Eliana M. F. Vieira; Joao F. Ribeiro; Rui Sousa; Anabela G. Rolo; Manuela M. Silva; Luis M. Goncalves
Abstract
Design and fabrication of reliable materials with high capacity, cycling stability and good adhesion properties for flexible microbatteries remains a challenge. A 2 µm thick flexible solid-state Ge-LiCoO2 battery was fabricated and the structure, composition, thermal, optical, electrical, ...
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Design and fabrication of reliable materials with high capacity, cycling stability and good adhesion properties for flexible microbatteries remains a challenge. A 2 µm thick flexible solid-state Ge-LiCoO2 battery was fabricated and the structure, composition, thermal, optical, electrical, and electrochemical properties of the materials that determine and influence its electrochemical potential were investigated. RF-sputtered lithium cobalt oxide (LiCoO2) cathode and lithium phosphorus oxynitride (LiPON) electrolyte films were fabricated at 120 W and 100 W of power, respectively. A ~ 300 nm thick Ge anode was deposited by e-beam. The full-battery was fabricated using conventional and low-cost PVD processes. X-ray diffraction (XRD) and Raman spectroscopy confirms the hexagonal R͞3m phase of annealed LiCoO2. Differential scanning calorimetry (DSC) technique was applied to investigate the thermal behaviour of the LiPON film with a moderate electrical resistivity of 10 8 Ωcm and high optical transmission (> 75%) in the UV-Visible range. Bending experiments were also performed to evaluate thin-films adhesion and stability. Scanning electron microscopy (SEM) technique was used to evaluate the morphology of films surface and the layered structure of the full-battery. This detailed experimental study allows us to understand the discharge behavior of the fabricated Li-ion battery.
Hong-zhen Li; Zhao-xiang Wang; Dong-hua Jing; Xiang-he Kong; Ke-zhu Yan
Abstract
The formation of two-dimensional crystalline film of n-pentadecane (C15H32) on a flat substrate with attractive forces similar to that of the metals or graphite substrate is investigated with molecular dynamics simulation. By controlling the deposition rate of the molecules, we observed the behavior ...
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The formation of two-dimensional crystalline film of n-pentadecane (C15H32) on a flat substrate with attractive forces similar to that of the metals or graphite substrate is investigated with molecular dynamics simulation. By controlling the deposition rate of the molecules, we observed the behavior in adsorption and conformational change of single molecule and the growing process of the n-pentadecane film. Two distinct sub-processes are recognized in the formation of the crystalline film, the formation of the molecular clusters and the coalescence of the molecular clusters. It is found that the conformational changes are gentle when only or few molecules are deposited on the substrate. However, this change becomes drastic as more molecules are gathered together. The accelerated conformational variation is attributed to the no-bonding molecular interaction.
Zhongsen Yang; Guangjun Zhou
Abstract
Hydrophobic CdSe/ZnS quantum dots (QDs) were embedded in a transparent functional silica film with thickness of 10-15 µm using a sol-gel method. Namely, the QDs were prepared through an organic synthesis using hexadecylamine as a capping agent. When partially hydrolyzed 3-aminopropyltrimethoxysilane ...
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Hydrophobic CdSe/ZnS quantum dots (QDs) were embedded in a transparent functional silica film with thickness of 10-15 µm using a sol-gel method. Namely, the QDs were prepared through an organic synthesis using hexadecylamine as a capping agent. When partially hydrolyzed 3-aminopropyltrimethoxysilane (APS) sol was mixed with a toluene solution of the QDs, the ligand exchange occurred. With subsequent addition of pure H2O, the QDs were transferred into APS sol accompanied with a phase separation. The APS sol with the QDs was condensed to adjust its’ viscosity by the evaporation of solvents at room temperature. After that, functional SiO2 films with tunable QD concentrations and high photoluminescence (PL) efficiency were fabricated by a spin-coating strategy using the condensed APS sol with the QDs. The absorbance at first absorption peak of the QDs revealed a liner increase against the QD concentrations in these films. The PL peak wavelength and full width at half maximum of PL spectra of the QDs in these films remained unchange compared with their initial values in toluene. The QDs were mono-dispersed in these films according to transmission electron microscopy observation. Due to unique properties, these films are utilizable for further applications in optical and electronic devices.
