Browsing by Author "Hsu, So-Lin"

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A New Pentacyclic Indacenodiselenophene Arene and Its Donor-Acceptor Copolymers for Solution-Processable Polymer Solar Cells and Transistors: Synthesis, Characterization, and Investigation of Alkyl/Alkoxy Side-Chain Effect
(2013-10-08)
Chang, Huan-Hsuan
;
Tsai, Che-En
;
Lai, Yu-Ying
;
Liang, Wei-Wei
;
Hsu, So-Lin
A pentacyclic indacenodiselenophene (IDS) arene was synthesized via intramolecular Friedel-Craft cyclization of the selenophene moieties. This IDS framework was used as a model system to investigate the alkyl/alkoxy side-chain effect by preparing IDS-OCH8 and IDS-C-6, where the side chains on the sp(3) carbon in the cyclopentadienyl ring are 4-octyloxyphenyl groups and 4-hexylphenyl groups, respectively. The SnIDS-OCH8 and Sn-IDS-C-6 monomers were copolymerized with 4,7dibromo-2,1,3-benzothiadiazole (BT), 4,7-diiodo-5,6-difluoro-2,1,3-benzothiadiazole (FBT) and 1,3-dibromothieno[3,4-dpyrrole-4,6-dione (TPD) acceptor monomers by Stil le polycondensation to afford five new IDS-based donor acceptor alternating copolymers, PIDSBT-OCH8, PIDSBTC6) PIDSFBT-OCH8, PIDSFBT-C-6, and PIDSTPD-C-6. Despite the fact that the octyloxy and hexyl side chains play a negligible role in the optical and electrochemical properties of the resulting polymers, the solar cell performance is highly associated with the side chains of the polymers. Under similar device fabrication conditions, the PIDSBT-C-6 and PIDSFBT-C-6-based devices showed much improved efficiencies than the corresponding PIDSBT-OCH8, and PIDSFBT-OCH8-based devices (2.6% and 1.9% vs 3.8% and 3.9%). The improvement is mainly the result of much enhanced J(sc) values. Consistently, PIDSBT-C-6 and PIDSFBT-C-6 exhibited much higher FET hole mobilites than the corresponding PIDSBT-OCH8, and PIDSFBT-OCH8. These results clearly revealed that the 4-hexylphenyl group is a more suitable side chain than the 4-octyloxyphenyl group in the IDS system, and the side-chain dependent mobility of the polymers is the dominating factor to determine the photocurrents and efficiencies of PSCs. PIDSBT-C-6 exhibited a high hole mobility of 0.08 cm(2) V-1 s(-1) and PIDSTPD-C-6:PC71BM (1:4 in wt %)-based solar cell with 5 v% chloronaphthalene (CN) delivered a V-oc of 0.92 V, a J(sc) of 9.77 mA/cm(2), an FF of 51%, and a highest PCE of 4.6%. This work not only discloses a new selenophene-containing ladder-type IDS structure and its copolymers but also provides useful insights into the allcyl/alkoxy side-chain effect for future design of conjugated polymers.
A Pentacyclic Nitrogen-Bridged Thienyl-Phenylene-Thienyl Arene for Donor-Acceptor Copolymers: Synthesis, Characterization, and Applications in Field-Effect Transistors and Polymer Solar Cells
(2012-09-01)
Tseng, Cheng-An
;
Wu, Jhong-Sian
;
Lin, Tai-Yen
;
Kao, Wei-Shun
;
Wu, Cheng-En
A pentacyclic benzodipyrrolothiophene (BDPT) unit, in which two outer thiophene rings are covalently fastened with the central phenylene ring by nitrogen bridges, was synthesized. The two pyrrole units embedded in BDPT were constructed by using one-pot palladium-catalyzed amination. The coplanar stannylated Sn-BDPT building block was copolymerized with electron-deficient thieno[3,4-c]pyrrole-4,6-dione (TPD), benzothiadiazole (BT), and dithienyl-diketopyrrolopyrrole (DPP) acceptors by Stille polymerization. The bridging nitrogen atoms make the BDPT motif highly electron-abundant and structurally coplanar, which allows for tailoring the optical and electronic properties of the resultant polymers. Strong photoinduced charge-transfer with significant band-broadening in the solid state and relatively higher oxidation potential are characteristic of the BDPT-based polymers. Poly(benzodipyrrolothiophene-alt-benzothiadiazole) (PBDPTBT) achieved the highest field-effect hole mobility of up to 0.02 cm2?V-1?s-1. The photovoltaic device using the PBDPTBT/PC71BM blend (1:3, w/w) exhibited a Voc of 0.6 V, a Jsc of 10.34 mA?cm-2, and a FF of 50?%, leading to a decent PCE of 3.08?%. Encouragingly, the device incorporating poly(benzodipyrrolothiophene-alt-thienopyrrolodione) (PBDPTTPD)/PC71BM (1:3, w/w) composite delivered a highest PCE of 3.72?%. The enhanced performance arises from the lower-lying HOMO value of PBDPTTPD to yield a higher Voc of 0.72 V.
Blue electroluminescence enhancement of poly{2,7-(9,9'-dioctylfluorene)-co-4-diphenylamino-4'-bipenylmethylsulfide} incorporating side-chain-tethered gold nanoparticles
(2007-09-24)
Hsu, So-Lin
;
Chou, Chia-Hung
;
Chen, Chen-Ping
;
Wei, Kung-Hwa
;
材料科學與工程學系
Through in situ reduction of a gold precursor, we have tethered gold nanoparticles (An NPs) to the side chains of poly(2,7(9,9'-dioctylfluorene)-co-4-diphenylamino-4'-bipenylmethylsulfide) (PF-DBMS) through its ArSCH3 anchor groups. The presence of 1 wt % of the tethered Au NPs led to a reduction in the degree of aggregation of the polymer chains, resulting in a 50 % increase in its quantum yield. ne electroluminescence of a 1 wt % Au/PF-DBMS device was almost four times higher in terms of its maximum brightness and its full-width-at-half-maximum emission peak was much narrower than that of a pure PF-DBMS device; the presence of a small amount of Au NPs significantly enhances the electron injection and transport and suppresses the photo-oxidation of PF-DBMS.
Carbazole-Based Conjugated Polymers Incorporating Push/Pull Organic Dyes: Synthesis, Characterization, and Photovoltaic Applications
(2010-11-15)
Hsu, So-Lin
;
Chen, Chia-Min
;
Wei, Kung-Hwa
;
材料科學與工程學系
;
Department of Materials Science and Engineering
We have synthesized and characterized two new carbazole-based conjugated polymers, PCDCN and PCDTA, incorporating two strong light-absorbing organic dyes. These polymers exhibit relatively low band gaps (similar to 1.5 eV) and broad absorption ranges (from 300 to 700 nm). We fabricated polymer solar cells incorporating these polymers as donors and [6,6]-phenyl-C(71)-butyric acid methyl ester (PC(71)BM) as the acceptor. At a blending ratio of 1: 4, we obtained power conversion efficiencies, under simulated AM 1.5 (100 mW/cm(2)) conditions, of 2.31% and 2.47% for the PCDCN- and PCDTA-based devices, respectively. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 5126- 5134, 2010
Intramolecular donor-acceptor regioregular poly(3-hexylthiophene)s presenting octylphenanthrenyl-imidazole moieties exhibit enhanced charge transfer for heterojunction solar cell applications
(2008-08-22)
Chang, Yao-Te
;
Hsu, So-Lin
;
Chen, Guan-Yu
;
Su, Ming-Hsin
;
Singh, Thounaojam Avinash
Intramolecular donor-acceptor structures prepared by covalently binding conjugated octylphenanthrenyl-imidazole moieties onto the side chains of regioregular poly(3-hexylthiophene)s exhibit lowered bandgaps and enhanced electron transfer compared to the parent polymer, e.g., conjugation of 90 mol% octylphenanthrenyl-imidazole moieties onto poly(3-hexylthiophene) chains reduces the optical bandgap from 1.91 to 1.80 eV, and the electron transfer probability is at least twice as high as that of pure poly(3-hexylthiophene) when blended with [6,6]-phenyl-C-61-butyric acid methyl ester. The lowered bandgap and the fast charge transfer both contribute to much higher external quantum efficiencies, thus much higher short-circuit current densities for copolymers presenting octylphenanthrenyl-imidazole moieties, relative to those of pure poly(3-hexylthiophene)s. The short-circuit current density of a device prepared from a copolymer presenting 90 mol% octylphenanthrenyl-imidazole moieties is 13.7 mA . cm(-2) which is an increase of 65% compared to the 8.3 mA . cm(-2) observable for a device containing pure poly(3-hexylthiophene). The maximum power conversion efficiency of this particular copolymer is 3.45% which suggest that such copolymers are promising polymeric photovoltaic materials.
Intramolecular Donor-Acceptor Regioregular Poly(hexylphenanthrenyl-imidazole thiophene) Exhibits Enhanced Hole Mobility for Heterojunction Solar Cell Applications
(2009-05-25)
Chang, Yao-Te
;
Hsu, So-Lin
;
Su, Ming-Hsin
;
Wei, Kung-Hwa
;
材料科學與工程學系
PHPIT, a new kind of intramolecular donor-acceptor side-chain-tethered hexyl-phenanthrenyl-imidazole polythiophene, is synthesized. The more balanced electron and hole mobilities and the enhanced visible- and internal-light absorptions in the devices consisting of annealed PHPIT/PCBM blends both contribute to a much higher short-circuit current density, which in turn led to a power conversion efficiency as high as 4.1%.
New Carbazole-Based Conjugated Polymers Containing Pyridylvinyl Thiophene Units for Polymer Solar Cell Applications: Morphological Stabilization Through Hydrogen Bonding
(2011-02-01)
Hsu, So-Lin
;
Chen, Chia-Min
;
Cheng, Yu-Hsin
;
Wei, Kung-Hwa
;
材料科學與工程學系
We have synthesized two conjugated polymers (P1, P2) containing alternating electron-donating and -accepting units, based on N-alkyl-2,7-carbazole, 4,7-di(thiophen-5-yl)-2,1,3-benzothiadiazole and 3-[2-(4-pyridyl)vinyl]thiophene units. These conjugated polymers contained different contents of pyridine units, which were incorporated to form hydrogen bonds with [6,6]-phenyl-C(61)-butyric acid (PCBA). When these hydrogen bonding interactions were present in the polymer thin films, their thermal stability improved; deterioration, which occurred through aggregation of PCBA methyl ester after lengthy annealing times, was also suppressed. The power conversion efficiency of a device incorporating the film featuring hydrogen bonding interactions remained at 75% of the original value after thermal annealing for 5 h at 140 degrees C. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 603-611, 2011
Soluble phenanthrenyl-imidazole-presenting regioregular poly (3-octylthiophene) copolymers having tunable bandgaps for solar cell applications
(2007-11-05)
Chang, Yao-Te
;
Hsu, So-Lin
;
Su, Ming-Hsin
;
Wei, Kung-Hwa
;
材料科學與工程學系
We have used Grignard metathesis polymerization to successfully synthesize a series of regioregular polythiophene copolymers that contain electron-withdrawing and conjugated phenanthrenyl-imidazole moieties as side chains. The introduction of the phenanthrenyl-imidazole moieties onto the side chains of the regioregular polythiophenes increased their conjugation lengths and thermal stabilities and altered their bandgap structures. The bandgap energies, determined from the onset of optical absorption, could be tuned from 1.89 eV to 1.77 eV by controlling the number of phenanthrenyl-imidazole moieties in the copolymers. Moreover, the observed quenching in the photoluminescence of these copolymers increases with the number of phenanthrenyl-imidazole moieties in the copolymers, owing to the fast deactivation of the excited state by the electron-transfer reaction. Both the lowered bandgap and fast charge transfer contribute to the much higher external quantum efficiency of the poly (3-octylthiophene)-side-chain-tethered phenanthrenyl-imidazole than that of pure poly(3-octylthiophene), leading to much higher short circuit current density. In particular, the short circuit current densities of the device containing the copolymer having 80 mol % phenanthrenyl-imidazole, P82, improved to 14.2 mA cm(-2) from 8.7 mA cm(-2) for the device of pure poly(3-octylthiophene), P00, an increase of 62 %. In addition, the maximum power conversion efficiency improves to 2.80 % for P82 from 1.22 % for P00 (pure P30T). Therefore, these results indicate that our polymers are promising polymer photovoltaic materials.
Synthesis, Molecular and Photovoltaic Properties of Donor-Acceptor Conjugated Polymers Incorporating a New Heptacylic Indacenodithieno[3,2-b]thiophene Arene
(2012-12-11)
Chang, Huan-Hsuan
;
Tsai, Che-En
;
Lai, Yu-Ying
;
Chiou, De-Yang
;
Hsu, So-Lin
We have developed a new multifused indacenodithieno[3,2-b]thiophene arene (IDTT) unit where the central phenylene is covalently fastened with the two outer thieno[3,2-b]thiophene (TT) rings, forming two cyclopentadiene rings embedded in a heptacyclic structure. This rigid and coplanar IDTT building block was copolymerized with electron-deficient acceptors, 4,7-dibromo-2,1,3-benzothiadiazole (BT), 4,7-dibromo-5,6-difluoro-2,1,3-benzothiadiazole (FBT) and 1,3-dibromo-thieno[3,4-c]pyrrole-4,6-dione (TPD) via Stifle polymerization, respectively. Because the higher content of the thienothiophene moieties in the fully coplanar IDTT structure facilitates pi-electron delocalization, these new polymers show much improved light-harvesting abilities and enhanced charge mobilities compared to PDITTBT copolymer using hexacyclic diindenothieno[3,2-b]thiophene (DITT) as the donor moieties. The device using PIDTTBT:PC71BM (1:4, w/w) exhibited a decent power conversion efficiency (PCE) of 3.8%. Meanwhile, the solar cell using PIDTTFBT:PC71BM (1:4 in wt %) blend exhibited a greater V-oc value of 0.9 V and a larger J(sc) of 10.08 mA/cm(2), improving the PCE to 4.2%. The enhanced V-oc is attributed to the lower-lying of HOMO energy level of PIDTTFBT as a result of fluorine withdrawing effect on the BT unit. A highest PCE of 4.3% was achieved for the device incorporating PIDTTTPD:PC71BM (1:4 in wt %) blend.
Synthesis, Photophysical and Photovoltaic Properties of Conjugated Polymers Containing Fused Donor-Acceptor Dithienopyrrolobenzothiadiazole and Dithienopyrroloquinoxaline Arenes
(2012-03-27)
Cheng, Yen-Ju
;
Ho, Yu-Ju
;
Chen, Chiu-Hsiang
;
Kao, Wei-Shun
;
Wu, Cheng-En
We have developed two nitrogen-bridged pentacyclic donor-acceptor dithienopyrrolobenzothiadiazole (DTPBT) and dithienopyrroloquinoxaline (DTPQX) arenes where the two outer electron-rich thiophene moieties are covalently fastened with the central electron-deficient benzothiadiazole and quinoxaline cores by two nitrogen bridges. These rigid and coplanar DTPBT and DTPQX building blocks were copolymerized with fluorene (F), carbazole (C) and cyclopentadithiophene (CPDT) units via Suzuki or Stifle coupling polymerization to afford six new alternating copolymers PFDTPBT, PCDTPBT, PCPDTDTPBT, PFDTPQX, PCDTPQX and PCPDTDTPQX, respectively. The nitrogen bridges not only planarize the structure to induce stronger intermolecular pi-pi interaction but also play an important role in determining the electronic and photophysical properties of the polymers. The device based on PFDTPQX/PC71BM (1:4, w/w) exhibited a open-circuit voltage (V-oc) of 0.72 V, a short-circuit current (J(sc)) of 8.62 mA/cm(2) and a FF of 0.55 leading to a decent power conversion efficiency (PCE) of 3.40% due to the lower-lying HOMO energy level, and the highest hole-mobility of PFDTPQX