Liquid Crystals of Phthalocyanine-Fullerene Dyads Exhibiting Homeotropic Alignment and Spiranthes-like Supramolecular Structure Useful for Solar Cells

Abstract

A homologous series of the phthalocyanine-fullerene dyads, (CnS)6PcCu-Cm-C60 (4a~g) [(n, m) = (14, 8) (a); (14, 10) (b); (14, 12) (c); (16, 8) (d); (16, 10) (e); (16, 12) (f); (18, 10) (g)], have been synthesized with changing both the chain length of the peripheral alkylthio group (n) and the spacer length (m) between Pc and C60 in order to find out the homologues showing perfect homeotropic alignment at rt. As a result, each of the dyads 4a~g shows perfect homeotropic alignment in their hexagonal ordered columnar (Colho) mesophases and the homologues 4a~c having shorter alylthio chains (n = 14) show perfect homeotropic alignment at rt. Very interestingly, the spherical C60 parts form a helical structure around the column formed by the disk-like Pc parts. This supramolecular structure very resembles spiranthes flower. The spiranthes-like supramolecular structure is compatible with one-dimensional nano-array expecting the high conversion efficiency of solar cells.

Discotic liquid crystals of transition metal complexes 52: Synthesis and homeotropic alignment of liquid crystalline phthalocyanine-fullerene dyad bridged by vanillin

“…At the first time in 2011, we adopted a new monodomain method, together with the conventional polydomain method [15][16][17][18][20][21][22], illustrated in Fig. 6[A] and [B], respectively, and thoroughly established this peak H as a helical pitch in Z-axis direction [23,[30][31][32] from these two different methods. Also by using these methods, we could establish here the helical structure of C 60 moieties around the Pc columns for the present dyad (C 14 S) 6 PcCu-VAN-C 60 (3a).…”

“…To more establish the helical structure of C 60 moieties, we adopted a new monodomain method (like as single crystal method) [23,[30][31][32] together with the conventional polydomain method (like as powder crystal method) [15][16][17][18][20][21][22][23][24][25][26][27][28][29][30][31][32] for the SAXS measurements. From these two different methods, we could thoroughly establish this additional peak as a helical pitch in Z-axis direction, at the first time in 2011 [23,[30][31][32]. The helical structure very resembles spiranthes flowers, so that we named this unique structure as "spiranthes-like supramolecular structure" [31,32].…”

“…From these two different methods, we could thoroughly establish this additional peak as a helical pitch in Z-axis direction, at the first time in 2011 [23,[30][31][32]. The helical structure very resembles spiranthes flowers, so that we named this unique structure as "spiranthes-like supramolecular structure" [31,32]. On the other hand, in 2010-11 Imahori and Shimizu joint research group also reported the helical structure of C 60 moieties in a Pc-C 60 dyad [19,24,25].…”

“…In our recent works, we have successfully synthesized novel dyads, (C n S) 6 PcCu-C m -C 60 (2a-g) (Fig. 2[A]), exhibiting perfect homeotropic alignment [31,32]. The donor part of hexakisalkylthio-substituted PcCu, (C n S) 6 PcCu-, could be synthesized in much shorter synthetic route than that of the previous hexakis(di-m, p-dialkoxyphenoxy)-substituted PcCu part, [(C n O) 2 PhO] 6 PcCu-, (Fig.…”

Metal Phthalocyanine−Fullerene Dyads: Promising Lamellar Columnar Donor−Acceptor Liquid Crystal Phases

“…Phthalocyanines and porphyrins, which show absorption of the visible light over a broad portion of the solar spectrum and are well known discotic mesogens with high charge carrier mobilities, have been subsequently attached to the broadly used, excellent electron acceptor, fullerene C60 . Many of these systems have been claimed to be columnar liquid crystals with helically arranged fullerenes in the periphery . High ambipolar and balanced hole and electron mobilities, long‐lived charge separated states, and facile homeotropic alignment have been reported .…”