Enhanced hole carrier transport due to increased intermolecular contacts in small molecule based field effect transistors

TitleEnhanced hole carrier transport due to increased intermolecular contacts in small molecule based field effect transistors
Publication TypeJournal Article
Year of Publication2013
AuthorsDharmapurikar, SS, Arulkashmir, A, Das, C, Muddellu, P, Krishnamoorthy, K
JournalACS Applied Materials & Interfaces
Volume5
Issue15
Pagination7086-7093
Date PublishedAUG
ISSN1944-8244
Keywordshole mobility, i-indigo, organic field effect transistor, quadrupole interaction, small molecules, triphenylamine
Abstract

Small molecules and oligomers can be synthesized with very high purity and precise molecular weights, but they often do not form uniform thin films while processed from solution. Decreased intermolecular contacts between the small molecules are another disadvantage. To increase the intermolecular contacts in small molecules, we have chosen i-indigo, as one of the conjugated molecular units. The electron poor i-indigo has been connected with electron rich triphenylamine to synthesize a donor-acceptor-donor type small molecule. The propeller shaped triphenylamine helps to increase the solubility of the small molecule as well as isotropic charge transport. The intermolecular spacing between the molecules has been found to be low and did not vary as a function of thermal annealing. This implies that the intermolecular contacts between the small molecules are enhanced, and they do not vary as a function of thermal annealing. Organic field effect transistors (OFET) fabricated using a small molecule exhibited a hole carrier mobility (mu) of 0.3 cm(2)/(V s) before thermal annealing. A marginal increase in mu was observed upon thermal annealing at 150 degrees C, which has been attributed to changes in thin film morphology. The morphology of the thin films plays an important role in charge transport in addition to the intermolecular spacing that can be modulated with a judicious choice of the conjugated molecular unit.

DOI10.1021/am401379a
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)5.9
Divison category: 
Polymer Science & Engineering