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A novel aggregation-induced emission active molecules (TP-Cn-PETPE, n = 4 and 10) were synthesized, which contain a tetraphenylethene derivative as the emission active moiety, a pentahexyloxytriphenylene core as the mesogenic unit and an alkoxy spacer. Experimental results revealed that these two compounds both had AIE properties, even in the liquid state at room temperature. While only TP-C4-PETPE showed a monotropic liquid crystal phase upon heating. In addition, these two compounds were fully characterized by 1H and 13C NMR, IR, EA and MS. [ABSTRACT FROM AUTHOR]

The synthesis and liquid crystalline properties of some new triphenylene discotics bearing pendant acrylate groups are described. Mesophase behaviour is found to be sensitive to the number and position of substituents, the linking chain length, and to change between acrylate and methacrylate termini. Investigation of the isomerically pure triphenylene acrylate and methacrylate derivatives showed that the molecular symmetry also has a modest effect on mesophase behaviour. Unsurprisingly columnar phases are formed only when all substituent chains are of comparable length and methacrylates are far superior to simple acrylate termini, probably due to favourable space filling in the mesophase. [ABSTRACT FROM AUTHOR]

Abstract: An interesting discotic triphenylene derivative, 2,7-biscarbethoxy-3,6,10,11-tetrapentyloxytriphenylene, can be homeotropically aligned on a large scale as a film on single substrates, i.e. the film with one side on the substrate and the other side freestanding. The alignment is achieved in a controlled condition close to a thermodynamic equilibrium state in a liquid crystal phase when interactions at the substrate surface are limited. Phase changing properties of this material are also a key factor in the alignment processes. The aligned structures are observed with an optical microscope. Within a single domain a hexagonal lattice of a d-spacing 16.3Å is confirmed by X-ray diffraction measurement. [Copyright &y& Elsevier]

Abstract: Monohydroxypentaalkoxytriphenylenes are important intermediates for elaboration into complex covalently linked discotic liquid crystal assemblies. An improved, simple synthetic protocol is described that gives rapid access to these precursors in a single step. [ABSTRACT FROM AUTHOR]

Liquid crystal material BTR was employed as regulator to improve hole transport in blend active layer, leading to the optimized performance of photomultiplication type polymer photodetectors. [Display omitted] • BTR with high-crystallinity is used to adjust molecular arrangement in active layers. • Hole mobility is improved by incorporating BTR into active layers. • A new strategy is proposed to optimize performance of PM-PPDs. Photomultiplication type polymer photodetectors (PM-PPDs) were achieved with PBDB-T:BTPV-4F (98:2, wt/wt) as blend active layer based on a sandwich structure. Isolated electron traps are formed due to the rather less BTPV-4F surrounded by PBDB-T in blend active layers. Trapped electrons in BTPV-4F near Al electrode will induce interfacial band bending for hole tunneling injection into blend active layers. The tunneling injected holes will be transported along the channels formed by PBDB-T in blend active layers, photomultiplication phenomenon will be obtained when the number of holes crossing through blend active layers is larger than that of incident photons per unit time. Liquid crystal material BTR was selected as regulator to adjust PBDB-T molecular arrangement for improving hole mobility in blend active layers, leading to optimized performance of PM-PPDs. Optimal PM-PPDs were obtained with PBDB-T:BTR:BTPV-4F (89:9:2, wt/wt/wt) as blend active layer. The external quantum efficiency (EQE) values of optimal PM-PPDs are 1.5 times that of PM-PPDs based on PBDB-T:BTPV-4F (98:2, wt/wt) in the whole spectral response range under −10 V applied bias. The EQE of optimal PM-PPDs can be markedly improved by increasing applied bias, which is improved from 600% to 19,300% at 660 nm with applied bias increased from −10 to −20 V. The responsivity of optimal PM-PPDs arrives to 102 A W−1 at 660 nm under −20 V applied bias. [ABSTRACT FROM AUTHOR]