Using Deposition Rate and Substrate Temperature to Manipulate Liquid Crystal-Like Order in a Vapor-Deposited Hexagonal Columnar Glass

Abstract

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Controlling the Columnar Order in a Discotic Liquid Crystal by Kinetic Arrest of Disc Tumbling

“…In addition to the q 1 peak, weaker peaks are seen at 0.71 and 0.82 Å −1 , corresponding to higher-order diffractions of hexagonally packed columns at 3 q 1 and 2q 1 , respectively. 22,23 The weak higher-order diffractions indicate a nearly sinusoidal intercolumn density modulation. In addition to columnar order, Kelber et al have observed the π stacking order in this system, giving rise to a scattering peak at 1.8 Å −1 and corresponding to a real-space distance of 3.5 Å.…”

“…22 Bishop et al studied the glasses of PNP prepared by PVD and found that the columnar order in thin films can be systematically tuned by the deposition temperature and deposition rate. 23 The system offers a large temperature window between T Col/I and the glass transition temperature to allow the development of columnar order, a useful feature for testing our hypothesis.…”

Vapor-Deposited Thin Films: Studying Crystallization and α-relaxation Dynamics of the Molecular Drug Celecoxib

“…For instance, the rate of material deposition affects the structural anisotropy, thermal stability, and density of the vapor-deposited glass. 22 , 27 , 28 Likewise, the temperature of the substrate ( T sub ) during deposition can modify the surface equilibration kinetics, stability, molecular orientation, and many others. 11 , 16 , 29 − 35 Focusing on the deposition rate, especially around 0.5 nm s –1 , the molecules are said to obtain enough time for the configurational sampling, allowing high density and stability.…”

Deep Blue Fluorescent Material with an Extremely High Ratio of Horizontal Orientation to Enhance Light Outcoupling Efficiency (44%) and External Quantum Efficiency in Doped and Non-Doped Organic Light-Emitting Diodes

“…Figure a,b illustrates the 2D-GIWAXS results of an AnB4Ph neat thin film and the calculated order parameter ( S GIWAXS ) of 0.61 for a ππ stacking along the normal direction to the substrate. Here, when S GIWAXS = + 1, the molecules line up on the substrate horizontally; an order parameter of S GIWAXS = −0.5 corresponds to vertically oriented molecules. , A 0.61 for AnB4Ph neat films is one of the highest reported S GIWAXS for materials applied in OLEDs, considering most of them have S GIWAXS values less than 0.3. ,,− Such a S GIWAXS implies that molecules of AnB4Ph are predominately aligned horizontally on the substrate. In addition, the results of 2D-GIWAXS show that the d -spacing of AnB4Ph ππ stacking is around 5.1 Å, which matches reasonably well with the results of the single-crystal X-ray structure of AnB4Ph (Figure c), that is, 4.95 Å between the mean plane comprising molecular array.…”