Search PubMed⌕ Search

Biomedical subjects

Christian Kloc

Publications and source records attributed to Christian Kloc.

7 recordsLinked to original sources
PubMed2006

Oxygen-related band gap state in single crystal rubrene.

A molecular exciton signature is established and investigated under different ambient conditions in rubrene single crystals. An oxygen-related band gap state is found to form in the ambient atmosphere. This state acts as an acceptor center and assists in the fast dissociation of excitons, resulting in a higher dark and photoconductivity of oxidized rubrene. The band gap state produces a well-defined photoluminescence band at an energy 0.25 eV below the energy of the 0-0 molecular exciton transition. Two-photon excitation spectroscopy shows that the states are concentrated near the surface of naturally oxidized rubrene.

Journal Article↗
PubMed2005

Patterned growth of large oriented organic semiconductor single crystals on self-assembled monolayer templates.

This work demonstrates a method for inducing site-specific nucleation and subsequent growth of large oriented organic semiconductor single crystals using micropatterned self-assembled monolayers (SAMs). We demonstrate growth of oriented, patterned, and large organic semiconductor single crystals for potential use in organic electronic devices. The control over multiple parameters in a single system has not yet been reported. The ability to control various aspects of crystal growth in one system provides a powerful technique for the bottom-up fabrication of organic single-crystal semiconductor devices.

Journal Article↗
PubMed2005

Azinyl sulfides. LXXXI.(1)14-Phenyl-7-thiapyrano[2,3-c;6,5-c']diquinoline-14-carbonitrile.

The molecules of the title compound, C26H15N3S, have a pentacyclic ring system which is almost planar, with the central ring in a flattened boat conformation. The folding angle between the two quinoline rings is 6.75 (7) degrees. The 14-phenyl substituent is in a quasi-axial conformation, while the 14-cyano substituent is in a quasi-equatorial conformation with respect to the thiopyran ring. The S...C-C(phenyl) and S...C-C(CN) angles are 116.8 (2) and 129.3 (2) degrees, respectively. The plane of the phenyl group is nearly coplanar with the plane bisecting the dihedral angle of the pentacyclic ring system.

Journal Article↗
PubMed2005

Pentacene disproportionation during sublimation for field-effect transistors.

At moderate temperatures in flowing gas, pentacene undergoes a disproportionation reaction to produce 6,13-dihydropentacene (DHP) and a series of polycondensed aromatic hydrocarbons, including the previously unknown peripentacene (PP). The process requires activation by heating to 320 degrees C and is possibly catalyzed by impurities such as DHP, 6,13-pentacenequinone (PQ), Al, or Fe found in the starting materials. These impurities also result in a decrease in the intrinsic field-effect mobility (FEM) of pentacene crystals. Subsequent purifications remove such impurities, thus inhibiting the formation of the disproportionation products and increasing the FEM of pentacene (2.2 cm(2)/Vs). These results clarify the importance of purification of semiconductive materials for measurements of intrinsic mobility and optimal device performance.

Journal Article↗
PubMed2004

Synthesis, crystal structure, and transistor performance of tetracene derivatives.

The substitution of chloro or bromo groups in tetracene gives rise to the change of crystal structure, having a substantial effect on carrier transport. Halogenated tetracene derivatives were synthesized and grown into single crystals. Monosubstituted 5-bromo- and 5-chlorotetracenes have the herringbone-type structure, while 5,11-dichlorotetracene has the slipped pi stacking structure. Mobility of 5,11-dichlorotetracene was measured to be as high as 1.6 cm2/V.s in single-crystal transistors. The pi stacking structure, which enhances pi orbital overlap and facilitates carrier transport, may thus be responsible for this high mobility.

Journal Article↗
PubMed2002

Retraction.

Explore the source record for details and available documents.

Retraction Notice↗