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Ambipolar Organic Field‐Effect Transistors from Cross‐Conjugated Aromatic Quaterthiophenes; Comparisons with Quinoidal Parent Materials
Author(s) -
Ortiz Rocío Ponce,
Facchetti Antonio,
Marks Tobin J.,
Casado Juan,
Zgierski Marek Z.,
Kozaki Masatoshi,
Hernández Víctor,
Navarrete Juan T. López
Publication year - 2009
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200801066
Subject(s) - ambipolar diffusion , conjugated system , materials science , organic semiconductor , acceptor , raman spectroscopy , field effect transistor , organic electronics , electron acceptor , terthiophene , electron mobility , photochemistry , electron , transistor , chemical physics , polymer , optoelectronics , chemistry , condensed matter physics , physics , optics , composite material , quantum mechanics , voltage
This contribution presents an electrochemical, Raman spectroscopic, and theoretical study probing the differences in molecular and electronic structure of two quinoidal oligothiophenes (3′,4′‐dibutyl‐5,5″‐bis(dicyanomethylene)‐5,5″‐dihydro‐2,2′:5′,2″‐terthiophene and 5,5′‐bis(dicyanomethylene)‐3‐hexyl‐2,5‐dihydro‐4,4′‐dihexyl‐2,2′,5,5′‐tetrahydro‐tetrathiophene) with terminal tetracyanomethylene functionalization and aromatic oligothiophenes where acceptor moieties are positioned at lateral positions along the conjugated chain (6,6′‐dibutylsulfanyl‐[2,2′‐bi‐[4‐dicyanovinylene‐4H‐cyclopenta[2,1‐b:3,4‐b′]dithiophene]). In this way, the consequences of linear and cross conjugation are compared and contrasted. From this analysis, it is apparent that organic field‐effect transistors fabricated with cross‐conjugated tetrathiophene semiconductors should combine the benefits of an electron‐donor aromatic chain with strongly electron‐accepting tetracyanomethylene substituents. The corresponding organic field‐effect transistors exhibit ambipolar transport with rather similar hole and electron mobilities. Moreover, n‐channel conduction is enhanced to yield one of the highest electron mobilities found to date for this type of material.