Browsing by Author "Cheng, Sheng-Wen"

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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
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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%.
Angular-Shaped 4,9-Dialkylnaphthodithiophene-Based Donor-Acceptor Copolymers for Efficient Polymer Solar Cells and High-Mobility Field-Effect Transistors
(2015-04-14)
Cheng, Sheng-Wen
;
Tsai, Che-En
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Liang, Wei-Wei
;
Chen, Yung-Lung
;
Cao, Fong-Yi
Although the tetracyclic angular-shaped naphthodithiophenes (aNDTs) derivatives are an emergent building block for constructing promising semiconductor conjugated polymers, the absence of aliphatic side chains as solubilizing groups on the aNDTs greatly restricted their further application toward polymer synthesis. To create a new class of aNDT-based polymers for widespread applications in solution-processable OFETs and PSCs, side-chain engineering of the aNDT-based structures plays a pivotal role in improving solubility and optimizing electronic/steric properties associated with the resultant solar cell characteristics. In this research, we developed an efficient and straightforward methodology to construct the angular naphthodithophene core with regiospecific introduction of two aliphatic chains at its 4,9-positions via a base-induced double 6p-cyclization. For the first time, the corresponding 2,7-distannylated-4,9-dialkylated aNDT monomers were polymerized with FBT and DPP acceptors to make two new PaNDTDTFBT and PaNDTDPP donor-acceptor copolymers. The photovoltaic devices based on the PaNDTDTFBT:PC71BM blend not only showed a promising PCE of 6.52% with conventional configuration but also achieved a higher PCE of 6.86% with inverted configuration. Moreover, PaNDTDPP with strong intermolecular interaction achieved a high FET hole mobility of 0.202 cm(2) V-1 s(-1).
Diindenothieno[2,3-b]thiophene arene for efficient organic photovoltaics with an extra high open-circuit voltage of 1.14 ev
(2012)
Cheng, Yen-Ju
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Cheng, Sheng-Wen
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Chang, Chih-Yu
;
Kao, Wei-Shun
;
Liao, Ming-Hung
We report a novel diindenothieno[2,3-b]thiophene ladder-type hexacyclic arene for constructing a donor-acceptor copolymer PDITTDTBT. A device based on PDITTDTBT:PC71BM exhibited a high V-oc of 0.92 V with an impressive PCE of 5.8%, while a PDITTDTBT:DMPCBA-based device showed an extra high V-oc of 1.14 V.
Donor-acceptor conjugated polymers based on multifused ladder-type arenes for organic solar cells
(2015-03-07)
Wu, Jhong-Sian
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Cheng, Sheng-Wen
;
Cheng, Yen-Ju
;
Hsu, Chain-Shu
;
應用化學系
Harvesting solar energy from sunlight to generate electricity is considered as one of the most important technologies to address the future sustainability of humans. Polymer solar cells (PSCs) have attracted tremendous interest and attention over the past two decades due to their potential advantage to be fabricated onto large area and light-weight flexible substrates by solution processing at a lower cost. PSCs based on the concept of bulk heterojunction (BHJ) configuration where an active layer comprises a composite of a p-type (donor) and an n-type (acceptor) material represents the most useful strategy to maximize the internal donor-acceptor interfacial area allowing for efficient charge separation. Fullerene derivatives such as [ 6,6]-phenyl-C-61or 71-butyric acid methyl ester (PCBM) are the ideal n-type materials ubiquitously used for BHJ solar cells. The major effort to develop photoactive materials is numerously focused on the ptype conjugated polymers which are generally synthesized by polymerization of electron-rich donor and electron-deficient acceptor monomers. Compared to the development of electron-deficient comonomers (acceptor segments), the development of electron-rich donor materials is considerably flourishing. Forced planarization by covalently fastening adjacent aromatic and heteroaromatic subunits leads to the formation of ladder-type conjugated structures which are capable of elongating effective conjugation, reducing the optical bandgap, promoting intermolecular pi-pi interactions and enhancing intrinsic charge mobility. In this review, we will summarize the recent progress on the development of various well-defined new ladder-type conjugated materials. These materials serve as the superb donor monomers to prepare a range of donor-acceptor semiladder copolymers with sufficient solution-processability for solar cell applications.
Formation of Nanostructured Fullerene Interlayer through Accelerated Self-Assembly and Cross-Linking of Trichlorosilane Moieties Leading to Enhanced Efficiency of Photovoltaic Cells
(2013-06-25)
Liang, Wei-Wei
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Chang, Chih-Yu
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Lai, Yu-Ying
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Cheng, Sheng-Wen
;
Chang, Huan-Hsuan
A new cross-linkable fullerene material, bis(2-(trichlorosilyl)propyl)-malonate C-60 (TSMC), functionalized with two trichlorosilane groups, was easily synthesized by Pt-catalyzed olefin hydrosilylation. By making use of facile hydrolysis of the trichlorosilyl moieties, TSMC can be spontaneously self-assembled and cross-linked on the TiOx surface by a simple spin-coating processing without the aid of photoirradiation or post-thermal treatments. The rapid formation of self-assembled and crosslinked TSMC (SA-C-TSMC) effectively passivates the residual hydroxyl groups on the TiOx surface. More significantly, the solvent-resistant TSMC network features a nanostructured surface to provide extra charge-generating interfacial area and straight electron transport pathways. The device (ITO/TiOx/SA-C-TSMC/P3HT:PC61BM (1:1, w/w)/PEDOT:PSS/Ag) with this C-60 interlayer exhibited an efficiency of 3.9% which greatly outperformed the device without this layer. Furthermore, the strategy can also be effectively applied to the device (ITO/TiOx/PDITTDTBT:PC71BM(1:4, w/w)/MoOx/Ag) incorporating a conjugated polymer, poly(diindenothiophene-alt-dithienylbenzothiadizole) copolymer (PDITTDTBT). This device delivered a high efficiency of 5.8% which represents a 35% enhancement over the device without SA-C-TSMC. This new generation of trichlorosilane-based fullerene offers an easy and accelerated processing technique to produce efficient and cost-effective inverted solar cells.
Synthesis and Molecular Properties of Four Isomeric Dialkylated Angular-Shaped Naphthodithiophenes
(2013-10-18)
Cheng, Sheng-Wen
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Chiou, De-Yang
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Lai, Yu-Ying
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Yu, Ruo-Han
;
Lee, Chia-Hao
A new strategy to synthesize 4,9- and 5,10-dialkylated alpha-aNDTs as well as 4,9- and 5,10-dialkylated beta-aNDTs is described. Four isomeric precursors with different dithienyl-ene-diyne arrangements undergo base-induced double 6 pi-cyclization to construct the central naphthalene cores, leading to the formation of the regiospecific products. These 2,7-distannylated dialkylated aNDT-based monomers can be used for Stille cross-coupling to produce promising conjugated materials for various optoelectronic applications.
Synthesis and Molecular Properties of Tricyclic Biselenophene-Based Derivatives with Nitrogen, Silicon, Germanium, Vinylidene, and Ethylene Bridges
(2014-11-07)
Pao, Yu-Chieh
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Chen, Yung-Lung
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Chen, Yen-Ting
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Cheng, Sheng-Wen
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Lai, Yu-Ying
A new class of biselenophene-based materials including an sp(3)-silicon-bridged diselenosilole (DSS), an sp(3)-germanium-bridged diselenogermole (DSG), and an sp(3)-nitrogen-bridged diselenopyrrole (DSP) as well as an sp(2)-vinylidene-bridged dicyanodiselenofulvene (CDSF), a diacetylenediselenofulvene (ADSF), and a dioctylethylene-bridged benzodiselenophene (BDS) have been successfully synthesized and characterized. The bridging moieties play an important role in determining the optical and electrochemical properties. The six brominated derivatives are ready to construct various biselenophene-based conjugated materials with tunable properties for organic photovoltaics and field effect transistors.
Synthesis and Supramolecular Assembly of Pentacyclic Dithienofluorene and Diselenophenofluorene Derivatives
(2014-02-07)
Lee, Chia-Hao
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Lai, Yu-Ying
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Cheng, Sheng-Wen
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Cheng, Yen-Ju
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應用化學系
2,7-Diiodo-3,6-dibromofluorene and 2,7-dichloro-3,6-dibromofluorene have been successfully synthesized. The two key intermediates enable us to implement a regioselective Sonogashira reaction followed by intramolecular thiolate/acetylene cyclization, forming two regiospecific pentacyclic dithieno[2,3-b:7,6-b']fluorene (2,7-DTF) and dithieno[3,2-b:6,7-b']fluorene (3,6-DTF) isomeric molecules, respectively. By using a similar strategy, selenophene-based diselenopheno[2,3-b:7,6-b']fluorene (2,7-DSF) as well as diselenopheno[3,2-b:6,7-b'] fluorene (3,6-DSF) were also prepared. The isomeric and sulfur/selenium effects determine the optical, electrochemical, and orbital properties. X-ray crystallography revealed that 2,7-DTF and 3,6-DTF molecules assemble into supramolecular helical structures.
Synthesis of a 4,9-Didodecyl Angular-Shaped Naphthodiselenophene Building Block To Achieve High-Mobility Transistors
(2016-07-26)
Tsai, Che-En
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Yu, Ruo-Han
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Lin, Fang-Ju
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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, photophysical and photovoltaic properties of a new class of two-dimensional conjugated polymers containing donor-acceptor chromophores as pendant groups
(2013)
Lai, Yu-Ying
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Cheng, Yen-Ju
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Chen, Chiu-Hsiang
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Cheng, Sheng-Wen
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Cao, Fong-Yi
A new design for constructing two-dimensional conjugated copolymers with the D(1)A(D-2) repeating pattern (A: acceptor, D-1: donor 1, D-2: donor 2; molecules enclosed in parentheses are pendant groups.), is proposed. D-1 and A are employed to construct the linear main-conjugated polymer chain and D-2 is situated at the conjugated side chains connected to A. We designed and synthesized a series of D-1-A(D-2)-type copolymers, in which D-1 = diindeno[1,2-b: 2',1'-d]-thiophene (DIDT) or fluorene (F), A(D-2) = bis-[4-(dioctylamino)-phenyl] quinoxaline (DOAQX) or bis-[4-(dioctylamino)-phenyl] thieno[3,4-b]-pyrazine (DOATP), and D-2 = N,N-dioctylanilines. The resultant copolymers, PDIDTDOAQX, PFDOAQX, PDIDTDOATP and PFDOATP, possess at least two strong ICT absorptions, thus resulting in better light harvesting. Their optical and electronic properties were thoroughly investigated experimentally and computationally. Bulk heterojunction photovoltaic cells on the basis of ITO/PEDOT: PSS/polymer: PC71BM/Ca/Al configuration were fabricated and characterized. The photovoltaic performances of the devices incorporating these polymers follow the sequence: PDIDTDOAQX > PFDOAQX > PDIDTDOATP > PFDOATP, which is in good agreement with the magnitude of their hole-mobilities.
Triarylamine-based crosslinked hole-transporting material with an ionic dopant for high-performance PEDOT:PSS-free polymer solar cells
(2015-01-01)
Tsai, Che-En
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Liao, Ming-Hung
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Chen, Yung-Lung
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Cheng, Sheng-Wen
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Lai, Yu-Ying
A triarylamine-based material DVTPD containing two styryl groups has been developed. Upon isothermal heating at 180 degrees C for 30 min, DVTPD can be thermally cross-linked to form a solvent-resistant layer to realize the fabrication of solution-processed multilayer devices. The crosslinked DVTPD (denoted as X-DVTPD) layer possesses not only hole-collecting ability (HOMO = -5.3 eV) but also electron-blocking capability (LUMO = -2.2 eV). By incorporation of an ionic dopant, 4-isopropyl-4\'-methyldiphenyliodonium tetrakis(pentafluorophenylborate) (DPITPFB), into the X-DVTPD material (1 : 10 in wt%), a favourable morphology of the dopant/matrix layer was formed and the hole-mobility is significantly improved by three orders of magnitude compared to its non-doped state. This DPITPFB : X-DVTPD (1 : 10 in wt%) layer was employed as the hole-transporting layer to fabricate polymer solar cell devices (PSCs). The E-HOMO of the polymer in the active layer relative to the E-HOMO of the X-DVTPD (-5.3 eV) governs the hole transportation highly associated with the device performance. The higher-lying E-HOMO (-5.0 eV) of P3HT causes a large energy barrier for the hole transportation at the interface, leading to an unsatisfactory efficiency. The E-HOMO level of the PTB7 copolymer (-5.15 eV) is closer to -5.3 eV. As a result, the PTB7-based device can achieve 80% of the efficiency obtained from the corresponding PEDOT:PSS-based device. Furthermore, the PBDCPDTFBT copolymer has the same E-HOMO (-5.3 eV) with X-DVTPD. Consequently, the PBDCPDTFBT-based device showed a comparable efficiency of 5.3% to the corresponding PEDOT: PSS-based device. More importantly, PNDTDTFBT having the lowest-lying E-HOMO of -5.4 eV exhibits superior performance with a high PCE of 6.64%, outperforming its reference PEDOT: PSS-based device. This simple and useful hole-transporting system integrating the crosslinking and doping strategies to replace PEDOT:PSS can be widely used in solution-processed organic electronic devices.