Browsing by Author "Chen, Yung-Lung"

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A new ladder-type benzodi(cyclopentadithiophene)-based donor-acceptor polymer and a modified hole-collecting PEDOT: PSS layer to achieve tandem solar cells with an open-circuit voltage of 1.62 V
(2013)
Chen, Yung-Lung
;
Kao, Wei-Shun
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Tsai, Che-En
;
Lai, Yu-Ying
;
Cheng, Yen-Ju
We have developed a new ladder-type conjugated polymer PBDCPDT-FBT and a robust interconnecting layer (ICL) integrating a hole-collecting m-PEDOT:PSS layer with an electron-collecting ZnO layer. The inverted device using PBDCPDT-FBT exhibited a high power conversion efficiency (PCE) of 5.76% with a V-oc of 0.81 V, a J(sc) of 12.82 mA cm(-2), and a FF of 55.5%. The inverted tandem device incorporating the PBDCPDT-FBT and ICL achieves a V-oc of 1.62 V leading to a PCE of 7.08%.
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
;
Liang, Wei-Wei
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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).
Self-assembled tri-, tetra- and penta-ethylene glycols as easy, expedited and universal interfacial cathode-modifiers for inverted polymer solar cells
(2016-06-14)
Cao, Fong-Yi
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Lai, Yu-Ying
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Chen, Yung-Lung
;
Cheng, Yen-Ju
;
應用化學系
Non-conjugated triethylene glycol (3-EG), tetraethylene glycol (4-EG) and pentaethylene glycol (5-EG) are presented as new cathode modification materials to achieve high-performance inverted-PCSs. By spin-coating from a non-chlorinated solvent, these small molecules can self-assemble on ITO via surface coordination and hydrogen bonding to form an ultra-thin layer. Theoretical simulations reveal that the coordination of oxygen atoms in the EG molecules to indium moieties on the ITO surface is the major mechanism in inducing interfacial dipoles, thereby reducing the work function (W-F) of ITO for efficient electron collection. Based on the PBDTTT-EFT:PC71BM blend, the bulk heterojunction device using the 5-EG layer exhibited a higher short-circuit current density (J(sc)) of 15.27 mA cm(-2), fill factor (FF) of 0.69, and power conversion efficiency (PCE) of 8.46%, which are better than those of the corresponding devices using either inorganic ZnO or non-conjugated poly(ethylene oxide) (PEO) as the cathode buffer layer. More importantly, this simple and expedited strategy is also demonstrated to be universally applicable to various p-type conjugated polymers. The EG oligomers with well-defined chemical structures have the advantages of easy availability, simple processability and good device reproducibility, which are crucial keys for future commercialization using large-scale roll-to-roll production.
Synthesis and Isomeric Effects of Ladder-Type Alkylated Terbenzodithiophene Derivatives
(2016-03-18)
Chen, Yung-Lung
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Hsu, Jhih-Yang
;
Lin, Fang-Yu
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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 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 of a New Ladder-Type Benzodi(cyclopentadithiophene) Arene with Forced Planarization Leading to an Enhanced Efficiency of Organic Photovoltaics
(2012-10-23)
Chen, Yung-Lung
;
Chang, Chih-Yu
;
Cheng, Yen-Ju
;
Hsu, Chain-Shu
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應用化學系
We have developed a new heptacyclic benzodi(cyclopentadithiophene) (BDCPDT) unit, where 3,7-positions of the central benzo[1,2-b:4,5-b']dithiophenes (BDT) subunit are covalently rigidified with 3-positons of the two external thiophenes by two carbon bridges, forming two external CPDT rings that share two thiophene rings with the central BDT core. The distannyl-BDCPDT building block was copolymerized with 1,3-dibromo-thieno[3,4-c]pyrrole-4,6-dione (TPD) by Stille polymerization to afford a new alternating donor-acceptor copolymer PBDCPDT-TPD. The implementation of forced planarization greatly suppresses the interannular twisting to extend the effective conjugated length and preserve the interactions between the donor and acceptor segments. The device using the PBDCPDT-TPD/PC71BM (1:3 in wt%) blend processed with dimethyl sulfoxide as an additive delivered a marked PCE of 6.6% which represents a significant enhancement compared to the device using the corresponding nonfused polymer analogue with a PCE of 0.2%.
Synthesis of Two-Dimensional Terbenzodithiophene-based Derivative by Palladium-catalyzed C-H Benzannulation and Its Donor-Acceptor Copolymers for Organic Photovoltaics
(2018-01-01)
Cao, Fong-Yi
;
Chen, Yung-Lung
;
Lai, Yu-Ying
;
Cheng, Yen-Ju
;
應用化學系
A new two-dimensional tetrathienyl-TBDT (TBDT-4T) was synthesized by employing palladium-catalyzed C-H benzannulation between an iodobiaryl and 1,2-dithienylacetylene. The stannylated TBDT-4T was copolymerized with di(thiophenyl)difluorobenzothiadiazole (FBT) and fluorothienothiophene (FTT) monomers to yield PTBDT-FBT and PTBDT-FTT, which showed high decomposition temperatures (421 and 408 degrees C) and deep-lying HOMO levels (-5.80 and -5.84 eV). The inverted solar cell device using PTBDT-FBT:PC71BM (1: 1 in wt%) blend showed a power conversion efficiency (PCE) of 4.16%, while the device using PTBDT-FTT:PC71BM (1: 2 in wt%) blend showed a PCE of 3.98%.
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
;
Liao, Ming-Hung
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Chen, Yung-Lung
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Cheng, Sheng-Wen
;
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.