Selection of the two enantiotropic polymorphs of diF-TES-ADT in solution sheared thin film transistors

Abstract

We report the effect of solution shearing speed on the performances of diF-TES-ADT-based OFETs. X-ray diffraction reveals that the low-temperature phase is predominant at low shearing speed, while, upon increasing...

Mobility anisotropy in the herringbone structure of asymmetric Ph-BTBT-10 in solution sheared thin film transistors

“…[23][24][25][26][27][28] The crystal arrangement and the morphology of organic semiconductor thin films have been found to be dependent on the substrate, 6,29 solvent and solution concentration, 30 temperature 31 and coating deposition parameters. 9,23,[32][33][34] The use of solution shearing deposition techniques has been shown to be a promising approach to obtain high performing thin film OFETs at low cost and on large areas. In these cases, often small molecule organic semiconductors are blended with a binding insulating polymer, such as polystyrene, to enhance the solution viscosity and favour the surface wetting and the formation of a homogenous film.…”

Bulk and Surface‐Mediated Polymorphs of Bio‐Inspired Dyes Organic Semiconductors: The Role of Lattice Phonons in their Investigation

“…Given the important role played by the interface in phase formation, due to the correlation between molecular packing and charge transport properties in organics, [89][90][91][92] the study of growth processes of highly ordered films for device application is the subject of ongoing research. [93][94][95][96] In this, the knowledge of the film characteristics benefits from the use of a variety of techniques and Raman is undoubtedly one such tool.…”

“…This information is especially important due to the detrimental effect of a phase mixing on the charge transport. [90,92,98,99] Specular X-ray scattering measurements of nanometric indigo films vapor deposited on Si/SiO 2 [50] yielded only two reflections, which could be assigned to weak crystallographic orientations along different planes of either form A or B, [50] thus not providing a clear indication on the phase composition. Similarly, vapor films grown on various substrates [100] displayed a sharp single diffraction peak, which was taken as an indication of a crystalline texture with a preferential orientation, without however reporting to which polymorph it should be attributed.…”

“…The bar-assisted meniscus shearing (BAMS) growth method is the effective technique which has allowed the morphology and polymorphism in thioindigo films to be controlled. [90,91,102,103] Figure 9a reports the scheme of the BAMS setup used for the preparation of the films. The compound solution, forming a meniscus between a metallic bar and the substrate, is dragged along the heated interface at a controlled speed, while the solvent evaporates giving rise to a homogenous deposition.…”

Precursor polymorph determines the organic semiconductor structure formed upon annealing

“…[4][5][6] Thus, the capability to modify the crystal phase offers the chance to control the mobility of the charge carriers, and this may be achieved in thin films by selection of the growing conditions or by post-deposition processing. 5,[7][8][9] In the search of functional materials with low environmental impact, as recommended by the green policies, 10 pigments belonging to the class of the indigoids [11][12][13] were found to possess attractive features, displaying balanced, albeit not high, ambipolar field effect charge transport coupled with operational stability at ambient conditions. 14 All elements of the class also exhibit extended polymorphism, with phases which are metastable in the processing conditions getting stabilized at surface growths or forming genuine thin film phases.…”