Dear Group,
Next Monday Dr. Javad Hashemi, a postdoc candidate will visit us from the
University of Helsinki. He intends to talk about his work on perovskite
solar cells, and is interested in the Clean Energy Project or OLED research
within our group. I'd like people from all subgroups to pick a 30 minute
block to meet with him on *March 28, 2016*. I've attached his talk
abstract below.
Thanks,
Steven
At the end of the last decade, a new class of low-cost/high-efficiency
photovoltaics, based on perovskite materials, emerged from the field of
dye-sensitized solar cells. Since the first report on CH3NH3PbI3 absorbers
with 3.5% efficiency in 2009, their efficiency has been constantly
improving; and as of writing, the record efficiency is 20.1%. Experimental
studies show that the efficiency of perovskite compounds is
sensitive to various factors such as substrate material, synthesis methods,
cell, architecture, etc. However, the physics behind such a sensitivity is
yet to be fully understood while such an understanding is crucial for
optimizing these emerging cells for real-life usage.
In this talk, I will present our extensive problem-oriented study on the
effect of structural deformation on electronic and absorption properties of
CH3NH3PbI3 perovskite. I will show that on the one hand, perovskite can
undergo a considerable structural deformation in its interface with
substrates which affects the stability of the cell, and on the other hand
induced strain can cause a direct-to-indirect band gap transition; and thus
it affects the absorption coefficient of the compound noticeably.
Our results will help to explain some of the experimental findings on the
stability and efficiency of the perovskite cells.
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