Charge transport in phenazine-fused triphenylene discotic mesogens doped with CdS nanowires

Abstract

Herein, we report the synthesis of oleylamine capped CdS nanowires (NWs) and we have dispersed a small optimized amount of these NWs in the Colh phase of a recently synthesized...

Charge Mobility in Discotic Liquid Crystals

“…Triphenylene derivatives still remain the most studied compounds and they have been used to develop new materials, testing new side chains, or new cores [ 191 , 192 , 193 , 194 , 195 , 196 ], to be linked with other cores to prepare dyads and triads [ 67 , 197 , 198 , 199 , 200 ] or materials giving segregate columns [ 201 , 202 ]. Triphenylenes were also doped with nanoparticles or used to prepare blends with other mesogenic molecules [ 203 , 204 , 205 ].…”

“…Triphenylenes were also doped with different kinds of molecule to improve charge mobility or electric conductivity [ 203 , 204 , 205 ]. Khan reported results on a blend of HAT6 and 2,3,6,7,10,11-hexakisdecyloxytriphenylene (HAT10) doped with different amounts (from 0.1 to 5 wt%) of 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), demonstrating an increase of conductivity due to doping [ 205 ].…”

“…Even if they observed a decrease in the core-core distance in the doped mesophase, a small decrease of hole mobility was detected and attributed to the effect of the nanowires on DLC order. However, an increase of electrical conductivity was observed because the CdS nanowires can behave as an n-type dopant [ 204 ]. Mahesh and coworkers studied the effect of doping 2,3,6,7,10,11-hexabutyloxytriphenylene (HAT4) with different concentrations (from 0.5 to 5 wt%) of carbon nanodots.…”

“…Triphenylenes were also doped with different kinds of molecule to improve charge mobility or electric conductivity [203][204][205]. Khan reported results on a blend of HAT6 and [199].…”

Ambipolar Charge Transport Properties of Naphthophenanthridine Discotic Liquid Crystals

“…Thermotropic discotic liquid crystalline materials overcome this restriction through columnar organization, that is, the disc-shaped molecules stack on top of each other to form a one-dimensional column which further occupies various two-dimensional lattices. These mesogenic materials, which are known as one of the delicate phases of matter, exhibit both order and mobility, and the homogeneous domains can be achieved sometimes to a larger length scale which is essentially required for semiconducting devices. − The discovery of discotic liquid crystals by Chandrasekhar et al has motivated research groups around the globe to explore new discogens and study their charge transport character. − Discotic liquid crystals have been used in photoconductive devices due to their high charge carrier mobility. , Generally, the mesogenic stability of discotics and the charge transport property are influenced by the size of the π-conjugated core, the nature of substituents, and the relative positioning of the neighboring molecules. − Recently, nitrogen-containing polycyclic aromatic molecules have drawn enormous interest as n-type semiconductors because of their expanded electron affinity and enhanced π-stacking. − Many reports on nitrogen-fused discotic systems are known to be highly emissive for a broad wavelength range , and device applications. − Our group has previously reported various nitrogen-incorporated discotic systems through ring fusion and ring annulation for their liquid crystallinity and applications. − The charge transport properties of many different discotic derivatives and their nanocomposites have been reported in the literature. − The ambipolar charge transporting molecules are of special interest for organic semiconductors as they enable the fabrication of complementary circuits, OFETs, and OLEDs. − In addition, fine-tuning the energy levels of the HOMO and the LUMO by incorporating substituents may result in desirable charge transport properties . Generally, this type of bipolar transport has been achieved through bulk heterojunctions of donor and acceptor materials as active components , or by introducing different source and drain electrodes to facilitate the charge transport .…”