Browsing by Author "Hsu, Jhih-Yang"

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Angular-Shaped 4,9-Dialkyl - and -Naphthodithiophene-Based Donor-Acceptor Copolymers: Investigation of Isomeric Structural Effects on Molecular Properties and Performance of Field-Effect Transistors and Photovoltaics
(2015-10-14)
Cheng, Sheng-Wen
;
Chiou, De-Yang
;
Tsai, Che-En
;
Liang, Wei-Wei
;
Lai, Yu-Ying
Two angular-shaped 4,9-didodecyl -aNDT and 4,9-didodecyl -aNDT isomeric structures have been regiospecifically designed and synthesized. The distannylated -aNDT and -aNDT monomers are copolymerized with the Br-DTNT monomer by the Stille coupling to furnish two isomeric copolymers, PNDTDTNT and PNDTDTNT, respectively. The geometric shape and coplanarity of the isomeric -aNDT and -aNDT segments in the polymers play a decisive role in determining their macroscopic device performance. Theoretical calculations show that PNDTDTNT possesses more linear polymeric backbone and higher coplanarity than PNDTDTNT. The less curved conjugated main chain facilitates stronger intermolecular - interactions, resulting in more redshifted absorption spectra of PNDTDTNT in both solution and thin film compared to the PNDTDTNT counterpart. 2D wide-angle X-ray diffraction analysis reveals that PNDTDTNT has more ordered -stacking and lamellar stacking than PNDTDTNT as a result of the lesser curvature of the PNDTDTNT backbone. Consistently, PNDTDTNT exhibits a greater field effect transistor hole mobility of 0.214 cm(2) V-1 s(-1) than PNDTDTNT with a mobility of 0.038 cm(2) V-1 s(-1). More significantly, the solar cell device incorporating the PNDTDTNT:PC71BM blend delivers a superior power conversion efficiency (PCE) of 8.01% that outperforms the PNDTDTNT:PC71BM-based device with a moderate PCE of 3.6%.
Naphthobisthiadiazole-Based Selenophene-Incorporated Quarterchalcogenophene Copolymers for Field-Effect Transistors and Polymer Solar Cells
(2019-03-27)
Cao, Fong-Yi
;
Lin, Fang-Yu
;
Tseng, Cheng-Chun
;
Hung, Kai-En
;
Hsu, Jhih-Yang
In this research, we developed six new selenophene-incorporated naphthobisthiadiazole-based donor-acceptor polymers PNT2Th2Se-OD, PNT2Se2Th-OD, PNT4Se-OD, PNT2Th2Se-DT, PNT2Se2Th-DT, and PNT4Se-DT. The structure-property relationships have been systematically established through the comparison of their structural variations: (1) isomeric biselenophene/bithiophene arrangement between PNT2Th2Se and PNT2Se2Th polymers, (2) biselenophene/bithiophene and quarterselenophene donor units between PNT2Th2Se/PNT2Se2Th and PNT4Se polymers, and (3) side-chain modification between the 2-octyldodecylthiophene (OD)- and 2-decyltetradecyl (DT)-series polymers. The incorporation of selenophene units in the copolymers induces stronger charge transfer to improve the light-harvesting capability while maintaining the strong intermolecular interactions to preserve the intrinsic crystallinity for high carrier mobility. The organic field-effect transistor device using PNT2Th2Se-OD achieved a high hole mobility of 0.36 cm(2) V-1 s(-1) with an on/off ratio of 1.9 x 10(5). The solar cells with PNT2Th2Se-OD:PC71BM exhibited a power conversion efficiency of 9.47% with a V-oc of 0.68 V, an fill factor of 67%, and an impressive J(SC), of 20.69 mA cm(-2).
Side-chain modulation of dithienofluorene-based copolymers to achieve high field-effect mobilities
(2017-04-01)
Lee, Chia-Hao
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Lai, Yu-Ying
;
Hsu, Jhih-Yang
;
Huang, Po-Kai
;
Cheng, Yen-Ju
A ladder-type dithieno[3,2-b: 6,7-b'] fluorene (DTF), where the central fluorene is fused with two outer thiophene rings at its 2,3- and 6,7-junctions, is developed. The pentacyclic DTF monomers were polymerized with dithienodiketopyrrolopyrrole (DPP) acceptors to afford three alternating donor-acceptor copolymers PDTFDPP16, PDTFDPP20, and PDTFDPP32 incorporating different aliphatic side chains (R-1 group at DTF; R-2 group at the DPP moieties). The side-chain variations in the polymers play a significant role in determining not only the intrinsic molecular properties but also the intermolecular packing. As evidenced by the 2-dimensional GIXS measurements, PDTFDPP16 with octyl (R-1) and 2-ethylhexyl (R-2) side chains tends to align in an edge-on pi-stacking orientation, whereas PDTFDPP20 using 2-butyloctyl (R-1) and 2-ethylhexyl (R-2) adopts a predominately face-on orientation. PDTFDPP32 with the bulkiest 2-butyloctyl (R-1) and 2-octyldodecyl (R-2) side chains shows a less ordered amorphous character. The OFET device using PDTFDPP20 with a face-on orientation determined by GIXS measurements achieved a high hole-mobility of up to 5 cm(2) V-1 s(-1). The high rigidity and coplanarity of the DTF motifs play an important role in facilitating intramolecular 1-dimensional charge transport within the polymer backbones. The implementation of main-chain coplanarity and side-chain engineering strategies in this research provides in-depth insights into structure-property relationships for guiding development of high-mobility OFET polymers.
Synthesis and Isomeric Effects of Ladder-Type Alkylated Terbenzodithiophene Derivatives
(2016-03-18)
Chen, Yung-Lung
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Hsu, Jhih-Yang
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Lin, Fang-Yu
;
Lai, Yu-Ying
;
Chou, Hsiao-Chieh
A new class of heptacyclic ladder-type terbenzodithiophene (TBDT) structures merging three fused benzodithophenes was developed. Two TBDT conjugated isomers, named as syn-TBDT and anti-TBDT, where the two thienyl rings in the outmost BDT units are in the syn- and anti-fashion, are designed. Two decyl groups are introduced to their 6,13 and 7,14-positions to form four isomeric 6,13-syn-TBDT, 7,14-syn-TBDT, 6,13-anti-TBDT, and 7,14-anti-TBDT structures which are constructed by the DBU-induced 6-benzannulation involving propargyl-allenyl isomerization of the dieneyne moieties in the corresponding precursors followed by 6 pi-electro-cyclization/aromatization, while isomeric TD-syn-TBDT and TD-anti-TBDT with four decyl groups substituted at 6,7,13,14-positions are synthesized via palladium-catalyzed dialkylacetylene insertion/C-H arylation of the corresponding iodobiaryl precursors. The intrinsic properties can be modulated by molecular manipulation of the main-chain and side-chain isomeric structures. anti-TBDT derivatives exhibit higher melting points, larger bandgaps, stronger intermolecular interactions, and higher mobility than the corresponding syn-TBDT analogues. These molecules can be further utilized as building blocks to make various TBDT-based materials for optoelectronic applications.
Synthesis and Molecular Properties of Two Isomeric Dialkylated Tetrathienonaphthalenes
(2016-02-05)
Chang, Shao-Ling
;
Lu, Chih-Wen
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Lai, Yu-Ying
;
Hsu, Jhih-Yang
;
Cheng, Yen-Ju
Isomeric 2,8-distannyl 5,11-didodecyl alpha/beta-TTN (1, tetrathienonaphthalene = TTN) and 2,8-didodecyl 5,11-distannyl alpha beta-TTN (2) have been designed and successfully synthesized. The naphthalene core structures in alpha beta-TTNs were constructed by a systematic protocol using PtCl2-catalyzed cyclization followed by oxidative Scholl annulation in good yields. Compared to the one-dimensional naphthodithiophene derivatives, the two-dimensional alpha beta-TTN molecules showed good solubility, extended conjugation, strong absorptivity, and highly coplanar structures. Compounds 1 and 2 were polymerized with a 5,5\'-dibromo-2,2\'-bithiophene-based monomer to afford 2,8-alpha beta-PTTNTT and 5,11-alpha beta-PTTNTT copolymers. 2,8-alpha beta-PTTNTT with the alpha-aNDT moiety in the main chain exhibited a higher hole mobility of 1.26 X 10(-2) cm(2) V-1 s(-1).
Synthesis and side-chain isomeric effect of 4,9-/5,10-dialkylated-beta-angular-shaped naphthodithiophenes-based donor-acceptor copolymers for polymer solar cells and field-effect transistors
(2017-04-21)
Chiou, De-Yang
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Cao, Fong-Yi
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Hsu, Jhih-Yang
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Tsai, Che-En
;
Lai, Yu-Ying
A systematic methodology is developed to construct the angular-shaped beta-form naphthodithiophene (beta-aNDT) core with regiospecific substitution of two alkyl groups at its 4,9-or 5,10-positions via the base-induced double 6 pi-cyclization of dithienyldieneyne precursors, leading to the two isomeric 4,9-beta-aNDT and 5,10-beta-aNDT monomers. It is found that a more curved geometry of the beta-aNDT units intrinsically increases the solubility and thus the solution-processability of the resultant polymers. Therefore, beta-aNDT units are ideal for polymerization with an acceptor-containing monomer without the need for any solubilizing aliphatic side chains, which are considered the insulating portion that jeopardizes charge transport. Based on this consideration, the 4,9- and 5,10-dialkylated beta-aNDT monomers are polymerized with the non-alkylated DTFBT acceptor to afford two P4,9-beta NDTDTFBT and P5,10-beta NDTDTFBT copolymers for head-to-head comparison of the 4,9-inner/5,10-outer isomeric alkylation effect. It is found that 4,9-beta aNDT adopts a twisted conjugated structure due to the intramolecular steric repulsion between the inner branched side chains and the beta-hydrogens on the thiophene rings. The slightly twisted 4,9-beta-aNDT moiety allows P4,9-beta NDTDTFBT to have higher solubility upon polymerization and thus a higher molecular weight, which eventually induces a higher ordered packing structure in the thin film compared to P5,10-beta NDTDTFBT. As a result, P4,9-beta NDTDTFBT exhibits a higher OFET mobility of 0.18 cm(2) V-1 s(-1), and the P4,9-beta NDTDTFBT: PC71BM-based solar cell device also achieves a higher PCE of 7.23%, which is even better than the corresponding P4,9-alpha NDTDTFBT-based device.
Synthesis of a 4,9-Didodecyl Angular-Shaped Naphthodiselenophene Building Block To Achieve High-Mobility Transistors
(2016-07-26)
Tsai, Che-En
;
Yu, Ruo-Han
;
Lin, Fang-Ju
;
Lai, Yu-Ying
;
Hsu, Jhih-Yang
A new tetracyclic 4,9-dialkyl angular-shaped naphthodiselenophene (4,9-alpha-aNDS) was designed and synthesized. The naphthalene core in 4,9-alpha-aNDS is formed by the DBU-induced 6 pi-cyclization of an (E)-1,2-bis(3-(tetradec-1-yn-1-yl)selenophen-2-yl)ethene intermediate followed by the second PtCl2-catalyzed benzannulation. This synthetic protocol allows for incorporating two dodecyl groups regiospecifically at 4,9-positions of the resulting alpha-aNDS. An ordered supramolecular self-assembly formed via noncovalent selenium-selenium interactions with a short contact of 3.5 angstrom was observed in the single-crystal structure of 4,9-alpha-aNDS. The distannylated alpha-aNDS building block was copolymerized with Br-DTFBT and Br-DPP acceptors by Stille cross coupling to form two new donor-acceptor polymers P alpha NDSDTFBT and P alpha NDSDPP, respectively. The bottom-gate/top-contact organic field-effect devices using the PaNDSDTFBT and PaNDSDPP semiconductors accomplished superior hole mobility of 3.77 and 2.17 cm(2) V-1 s(-1), respectively, which are among the highest mobilities reported to date.
Synthesis, molecular and photovoltaic/transistor properties of heptacyclic ladder-type di(thienobenzo)fluorene-based copolymers
(2016)
Lee, Chia-Hao
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Lai, Yu-Ying
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Cao, Fong-Yi
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Hsu, Jhih-Yang
;
Lin, Zong-Liang
We present a facile synthesis method to make a new ladder-type heptacyclic dithienobenzofluorene (DTBF) framework, where the central 2,7-fluorene unit is covalently fastened with two external thiophenes via two C=C bridges. A dieneyne-containing precursor undergoes DBU-induced double benzannulation to regiospecifically introduce two solubilizing 2-octyldodecyl side chains at 5,10-positions of DTBF. The rigid and coplanar Br-DTBF monomer with sufficient solubility was copolymerized with 5,6-difluoro-4,7-bis(5-(trimethylstannyl) thiophen-2-yl) benzo[c][1,2,5] thiadiazole (Sn-DTFBT) and 5,10-bis(5-(trimethylstannyl)thiophen-2-yl)naphtho[1,2-c: 5,6-c\'] bis([1,2,5] thiadiazole) (Sn-DTNT) via Stille coupling to furnish two donor-acceptor copolymers, PDTBFFBT and PDTBFNT, respectively. Their thermal, optical, electrochemical, molecular stacking and photovoltaic properties are investigated. PDTBFNT has a higher molecular weight, smaller optical and electrochemical band gaps, and stronger solid-state packing than PDTBFFBT. DFT calculations were carried out to gain insight into the electronic and structural properties of DTBF and its derivatives. Bulk heterojunction solar devices with the ITO/ZnO/polymers: PC71BM/MoO3/Ag configuration were fabricated. By adding 5 vol% diphenyl ether (DPE) as an additive, PDTBFNT: PC71BM and PDTBFFBT: PC71BM devices achieved the power conversion efficiencies of 5.22% and 2.68%, respectively. The superior efficiency of PDTBFNT over PDTBFFBT is attributed to the better LUMO energy alignment between PDTBFNT and PC71BM and the face-on p-stacking of PDTBFNT in the active layer. Moreover, PDTBFNT exhibited a higher field-effect transistor hole mobility of 1.90 x 10(-2) cm(2) V-1 s(-1) than PDTBFFBT with a value of 3.96 x 10(-3) cm(2) V-1 s(-1).
Thiophene-Vinylene-Thiophene-Based Donor-Acceptor Copolymers with Acetylene-Inserted Branched Alkyl Side Chains To Achieve High Field-Effect Mobilities
(2018-11-13)
Chiou, De-Yang
;
Su, Yen-Chen
;
Hung, Kai-En
;
Hsu, Jhih-Yang
;
Hsu, Tze-Gang
2-Alkyl((1))alkyl((2))-type aliphatic side chains with a branching point position at the C-2-position (such as 2-ethylhexyl or 2-octayldodecyl) have been widely implanted into numerous donor-acceptor conjugated copolymers for solution processable transistors or organic solar cells. However, the tertiary branching site located at the second carbon inevitably imposes steric hindrance that twists the main-chain coplanarity and attenuates interchain interactions. In this research, we developed a new two-dimensonal thiophene-vinylene-thiophene (TVT) derivative where a carbon-carbon triple bond is inserted between the thiophene unit and the 2-octyldodecyl group. This acetylene-incorporated TVT (aTVT) was copolymerized with 5,10-di(thiophen-2-yl)naphtho[1,2-c:5,6-c']bis-([1,2,5]thiadiazole) (DTNT) and 5,6-difluoro-4,7-di(thiophen-2-yl[benzo][1,2,5]thiadiazole (DTFBT) to form the polymers PaTVT-NT and PaTVT-FBT, respectively. PTVT-FBT, without the triple bond, was also prepared for comparison. The insertion of a linear triple bond moves the tertiary carbon away from the main chain to reduce the steric hindrance, thereby improving the main-chain coplanarity and facilitating the interchain interactions. The acetylene-incorporated copolymers show better thermal stability, red-shifted absorption spectra, stronger intermolecular aggregation, lower-lying electron affinity, and much higher solid-state crystallinity. Due to the linear and coplanar polymeric backbone supported by theoretical calculation, PaTVT-NT exhibits high crystallinity and adopts strong stacking with an edge-on orientation in the thin film evidenced by 2D-GIXRD, leading to a high p-type OFET mobility up to 1.27 cm(2) V-1 s(-1) with an on-off ratio of 9.22 X 10(5). This value represents the highest value among the NT-based polymers. PaTVT-FBT also achieved a high mobility of 0.78 cm(2) which greatly outperforms the corresponding nonacetylene PTVT-FBT counterpart. Most importantly, the preparation of 2-alkyl((1))alkyl((2))-acetylenyl side chain is synthetically feasible, which can be easily applied to create new conjugated polymers for high-performance solution-processable optoelectronics.