Impact of Blend Morphology on Interface State Recombination in Bulk Heterojunction Organic Solar Cells

International audienceThis work is a re-investigation of the impact of blend morphology and thermal annealing on the electrical performance of regioregular P3HT:PC 60 BM. The blend is first characterized by combining atomic force microscopy, X-rays diffraction and Time-of-Flight experiments. Then, current-voltage characteristics of photodiode devices are measured in the dark and under illumination. Finally, the existence of exponential tails of electronic gap states is experimentally confirmed by measuring the device spectral response in the sub-band gap regime. This method reveals the existence of a large density of gap states, which is partially reduced by successive annealing steps. The comparison between drift and diffusion 2 simulations and charge transport experiments show that, when band gap tails are properly taken into account, simulations can satisfactorily reproduce experimental currents under both dark and illumination conditions as a function of voltage and annealing time. This work further confirms the critical impact of tails states on the performance of solar cells

T2-B: CLEAN WATER Outreach Program”

The CLEAN WATER program at Florida Gulf Coast University is an outreach experience that integrates engineering entrepreneurship and regional water quality issues into elementary and middle school classrooms. Coordinated by the U. A. Whitaker College of Engineering and supported by a grant from the EPA, the program combines hands-on classroom activities, physical and virtual field trips and a culminating engineering entrepreneurship challenge on the university campus. Classroom activities include physical models, laboratory testing and analysis, interactive lesson plans, computer simulations, and team based project learning assignments. This paper will discuss the various components of the program as well as provide results of student assessment. Participant feedback will be included along with a discussion on the future direction of the program