Simple evaluation of dynamic disorder effects on exciton transport

In this work, we investigate two recently synthesized naphthodithiophene diimide (NDTI) derivatives featuring promising n-type charge transport properties. We analyze the charge transport pathways and model charge mobility with the non-adiabatic hopping mechanism using the Marcus-Levich-Jortner rate constant formulation, highlighting the role of fluoroalkylated substitution in α (α-NDTI) and at the imide nitrogen (N-NDTI) position. In contrast with the experimental results, similar charge mobilities are computed for the two derivatives. However, while α-NDTI displays remarkably anisotropic mobilities with an almost one-dimensional directionality, N-NDTI sustains a more isotropic charge percolation pattern. We propose that the strong anisotropic charge transport character of α-NDTI is responsible for the modest measured charge mobility. In addition, when the role of thermally induced transfer integral fluctuations is investigated, the computed electron–phonon couplings for intermolecular sliding modes indicate that dynamic disorder effects are also more detrimental for the charge transport of α-NDTI than N-NDTI. The lower observed mobility of α-NDTI is therefore rationalized in terms of a prominent anisotropic character of the charge percolation pathways, with the additional contribution of dynamic disorder effects.

Download Full-text

Eliminating Invisible Barriers: Health Web Site Accessibility

Californian Journal of Health Promotion ◽

10.32398/cjhp.v1i1.220 ◽

2003 ◽

Vol 1 (1) ◽

pp. 70-86

Author(s):

Christine Rzepka

Keyword(s):

Health Information ◽

Web Sites ◽

Web Site ◽

People With Disabilities ◽

High Tech ◽

Accessibility Issues ◽

Accessibility Guidelines ◽

Use Of The Internet ◽

Simple Evaluation ◽

The Web

One of the top reasons given for use of the internet is the ability to search for health information. However, much of the planning for web-based health information often fails to consider accessibility issues. If health care organizations and community agencies’ web sites have the latest, most wellresearched information on the health topics of the day, it is useless to those who cannot access it because of invisible technological barriers. Many flashy, high-tech sites were designed only to appeal to the needs of the mainstream population, with no consideration given to how people with disabilities must adapt their use of the web in order to access information. This article addresses issues of access specific to web site development, and will explore barriers to accessibility frequently experienced by web users with disabilities, requirements for ADA compliance, and how people with disabilities use the web. Web site accessibility guidelines, as well as simple evaluation tools, will be discussed. A thorough review of the article will enable even the least tech-savvy of health educators to enhance their skills in planning and evaluating web sites to promote access for people with disabilities.

Download Full-text