Ultrafast charge-transfer in organic photovoltaic interfaces: geometrical and functionalization effects

Understanding the microscopic mechanisms of electronic excitation in organic photovoltaic cells is a challenging problem in the design of efficient devices capable of performing sunlight harvesting. Here we develop and apply an ab initio approach based on time-dependent density functional theory and Ehrenfest dynamics to investigate photoinduced charge transfer in small organic molecules. Our calculations include mixed quantum–classical dynamics with ions moving classically and electrons quantum mechanically, where no experimental external parameter other than the material geometry is required. We show that the behavior of photocarriers in zinc phthalocyanine (ZnPc) and C60 systems, an effective prototype system for organic solar cells, is sensitive to the atomic orientation of the donor and the acceptor units as well as the functionalization of covalent molecules at the interface. In particular, configurations with the ZnPc molecules facing on C60 facilitate charge transfer between substrate and molecules that occurs within 200 fs. In contrast, configurations where ZnPc is tilted above C60 present extremely low carrier injection efficiency even at longer times as an effect of the larger interfacial potential level offset and higher energetic barrier between the donor and acceptor molecules. An enhancement of charge injection into C60 at shorter times is observed as binding groups connect ZnPc and C60 in a dyad system. Our results demonstrate a promising way of designing and controlling photoinduced charge transfer on the atomic level in organic devices that would lead to efficient carrier separation and maximize device performance.

Giving Afghan women a voice:Women's writing in Afghanistan.

This article considers how far women's rights have improved in Afghanistan since the intervention by the international community in 2001. It examines this question through the author's experience of working with an Afghan women's writing group. It looks at the tension between allowing Afghan women to voice their experiences, and the danger of their writing embracing depictions of the female as ‘victim’. It concludes that while depictions of Afghan womanhood may appear to promote ‘negative’ images, the women themselves offer positive role models.

Face description for perceptual user interfaces

[EN]We investigate mechanisms which can endow the computer with the ability of describing a human face by means of computer vision techniques. This is a necessary requirement in order to develop HCI approaches which make the user feel himself/herself perceived. This paper describes our experiences considering gender, race and the presence of moustache and glasses. This is accomplished comparing, on a set of 6000 facial images, two di erent face representation approaches: Principal Components Analysis (PCA) and Gabor lters. The results achieved using a Support Vector Machine (SVM) based classi er are promising and particularly better for the second representation approach.

Multiple face detection at different resolutions for perceptual user interfaces

[EN]This paper describes in detail a real-time multiple face detection system for video streams. The system adds to the good performance provided by a window shift approach, the combination of different cues available in video streams due to temporal coherence. The results achieved by this combined solution outperform the basic face detector obtaining a 98% success rate for around 27000 images, providing additionally eye detection and a relation between the successive detections in time by means of detection threads.

Hand pose detection for vision-based gesture interfaces

[EN]Vision-based applications designed for humanmachine interaction require fast and accurate hand detection. However, previous works on this field assume different constraints, like a limitation in the number of detected gestures, because hands are highly complex objects to locate. This paper presents an approach which changes the detection target without limiting the number of detected gestures. Using a cascade classifier we detect hands based on their wrists. With this approach, we introduce two main contributions: (1) a reliable segmentation, independently of the gesture being made and (2) a training phase faster than previous cascade classifier based methods. The paper includes experimental evaluations with different video streams that illustrate the efficiency and suitability for perceptual interfaces.

Beyond Policy - Empowerment as choice or empowerment as voice?

An Enterprise Opportunity for Entrepreneurial Students: Student Enterprise Development and Experience Assessed through the Student Voice

Purpose: This research investigates the effectiveness of an experiential learning approach, available to students in all disciplines that combined a hands-on entrepreneurial and enterprise experience with professional consultant mentoring by using a competition to win business start-up funding. Design/methodology/approach: Students at a UK university had the chance to enter a competition in which they developed an entrepreneurial idea and then designed and presented a business plan to win business start-up capital. Students who were entrepreneurially motivated, but who lacked capital to start up their business, were targeted, as these students have been argued to benefit the most from a combination of business plan training and entrepreneurial development. Feedback and data was obtained from the students at each stage of the process and was thematically analysed to assess the development of students’ entrepreneurial skills and knowledge through the experience. Findings: The research found that the benefits gained from this approach included both enterprising and entrepreneurial skills, with the greatest impact being on student confidence and belief in their ability to start a business. The practical skills had a ‘demystifying’ effect on students that made them feel like entrepreneurship and enterprise start-up were attainable. Research limitations/implications: The research focused on students at one UK University and centered on entrepreneurship in a retail business. The competition thus appealed mainly to students who were interested in retail start-up, thus leaving out some enterprising students whose feedback may have been different. In addition, while entrepreneurial skills are assessed in the data, the students who would be interested in the competition would be assumed to be proactive, and this skill was not able to be analyzed. This research is a single case, and thus could be enhanced by more cases and looking at other enterprise start-up means beyond retail. Originality/value: This research makes a case that, in light of literature critical of the use of business plan training in entrepreneurship education, certain students are appropriate candidates for this approach. Specific skills and knowledge can be developed in university students using a live enterprise experience, supported by entrepreneurial mentoring. By making the event extracurricular, the study sought to capture the feedback of students who self-selected into the program, who can benefit most from combined entrepreneurial and business-plan development experience.

Stochastic Modeling of Reversible Biochemical Reaction-Diffusion Systems and High-Resolution Shock-Capturing Methods for Fluid Interfaces

Thesis (Ph.D.)--University of Washington, 2016-08

Concerns and Expectations of Students Participating in Study Abroad Programs: Blogging to Reveal the Dynamic Student Voice

Study abroad programmes (SAP) have become increasingly popular with university students and within academia. They are often seen as an experiential opportunity to expand student learning and development, including increases in global, international, and intercultural competences. However, despite the increasing popularity of and participation in study abroad programmes, many student concerns and uncertainties remain. This research investigates initial pre-departure concerns and apprehensions of students undertaking a one-semester study abroad programme and uses these as context for an examination of violated expectations of students during their programme. The research uses interpretative phenomenological analysis to interpret data collected from regularly-updated blogs composed by students throughout their SAP experience. The process of using blogs to collect data is less formalised than many other approaches of interpretative phenomenological analysis, enabling ‘in the moment’ feedback during the SAP and lending greater depth to the understanding of student perceptions.

The Voice of History and the Message of the National Curriculum: Recontextualising History to a Pedagogic Discourse for Upper Secondary VET

In the reform by the liberal-conservative government of Swedish upper secondary education in 2011, history was recognized as an important part of citizenship education and was introduced into the curriculum for vocational education and training (VET) tracks. Through the concepts of classification and framing, this article explores the process of constructing the history syllabus for VET. The data consist of archived material from the working group responsible for the history curriculum under the Swedish National Agency for Education. The analysis shows that there are competing discourses concerning the relative emphasis on competencies and skills and concerning the emphasis on contemporary and modern history. Although historians, history teachers and other agents are invited to respond to the content of the curriculum, the respondents have no influence on the knowledge structure of the curriculum, which is controlled by agents of the dominant educational ideology. From a critical perspective, this article suggests that the curriculum reflects the instrumental and neoconservative message of the reform through strong classification and framing and through the emphasis on general abilities and a contemporary history that has a more direct explanatory value to contemporary society.

The VOP Voice, December 2014

Spotlight: Meet Tonya Amos Education opportunities Congratulations on one year anniv. Glad tiding from Staff

The VOP Voice, February 1, 2016, Vol. 2

Spotlight on Lynzey Kenworthy, Volunteer Anniversaries, Continuing Education, Trivia, Possible Tax Deduction for Mileage

The VOP Voice, March 1, 2016., Vol. 3

Spotlight on Kelsey Zantigh, Volunteer Anniversaries, Continuing Education, Trivia, OSLTO Annual Report

The VOP Voice, April 1, Vol. 4

Spotlight on Kelli Todd, Volunteer Anniversaries, Continuing Education, Trivia