Thursday, 03 April, 2014
UT Host: Dr. Brian Long
Speaker: Dr. Wei You, University of North Carolina
Title: "Rational Design of Conjugated Polymers towards Bulk Heterojunction Solar Cells of High Efficiencies: Lessons, Accomplishments, and Future"
In the past two decades, the bulk heterojunction (BHJ) organic photovoltaic cells, arguably one of the hottest research fields, has attracted tremendous amount of research efforts. Impressive progress has been made through synergistic efforts of chemists, physicists, and engineers. For example, the efficiency has reached 8 – 10% recently. Nevertheless, the research community is actively looking for answers to the central question: how to rationally design ideal polymers to approach 15% efficiency and beyond?
I will summarize the design criteria for "ideal" polymers to be used with PCBM to further improve the efficiency of BHJ photovoltaic devices. Specifically, I will focus on three main topics: (a) design of new conjugated backbone to control the band gap and energy levels; (b) the significant influence of "trivial" side chains; (c) the impact of substituents such as F. A number of new polymers will be discussed in detail to elaborate these topics. A design motif has been proposed, which successfully produced polymers that demonstrated over 8% efficiency in BHJ devices.
But the grand challenge still remains: can we reach an even higher efficiency of BHJ solar cells with intelligently designed new (and better) materials? To answer this question, I will further discuss a few outstanding issues, and make recommendations.
This seminar is not web cast
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