Electrical and optical behavior of tungsten oxide based electrochromic devices.

A broad set of phenomenological analysis tools, aimed at isolating generic characteristics of electrochromic (EC) device behavior from measured data with minimal reference to specific models, have been developed. The tools, which involve both directly-measured and derivative parameters, are applied in a demonstrative manner to specific EC devices; step-potential and step-current excitations are considered, along with variations in applied potential, imposed current, film thickness, insertion species, and series resistance. The step-current methods are extended and applied in appreciable detail to EC devices involving both H- and Li-electrolytes. In the H-based devices, a spontaneous (open-circuit) deintercalation process has been observed; this process is absent in the Li-based devices. In both types of devices, the present work exposes an inherent asymmetry between bleaching (deintercalation) and coloring (intercalation), most prominent at the onset of deintercalation. This asymmetry, and the resulting hysteresis, are explained in terms of a two-phase model. From a corresponding equivalent circuit, it is shown that the bleaching behavior may be well-predicted from the coloring behavior with essentially a single adjustable parameter. Behavior, in terms of measured and derived parameters, of devices using an aqueous H-electrolyte are compared with that of devices using a non-aqueous Li-electrolyte. The curves representing the various aspects of behavior for each device are generally similar in shape and may be made approximately to coincide through a linear scaling relation, suggesting that similar fundamental processes govern behavior in both types of devices. Preliminary work towards a model to predict the effect of the size of the insertion species on the intercalation/deintercalation behavior is performed. Additionally, a phenomenological site-saturation model for the optical efficiency is proposed and shown to predict well the observed behavior with no adjustable parameters. The tungsten-oxide films used in the present study, prepared through a novel wet-chemical synthesis and processing procedure involving the use of a transient additive, have been characterized in terms of their resulting microstructures, stoichiometries, and EC behavior. Additionally, the effect of the additive on these properties has been assessed. Finally, identification of particularly fertile avenues for investigation of the means to construct made-to-order devices of the future is also attempted

Modelling of dynamic wetting phenomena

A general dynamic wetting model is presented in which surface and gravitational driving energies are balanced against energy lost through bulk viscous dissipation. Behavior is described in terms only of independently measurable quantities, with no adjustable parameters. Additionally, the model can be expressed so as to predict liquid viscosity as a function of dynamic wetting behavior. Application of the model to a lead-silicate liquid on a gold substrate demonstrate excellent agreement of the model with experiment. The general framework of the model is especially amenable to the incorporation of other physico-chemical processes which may impact dynamic wetting phenomena. Examples are given which extend the model to specific cases where substrate roughness and/or substrate dissolution are important. Additionally, the dynamic wetting model is extended to porous substrates, accounting for the effects of composite interface formation and depletion of the liquid via capillary flow

Content Analytics System for Social Customer Relationship Management

We propose to demonstrate a system that helps enterprises manage their social Customer Relationship Management (CRM) presence. Our system performs deep analytics over consumer posts and authors to help companies monitor their CRM presence, and to identify and respond to actionable posts. In this paper we share challenges and experiences in building this system. Findings yield a step change in the ability to implement social systems for customer care and leverage communities as effective proxies for CRM. This work also identifies novel knowledge and data mining challenges, such as identifying content that requires enterprise action, and prioritizing actionable posts based on various types of intent