WFU Department of Physics Wake Forest University

 

Wake Forest Physics
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WFU Physics Colloquium

TITLE: CHARGE TRANSPORT IN ORGANIC AND HYBRID PEROVSKITE FIELD EFFECT TRANSISTORS

SPEAKER: Yaochuan Mei

Ph.D. Defense

TIME: Friday April 22, 2016 at 3:00 PM

PLACE: Room 101 Olin Physical Laboratory


All interested persons are cordially invited to attend.

ABSTRACT

Organic semiconductors and hybrid organic/inorganic perovskite semiconductors can address new applications, which are off-limits for conventional silicon-based electronics. We fabricate organic field-effect transistors (OFETs) and through the use of several device architectures, in combination with surface treatments, we were able to achieve mobilities as high as 6.8 cm2/Vs. We find that the microstrain induced in the organic semiconductor layer by the mismatch in the thermal expansion between the consecutive device layers generates trapping states and localize charge carriers, leading to a surprising universal scaling between the activation energy of the devices and the interfacial thermal expansion mismatch coefficient. The second class of materials of interest to this study is that of hybrid perovskite methylammonium lead halides. When we developed the first working field-effect transistor on these materials, we were able to measure the nature and dynamics of charge carriers directly. We found balanced ambipolar transport with mobilities of 1 cm2/Vs for both electrons and holes.



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100 Olin Physical Laboratory
Wake Forest University
Winston-Salem, NC 27109-7507
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