Browsing by Author "Chiang, I. -Hung"

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Novel metallo-dendrimers containing various Ru core ligands and dendritic thiophene arms for photovoltaic applications
(2014)
Satapathy, Rudrakanta
;
Ramesh, Mohan
;
Padhy, Harihara
;
Chiang, I. -Hung
;
Chu, Chih-Wei
Three series of supramolecular mono-(i.e., Ru1G1, Ru1G2 and Ru1G3), bis-(i.e., BTRu2G1, BTRu2G2 and BTRu2G3) and tris-(i.e., TPARu3G1, TPARu3G2 and TPARu3G3) Ru-based dendritic complexes were synthesized. Their photophysical and electrochemical properties were investigated. These metallo-dendritic complexes covered a broad absorption range of 250-750 nm with optical bandgaps of 1.51-1.86 eV. The energy levels of the metallo-dendrimers can be effectively adjusted not only by different generations of dendritic thiophene arms but also by their pi-conjugated core ligands bearing various electron donor (i.e., triphenylamine) and acceptor (i.e., benzothiadiazole) moieties. Due to the donor-acceptor effect, the bis-Ru-based dendrimers containing a benzothiadiazole electron-acceptor core ligand showed the highest power conversion efficiency (PCE) among these three series of metallo-dendrimers. The tris-Ru-based architecture with a triphenylamine electron-donor core ligand revealed moderate photovoltaic performance. Among the different generations (G1-G3) of dendrimers, the third generation (G3) possessed the highest PCE values in each series of Ru-based dendrimers. Hence, the third generation bis-\'Ru\'-based dendrimer BTRu2G3 blended with PC70BM (1 : 3 w/w) showed the highest PCE value of 0.77% (without the aid of additives or annealing), which is the highest efficiency among all bulk hetero-junction (BHJ) solar cells containing metallo-dendrimers reported to date.
Synthesis and study of hybrid hydrogen-bonded bent-core liquid crystal complexes containing C-60- and Si-based proton donors
(2015-01-01)
Liu, Shih-Hsien
;
Yang, Po-Jen
;
Wei, Chong-Lun
;
Chiang, I. -Hung
;
Liao, Chun-Yen
Novel hydrogen-bonded (H-bonded) C-60- and Si-based bent-core liquid crystal (LC) complexes containing a bent-shaped proton acceptor and C-60- and Si-based single/double armed proton donors were synthesized and mixed to produce hybrid H-bonded LC complexes. The SmCP phases could be introduced in the hybrid LC complexes with a very high C-60-based moiety up to 90 mol%. Among our H-bonded LC complexes, the hybrid LC complexes with low amounts of the C-60-based moiety (<= 24 mol%) possessed the highest spontaneous polarization value (ca. 494 nC cm(-2)), the widest mesophasic range (40.8 degrees C) and the lowest saturated electric field (8.8 V-pp mu m(-1)). Under electric fields of modified triangle waveforms, both series of hybrid H-bonded LC complexes displayed an anti-ferroelectric (AF) to a ferroelectric (FE) polar switching as the C-60-based moiety increased up to 24-50 mol%. Therefore, the hybrid H-bonded LC complexes containing a broad molar ratio (0-90 mol%) of C-60-based moiety revealed a tunable route for the electro-optical applications of C-60-based H-bonded liquid crystals.