Browsing by Author "Zhang, Wen-Bin"

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A Supramolecular "Double-Cable" Structure with a 129(44) Helix in a Columnar Porphyrin-C-60 Dyad and its Application in Polymer Solar Cells
(2012-11-01)
Wang, Chien-Lung
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Zhang, Wen-Bin
;
Sun, Hao-Jan
;
Van Horn, Ryan M.
;
Kulkarni, Rahul R.
A novel porphyrin-C-60 dyad (PCD1) is designed and synthesized to investigate and manipulate the supramolecular structure where geometrically isotropic [such as [60]fullerene (C-60)] and anisotropic [such as porphyrin (Por)] units coexist. It is observed that PCD1 possesses an enantiomeric phase behavior. The melting temperature of the stable PCD1 thermotropic phase is 160 degrees C with a latent heat (Delta H) of 18.5 kJ mol(-1). The phase formation is majorly driven by the cooperative intermolecular PorPor and C60C60 interactions. Structural analysis reveals that this stable phase possesses a supramolecular double-cable structure with one p-type Por core columnar channel and three helical n-type C-60 peripheral channels. These double-cable columns further pack into a hexagonal lattice with a = b = 4.65 nm, c = 41.3 nm, alpha = beta = 90 degrees and gamma = 120 degrees. The column repeat unit is determined to possess a 129(44) helix. With both donor (D; Pro) and acceptor (A; C-60) units having their own connecting channels as well as the large D/A interface within the supramoleculassr double-cable structure, PCD1 has photogenerated carriers with longer lifetimes compared to the conventional electron acceptor [6,6]-phenyl-C-61-butyric acid methyl ester. A phase-separated columnar morphology is observed in a bulk-heterojunction (BHJ) material made by the physical blend of a low band-gap conjugated polymer, [poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta [2,1-b;3,4-b']-dithiophene)-alt-4,7-(2,1,3-benzothia-diazole)] (PCPDTBT), and PCD1. With a specific phase structure in the solid state and in the blend, PCD1 is shown to be a promising candidate as a new electron acceptor in high performance BHJ polymer solar cells.
Crystal structure and molecular packing of an asymmetric giant amphiphile constructed by one C-60 and two POSSs
(2014-08-18)
Lin, Ming-Champ
;
Hsu, Chih-Hao
;
Sun, Hao-Jan
;
Wang, Chien-Lung
;
Zhang, Wen-Bin
Based on our recent understanding and development of functionalized molecular nanoparticles (MNPs) as building blocks for constructing various giant molecules, we report our efforts on design and synthesis of an asymmetric giant amphiphile, diBPOSS-C-60, composed of one [60]fullerene (C-60) covalently linked with two isobutyl-functionalized polyhedral oligomeric silsesquioxane (BPOSS) MNPs. Its crystal structure and molecular packing were investigated. The compositional asymmetry between C-60 and BPOSS led to a "sandwich-layered" molecular packing scheme, where a single layer of C-60 is sandwiched between double BPOSS layers: a so-called "one-and-half-layered" structure. Within these layers, the molecules further organized into crystalline arrays. Interestingly, this compound can be viewed as size amplification of a class of atomically thin, two-dimensional layered transition metal dichalcogenides with the "one-and-half-layered" structure. 2014 Elsevier Ltd. All rights reserved.
Crystal structure and molecular packing of an asymmetric giant amphiphile constructed by one C-60 and two POSSs
(2014-08-18)
Lin, Ming-Champ
;
Hsu, Chih-Hao
;
Sun, Hao-Jan
;
Wang, Chien-Lung
;
Zhang, Wen-Bin
Based on our recent understanding and development of functionalized molecular nanoparticles (MNPs) as building blocks for constructing various giant molecules, we report our efforts on design and synthesis of an asymmetric giant amphiphile, diBPOSS-C-60, composed of one [60]fullerene (C-60) covalently linked with two isobutyl-functionalized polyhedral oligomeric silsesquioxane (BPOSS) MNPs. Its crystal structure and molecular packing were investigated. The compositional asymmetry between C-60 and BPOSS led to a "sandwich-layered" molecular packing scheme, where a single layer of C-60 is sandwiched between double BPOSS layers: a so-called "one-and-half-layered" structure. Within these layers, the molecules further organized into crystalline arrays. Interestingly, this compound can be viewed as size amplification of a class of atomically thin, two-dimensional layered transition metal dichalcogenides with the "one-and-half-layered" structure. 2014 Elsevier Ltd. All rights reserved.
Facile Synthesis and Photophysical Properties of SphereSquare Shape Amphiphiles Based on Porphyrin[60]Fullerene Conjugates
(2013-05-01)
Wang, Chien-Lung
;
Zhang, Wen-Bin
;
Yu, Xinfei
;
Yue, Kan
;
Sun, Hao-Jun
Molecules constructed from a combination of zero-dimensional ([60]fullerene (C60)) and two-dimensional (porphyrin (Por)) nanobuilding blocks represent an intriguing category of spheresquare shape amphiphiles. These spheresquare shape amphiphiles possess interesting optoelectronic properties. To efficiently synthesize a large variety of C60Por shape amphiphiles, a facile route based on Steglich esterification was developed. The synthetic strategy enables the preparation of hydroxy-functionalized Por precursors () with high purity in a one-pot procedure. All of the C60Por shape amphiphiles () can be readily synthesized in good yields through subsequent Steglich esterification with a highly soluble carboxylic acid derivative of methanofullerene (). Photophysical studies indicated weak electronic coupling between the C60 and Por moieties and suggest an edge-to-face alignment for the moieties. The fluorescence of electronically excited Por portions of each amphiphile was efficiently quenched, which was indicative of electron transfer from 1Por to the C60 group(s). Increasing the number of C60 groups on the shape amphiphiles led to more pronounced quenching of the Por fluorescence, which indicated the potential for more effective generation of charge-separated species, C60.Por+., from the photoexcited C60Por shape amphiphiles.