Electron transporting organic materials with an exceptional large scale homeotropic molecular orientation

2016 ◽  
Vol 18 (12) ◽  
pp. 8554-8560 ◽  
Author(s):  
Huan Zhao ◽  
Zhiqun He ◽  
Min Xu ◽  
Chunjun Liang ◽  
Sandeep Kumar
Keyword(s):  
Charge Carrier ◽  
Molecular Orientation ◽  
Carrier Mobility ◽  
Large Scale ◽  
Organic Materials ◽  
Substrate Surface ◽  
Charge Carrier Mobility ◽  
Anthraquinone Derivative ◽  
Homeotropic Alignment

An electron transporting anthraquinone derivative demonstrated a stable large-scale homeotropic alignment on an open substrate surface, which substantially improved its charge carrier mobility.

scholarly journals Orientation analysis of pentacene molecules in organic field-effect transistor devices using polarization-dependent Raman spectroscopy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Bishwajeet Singh Bhardwaj ◽  
Takeshi Sugiyama ◽  
Naoko Namba ◽  
Takayuki Umakoshi ◽  
Takafumi Uemura ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Charge Carrier ◽  
Molecular Orientation ◽  
Field Effect ◽  
High Performance ◽  
Carrier Mobility ◽  
Field Effect Transistors ◽  
Charge Carrier Mobility ◽  
Orientation Distribution ◽  
High Resolution Technique

Abstract Pentacene, an organic molecule, is a promising material for high-performance field effect transistors due to its high charge carrier mobility in comparison to usual semiconductors. However, the charge carrier mobility is strongly dependent on the molecular orientation of pentacene in the active layer of the device, which is hard to investigate using standard techniques in a real device. Raman scattering, on the other hand, is a high-resolution technique that is sensitive to the molecular orientation. In this work, we investigated the orientation distribution of pentacene molecules in actual transistor devices by polarization-dependent Raman spectroscopy and correlated these results with the performance of the device. This study can be utilized to understand the distribution of molecular orientation of pentacene in various electronic devices and thus would help in further improving their performances.

Estimation of charge carrier mobility in amorphous organic materials using percolation corrected random-walk model

2016 ◽  
Vol 29 ◽  
pp. 50-56 ◽  
Author(s):  
David R. Evans ◽  
Hyunwook S. Kwak ◽  
David J. Giesen ◽  
Alexander Goldberg ◽  
Mathew D. Halls ◽  
...  
Keyword(s):  
Random Walk ◽  
Charge Carrier ◽  
Carrier Mobility ◽  
Organic Materials ◽  
Charge Carrier Mobility ◽  
Random Walk Model

Mesomorphic phthalocyanines, tetraazaporphyrins, porphyrins and triphenylenes as charge-transporting materials

2000 ◽  
Vol 04 (01) ◽  
pp. 88-102 ◽  
Author(s):  
H. EICHHORN
Keyword(s):  
Charge Carrier ◽  
Carrier Mobility ◽  
Charge Carrier Mobility ◽  
Point Of View ◽  
Time Resolved ◽  
Homeotropic Alignment ◽  
Flight Measurements ◽  
High Charge Carrier Mobility ◽  
Very High ◽  
Potential Use

The columnar mesomorphism of triphenylene-, phthalocyanine-, tetraazaporphyrin- and porphyrin-based compounds is briefly reviewed and the potential use of this particular supramolecular structure for charge-conducting devices is discussed. Suitably substituted triphenylenes exhibit ideal material properties for photoconducting devices, and well-aligned layers have been shown to give a very high charge carrier mobility of 0.1 × 10-4 m 2 V -1 s -1 (time-of-flight measurements). From a molecular point of view, porphyrin systems should be superior to triphenylenes, but the properties of their mesophases do not support the advantageous homeotropic alignment of the columnar stacks. However, pulse radiolysis time-resolved microwave conductivity measurements revealed the highest charge carrier mobility value of 0.28 × 10-4 m 2 V -1 s -1 for mesomorphic phthalocyanines.

The Influence of Nitrogen Position on Charge Carrier Mobility in Enantiopure Aza[6]helicene Crystals

2018 ◽  
Author(s):  
Francesco Salerno ◽  
Beth Rice ◽  
Julia Schmidt ◽  
Matthew J. Fuchter ◽  
Jenny Nelson ◽  
...  
Keyword(s):  
Solid State ◽  
Charge Carrier ◽  
Carrier Mobility ◽  
Chemical Structure ◽  
Crystal Packing ◽  
Charge Carrier Mobility ◽  
Individual Factor ◽  
Charge Mobility ◽  
Order Of Magnitude ◽  
Small Change

<p>The properties of an organic semiconductor are dependent on both the chemical structure of the molecule involved, and how it is arranged in the solid-state. It is challenging to extract the influence of each individual factor, as small changes in the molecular structure often dramatically change the crystal packing and hence solid-state structure. Here, we use calculations to explore the influence of the nitrogen position on the charge mobility of a chiral organic molecule when the crystal packing is kept constant. The transfer integrals for a series of enantiopure aza[6]helicene crystals sharing the same packing were analysed in order to identify the best supramolecular motifs to promote charge carrier mobility. The regioisomers considered differ only in the positioning of the nitrogen atom in the aromatic scaffold. The simulations showed that even this small change in the chemical structure has a strong effect on the charge transport in the crystal, leading to differences in charge mobility of up to one order of magnitude. Some aza[6]helicene isomers that were packed interlocked with each other showed high HOMO-HOMO integrals (up to 70 meV), whilst molecules arranged with translational symmetry generally afforded the highest LUMO-LUMO integrals (40 - 70 meV). As many of the results are not intuitively obvious, a computational approach provides additional insight into the design of new semiconducting organic materials.</p>

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