sample returns to room temperature photodissolution always occurs even in absolute darkness. The ratio between Ag and GeSe 3 thicknesses for a complete photodissolution of Ag film is about 1/3. After complete photodissolution the thickness of the photodoped region follows the relation d PR = d Ag + d GeSe 3 . The rate of the phenomenon increases when GeSe 3 is previously exposed. The kinetics of the process are determined from an optical model. This optical model requires values of the optical constants of each layer: GeSe 3, photodoped region and Ag. A method taking into account the thick glass substrate and thin film effects gives the constants n i and k i of the film from transmission and reflection measurements in the wavelength range 0.4−3 μm. From these values, the reflectivity-time dependence of the multi-layer system Ag-photodoped region-GeSe 3 during photodoping is calculated and can be compared with the time dependence of the electrical resistance of the Ag layer.

Lithium solid state glass-based microgenerators

Abstract Vitreous thin films of lithium solid electrolyte associated with vitreous host materials have been deposited by RF sputtering or thermal evaporation to form microbatteries. The deposition parameters and the electrical properties of the thin films are reported. The best results have been obtained with the following cells: LiƒLi 2 OB 2 O 3 ƒV 2 O 5 P 2 O 5 , OCV: 3.6 V; HMDSƒLiƒLi 2 OB 2 O 3 P 2 O 5 ƒV 2 O 5 TeO 2 , OCV: 3.2 V, where HMDS is the protective layer of hexamethyldisiloxane.

The optical properties of vitreous As xSe 1 − x thin films

The refractive indices of vitreous thin films of As x Se 1 − x containing up to 50% As, produced by evaporation of both AsSe mixtures and the compound As 2Se 3, have been measured. The refractive index, which increases with increasing As content, can be varied at will by up to 15%. Oxide impurities lead to increased absorption. The films are physically robust and transparent in the range 0.8–15 μm.