Kathleen Meehan

Study of optical and structural characteristics of ceria nanoparticles doped with negative and positive association lanthanide elements

This paper studies the effect of adding lanthanides with negative association energy, such as holmium and erbium, to ceria nanoparticles doped with positive association energy lanthanides, such as neodymium and samarium. That is what we called mixed doped ceria nanoparticles (MDC NPs). In MDC NPs of grain size range around 6 nm, it is proved qualitatively that the conversion rate from Ce4+ to Ce3+ is reduced, compared to ceria doped only with positive association energy lanthanides. There are many pieces of evidence which confirm the obtained conclusion. These indications are an increase in the allowed direct band gap which is calculated from the absorbance dispersion measurements, a decrease in the emitted fluorescence intensity, and an increase in the size of nanoparticles, which is measured using both techniques: transmission electron microscope (TEM) and X-ray diffractometer (XRD). That gives a novel conclusion that there are some trivalent dopants, such as holmium and erbium, which can suppress Ce3+ ionization states in ceria and consequently act as scavengers for active O-vacancies in MDC. This promising concept can develop applications which depend on the defects in ceria such as biomedicine, electronic devices, and gas sensors.

Enhanced Erbium-Doped Ceria Nanostructure Coating to Improve Solar Cell Performance

This paper discusses the effect of adding reduced erbium-doped ceria nanoparticles (REDC NPs) as a coating on silicon solar cells. Reduced ceria nanoparticles doped with erbium have the advantages of both improving conductivity and optical conversion of solar cells. Oxygen vacancies in ceria nanoparticles reduce Ce4+ to Ce3+ which follow the rule of improving conductivity of solar cells through the hopping mechanism. The existence of Ce3+ helps in the down-conversion from 430 nm excitation to 530 nm emission. The erbium dopant forms energy levels inside the low-phonon ceria host to up-convert the 780 nm excitations into green and red emissions. When coating reduced erbium-doped ceria nanoparticles on the back side of a solar cell, a promising improvement in the solar cell efficiency has been observed from 15% to 16.5% due to the mutual impact of improved electric conductivity and multi-optical conversions. Finally, the impact of the added coater on the electric field distribution inside the solar cell has been studied.

Nano-Enriched and Autonomous Sensing Framework for Dissolved Oxygen

This paper investigates a nano-enhanced wireless sensing framework for dissolved oxygen (DO). The system integrates a nanosensor that employs cerium oxide (ceria) nanoparticles to monitor the concentration of DO in aqueous media via optical fluorescence quenching. We propose a comprehensive sensing framework with the nanosensor equipped with a digital interface where the sensor output is digitized and dispatched wirelessly to a trustworthy data collection and analysis framework for consolidation and information extraction. The proposed system collects and processes the sensor readings to provide clear indications about the current or the anticipated dissolved oxygen levels in the aqueous media.

Merging pedagogical approaches: University of Glasgow-UESTC joint education programme in electronics and electrical engineering

The University of Glasgow-University of Electronic Science and Technology of China joint education programme enrolled its first cohort of students in Fall 2013. Continual assessment of the programme was initiated shortly thereafter to monitor student achievement in the programme, to evaluate how well the aims of the programme are being met, and to determine areas where improvements can be made. Several issueswere identified during the review as well as in informal conversations with course instructors, administrative support staff, and students. To quantify the impact of these issues, a study to examine the cultural attitudes, English language communication aptitude, problem-solving skills, learning style, and teacher-student relationship of the first cohort during their first year in its undergraduate programme in electronics and electrical engineering has been proposed The study will adopt an interpretive approach, using a longitudinal multivariate study design, to generate quantified descriptions of how each issue influences student behavior and success in the programme. A follow-on study on the course instructors cultural attitudes, pedagogical approaches, and willingness to adapt is planned. The initial findings from the programme assessment and the proposed studies will be presented at the 2014 Frontiers in Education Conference in Madrid, Spain in October 2014.