Mesophase Transitions, Surface Functionalization, and Growth Mechanism of Semiconducting 6PTTP6 Films from Solution

Abstract

The grain structure is compared for films of the organic semiconductor 6PTTP6 prepared in the open air and in a closed, static atmosphere saturated with xylene vapor. The effect of surface functional groups affixed to the dielectric substrate on the grain appearance and film mobility is probed, to determine optimal fabrication conditions for films with usable mobility, high on/off ratio, and good uniformity. A single-crystal device, also obtained from solution deposition under a particular set of conditions, is characterized and displays an expected higher mobility, >0.1 cm2/Vs. Mesophases are identified in the presence and absence of the xylene and tentatively identified through polarized optical microscopy (POM). Finally, a preliminary observation of the film evolution using an in situ X-ray diffraction (XRD) technique is reported, and lattice spacings are assigned.

Monolayer‐Dimensional 5,5′‐Bis(4‐hexylphenyl)‐2,2′‐bithiophene Transistors and Chemically Responsive Heterostructures

“…The film thickness is expressed in monolayer units. Previous XRD results show that the monolayer spacing of 6PTTP6 is 3 nm, [1,21] consistent with the monolayer thickness measured by AFM, as shown in Figure 2. All the islands are plates of monolayers (not three-dimensional clusters), with thickness around 3 nm.…”

Melt‐Processing of Conjugated Liquid Crystals: A Simple Route to Fabricate OFETs

“…Using Bragg's law, this series of peak gives an interlayer spacing (d) of 30.1±0.1 Å in agreement with the value reported previously. [26,28] By contrast, the melted films (0.5-5 lm) showed two distinct series of intense peaks suggesting the presence of two different crystalline phases. The melted films were at least as highly ordered as the evaporated films.…”

“…Similar behavior has been previously reported for solutiondeposited films of DH-PTTP. [28] The solid-state structure of DH-PTTP was determined by using X-ray crystallography and the arrangement of the molecules was compared to that found for the evaporated and melted films. Slow evaporation of a concentrated DCM solution of DH-PTTP gave monoclinic single crystals with a P21/c space group and two molecules per unit cell.…”

Plastic electronic devices: From materials design to device applications

“…The oligomer 5,5Ј-bis(hexylphenyl)-2,2Ј-bithiophene deposited from solution [77] exhibits similar electrical properties to the polymers, though the patterning methods are not as fully developed. This oligomer also traverses mesophases during the solution deposition process [47].…”