Organic semiconductor devices

Organic semiconductors are the key materials enabling a variety of (opto)electronic applications, such as organic light-emitting diodes (OLED) for low-power high-brightness displays (such as new Sony XEL television) and solid state lighting; organic field-effect transistors (OFET) for display matrix, RFID, logic circuits and sensors; organic photovoltaics for solar cell applications. The advantage of using organic vs inorganic semiconductors is defined by low-cost device fabrication (often, by solution printing), inherent device flexibility, multifunctionality (eg, combining light-emissive and conductive properties) and the possibility for endless tailoring the properties of the material (and thus the function of the device) through modification of molecular structure.

Organic field-effect transistors are particularly attractive, not only due to paramount significance of (silicon) FET is today's electronics, but also as the key test-beds for fundamental study of semiconducting materials. We fabricate such OFET based on spin-coated or vacuum-sublimed thin films or single crystals of organic molecules, and measuring their electrical characteristics, extract the intrinsic values of charge mobility:

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Two unsolved challenges in the field are achieving high charge mobility (for both holes and electrons), similar to that of inorganic semiconductors (>1-10 cm2/Vs) and improving stability of organic devices. In our group, we integrate molecular design/synthesis together with fundamental physical studies and device fabrication/measurements in order to address both of these challenges. Below are some recent examples of new organic semiconductors studied in our group with corresponding values of charge mobility.

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Apart of using the measured charge mobility to built structure-properties relationships, we actively exploring the potential of organic semiconductors for design of other types of optoelectronic devices, including light-emitting transistors (LET) and photovoltaic diodes.

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Recent papers:

Towards " green " electronic materials. α -Oligofurans as Semiconductors,
O. Gidron, A. Dadvand, Y.Sheynin, M. Bendikov,* D.F. Perepichka,* Chem. Commun. 2011, 1976-1979.

New Highly Emissive Thienylene-Vinylene Oligomers and Co-Polymers for Organic Electronics,
S. Jeeva, O. Lukoyanova, A. Karapanayiotis, A. Dadvand, F. Rosei, D.F. Perepichka*, Adv. Funct. Mater. 2010, 20, 20, 1661-1669.

Quasi Temperature Independent Charge Carrier Mobility in Hexagonal Columnar Mesophases of H-Bounded Benzotristhiophene Derivative,
A. Demenev, S.H. Eichhorn*, T. Taerum, D.F. Perepichka*, S. Patwardhan, F.C. Grozema*, L.D.A. Siebbeles, Chem. Mater. 2010, 22, 1420-1428.

Heterocirculenes as a new class of organic semiconductors,
A. Dadvand, F. Cicoira, K. Yu. Chernichenko, E. S. Balenkova, R. M. Osuna, F. Rosei, V. G. Nenajdenko, D. F. Perepichka, Chem. Commun. 2008, 5354-5356.

A New Structural Motif in Thienoacene Semiconductors: Synthesis, Structure and Properties of Tetrathienoanthracene Isomers,
J. L. Brusso, O. Hirst, A. Dadvand, S. Ganesan, F. Cicoira, C. M. Robertson, R. T. Oakley, F. Rosei, D. F. Perepichka, Chem. Mater. 2008, 20, 2484-2494.

Environmentally stable organic light emitting field effect transistors based on 2-(4-pentylstyryl)tetracene,
F. Cicoira, C. Santato, A. Dadvand, C. Harnagea, A. Pignolet, P. Bellutti, Z. Xiang, F. Rosei, H. Meng, D.F. Perepichka, J. Mater. Chem. 2008, 18, 158-161.

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