Browsing by Author "Prakoso, Suhendro Purbo"

Now showing 1 - 5 of 5

Accessing pi-expanded heterocyclics beyond dibenzothiophene: Syntheses and properties of phenanthrothiophenes
(1970-01-01)
Venkateswarlu, Samala
;
Prakoso, Suhendro Purbo
;
Kumar, Sushil
;
Tao, Yu-Tai
;
應用化學系
A series of phenanthrothiophenes are designed and synthesized from polyarylthiophenes through regioselective Scholl reactions in one step using iron chloride as catalyst. The molecular structures of these heteroarenes displayed multiple twisted fjords, which perturb the shapes of the polycyclic frameworks to pack in slipped to near-perfect face-to-face styles in parallel or antiparallel packings. Field-effect transistor devices using single crystals of 6,12-difluorodiphenanthro[9, 10-b:9 ', 10 ']thiophene gave a hole mobility of 0.22 cm(2) V-1 s(-1).
Benzophenanthrothiophenes: Syntheses, Crystal Structures, and Properties
(2019-09-06)
Venkateswarlu, Samala
;
Prakoso, Suhendro Purbo
;
Kumar, Sushil
;
Kuo, Ming-Yu
;
Tao, Yu-Tai
A new class of polycyclic heteroarenes based on benzo[3,4]phenanthro[1,2-b]benzo[3,4]phenanthro[2,1-d]thiophene (BPBPT) was prepared from polyaryl thiophenes via regioselective Scholl reactions. The molecular frameworks of these compounds exhibited twisted bridges and near-cofacial packing motifs with oppositely or parallel pi-stacked structures depending on the substituents on the periphery. Theoretical calculation of electronic coupling and charge mobility was carried out on the basis of the single-crystal structures. Single crystals of selected benzophenanthrothiophenes were used in p-channel field-effect transistor device fabrication, from which the highest mobility was measured as 2.03 cm(2) V-1 s(-1) from Flu-BPBPT.
Fabrication of Ag2O/TiO2 composites on nanographene platelets for the removal of organic pollutants: Influence of oxidants and inorganic anions
(2019-06-30)
Saleh, Rosari
;
Taufik, Ardiansyah
;
Prakoso, Suhendro Purbo
;
應用化學系
;
Department of Applied Chemistry
Ternary Ag2O/TiO2/nanographene platelet (Ag2O/TiO2/NGP) composites containing various amounts of NGP were synthesized using a microwave-assisted method and were used as catalysts for degradation of organic dyes in aqueous solution. The composites were characterized by various methods, and their photocatalytic performance was systematically investigated with respect to degradation of methylene blue. Compared with pure TiO2 and Ag2O nanoparticles as well as Ag2O/TiO2 composites, the Ag2O/TiO2/NGP composites exhibited superior photocatalytic performance in the UV and visible light range. The results also indicated that Ag2O/TiO2/NGP composites could be used as efficient broad-spectrum catalysts for the removal of several dye contaminants in aqueous solutions. The correlation between photocatalytic mechanism and physical properties of the catalysts was discussed. The effects of the addition of hydrogen peroxide (H2O2) and persulfate on MB degradation were also investigated. Photocatalytic efficiency was noticeable in the presence of both oxidizers. Because inorganic anions are common substances in natural water, their influence was also evaluated. They were found to inhibit the catalytic activity of Ag2O/TiO2/NGP composites. Their effectiveness in inhibiting photocatalytic degradation of MB was CO32- > NO3- > HPO4- > Cl- > SO42-.
n-Type Thin-Film Transistors Based on Diketopyrrolopyrrole Derivatives: Role of Siloxane Side Chains and Electron-Withdrawing Substituents
(2020-01-08)
Prakoso, Suhendro Purbo
;
Kumar, Sushil
;
Wu, San-Lien
;
Ciou, Guan-Ting
;
Ke, Yao-Jin
The physical properties, packing, morphology, and semiconducting performance of a planar pi-conjugated system can be effectively modified by introducing side chains and substituent groups, both of which can be complementary to the pi framework in changing the intermolecular association, frontier molecular orbital energy, optical band gap, and others. We herein show that installation of end-capped electron-withdrawing groups (EWGs), such as dicyanovinyl (-DCV), 3-ethylrhodanine (-RD), and 2-(3-oxo-indan-1-ylidene)-malononitrile (-INCN), together with siloxane side chains to the backbones of dithienyldiketopyrrolopyrrole (DPPT), such as DPPT-Si-DCV, DPPT-Si-RD, and DPPT-Si-INCN, can greatly improve its solubility, air stability, and film morphology to serve as an n-channel in thin-film transistor fabrication. The EWGs attached to the DPPT core narrowed the optical band gap (E-g(opt)) and changed the highest occupied molecular orbital and the lowest unoccupied molecular orbital energies (E-HOMO and E-LUMO), making them suitable for n-channel field-effect transistor (FET) applications. The benefits of introducing siloxane side chains to the DPPT core include enhanced solubility, low crystallization barrier, enantiotropic phase behavior, and much improved FET performance. The DPPT-Si-INCN film displayed low-lying HOMO (-5.82 eV) and LUMO (-4.60 eV) energy levels and an optical band gap as low as 1.22 eV, all of which suggest that this derivative can be quite resistant toward aerial oxidation. Thin films of these derivatives were prepared by the solution-shear method. A comparison of the solution-sheared films indicated that the molecular packing motif of DPPT-Si-INCN film was somehow different from that of DPPT-Si-DCV and DPPT-Si-RD, in which the pi-pi stacking tended to align orthogonally to the shearing direction. This specific pi-pi stacking alignment could have an impact on the electron mobility (mu(e)) values in transistors based on the solution-sheared films.
Self-Assembly Behavior of Dendritic Liquid Crystals and its Implications in the Packing Structure of Functional Molecular Nanoparticles
(2018-03-01)
Wang, Chien-Lung
;
Prakoso, Suhendro Purbo
;
Wu, San-Lien
;
應用化學系
;
Department of Applied Chemistry
In this mini-review, the self-assembly characteristics of dendritic liquid crystals (LCs) are summarized. By studying and comparing the mesomorphic behavior of dendritic LCs with various core units and peripheral mesogenic units, their packing principle is established. It is found that the chirality, connecting position, and curvature of the peripheral mesogenic units play significant roles in the resulting self-assembly structures of dendritic LCs, whereas the core symmetry and strength of intramolecular interaction affect the geometry and conformational preferences of the dendritic LCs. This fundamental knowledge gives useful guidelines to predict the self-assembly behaviors of novel functional molecular nanoparticles, which share very similar molecular architecture with dendritic LCs.