Browsing by Author "Wu, Jhong-Sian"

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A New sp2-sp2 Dialkylethylene-Bridged Heptacyclic Ladder-Type Arene for High Efficiency Polymer Solar Cells
(2013-04-01)
Wu, Jhong-Sian
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Lai, Yu-Ying
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Cheng, Yen-Ju
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Chang, Chih-Yu
;
Wang, Chien-Lung
A new dithienobenzo-carbazole (DTBC) heptacyclic arene using sp2-sp2 dialkylethylene moiety as the bridge was successfully synthesized by Suzuki-Miyaura cross-coupling reaction. This facile benzoannulation planarizes the conjugated framework with the concomitant introduction of four octyl substituents, making the newly designed copolymer PDTBCDTBT exhibit solution processability, superior absorption ability, lower-lying HOMO energy level, and crystalline nature. The solar cell using PDTBCDTBT has produced a high efficiency of 6.2%, which outperforms the corresponding sp3-hybridized C-bridged, Si-bridged and N-bridged analogous 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
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Wu, Jhong-Sian
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Lin, Tai-Yen
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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.
Carbazole-based heptacyclic arenes with carbon, silicon, and nitrogen bridges: Synthesis, molecular properties and photovoltaic applications
(2012-03-25)
Wu, Jhong-Sian
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Cheng, Yen-Ju
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Hsu, Chain-Shu
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應用化學系
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Department of Applied Chemistry
Carbazole-Based Ladder-Type Heptacylic Arene with Aliphatic Side Chains Leading to Enhanced Efficiency of Organic Photovoltaics
(2011-05-10)
Cheng, Yen-Ju
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Wu, Jhong-Sian
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Shih, Ping-I
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Chang, Chih-Yu
;
Jwo, Pei-Chi
By utilizing Friedel-Crafts cyclization, we have successfully designed and synthesized a ladder-type heptacyclic carbazole-dicyclopentathiophene (CDCT-C8) unit in which two outer thiophene subunits are covalently fastened to the central 2,7-carbazole core. The nitrogen-directing effect of the carbazole unit facilitates the intrarnolecular cydization and thereby suppresses the acid-induced dehydration, allowing us to incorporate two octyl side chains on the cyclopentadiene rings in good chemical yield. The distannyl-CDCT-C8 building block was copolymerized with benzothiadiazole (BT), dithienylbenzothiadiazole (DTBT), dithienyldiketopyrrolopyrrole (DTDPP) and quinoxaline (QX) units by Stile polymerization to afford four alternating donor acceptor copolymers, PCDCTBT-C8, PCDCTDTBT-C8, PCDCTDTDPP-C8 and PCDCTQX-C8, respectively. The device based on the PCDCTBT-C8:PG7IBM (1:3 in wt%) blend exhibited a V(oc) of 0.74 V, a J(sc) of 10.3 mA/cm(2), a FF of 60%, delivering an impressive PCE of 4.6%. This value represents one of the best performances among carbazole-based conjugated polymers in the literatures. The corresponding PCDCTBT-C8 :PC(71)BM blend showed a high hole mobility of 1.2 x 10(-3) cm(2) V(-1) s(-1), which is in good agreement with its high current density and fill factor. This improved performance is associated with the modification of the aliphatic side chains on the CDCT structure to optimize the interchain interactions for enhanced charge transporting. The devices based on PCDCTDTBT-C8, PCDCTDTDPP-C8 and PCDCTQX-C8 polymers also displayed promising efficiencies of 3.5%, 2.4%, and 1.8%, respectively.
Combination of Molecular, Morphological, and Interfacial Engineering to Achieve Highly Efficient and Stable Plastic Solar Cells
(2012-01-24)
Chang, Chih-Yu
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Cheng, Yen-Ju
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Hung, Shih-Hsiu
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Wu, Jhong-Sian
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Kao, Wei-Shun
A flexible solar device showing exceptional air and mechanical stability is produced by simultaneously optimizing molecular structure, active layer morphology, and interface characteristics. The PFDCTBT-C8-based (see figure) devices with inverted architecture exhibited excellent power conversion efficiencies of 7.0% and 6.0% on glass and flexible substrates, respectively.
Dithienocarbazole-Based Ladder-Type Heptacyclic Arenes with Silicon, Carbon, and Nitrogen Bridges: Synthesis, Molecular Properties, Field-Effect Transistors, and Photovoltaic Applications
(2012-04-24)
Wu, Jhong-Sian
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Cheng, Yen-Ju
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Lin, Tai-Yen
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Chang, Chih-Yu
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Shih, Peng-I.
A new class of ladder-type dithienosilolo-carbazole (DTSC), dithienopyrrolo-carbazole (DTPC), and dithienocyclopenta-carbazole (DTCC) units is developed in which two outer thiophene subunits are covalently fastened to the central 2,7-carbazole cores by silicon, nitrogen, and carbon bridges, respectively. The heptacyclic multifused monomers are polymerized with the benzothiadiazole (BT) acceptor by palladium-catalyzed cross-coupling to afford three alternating donor-acceptor copolymers poly(dithienosilolo-carbazole-alt-benzothiadiazole) (PDTSCBT), poly(dithienocyclopenta-carbazole-alt-benzothiadiazole) (PDTCCBT), and poly(dithienopyrrolo-carbazole-alt-benzothiadiazole) (PDTPCBT). The silole units in DTSC possess electron-accepting ability that lowers the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PDTSCBT, whereas stronger electron-donating ability of the pyrrole moiety in DTPC increases the HOMO and LUMO energy levels of PDTPCBT. The optical bandgaps (Egopt) deduced from the absorption edges of thin film spectra are in the following order: PDTSCBT (1.83 eV) > PDTCCBT (1.64 eV) > PDTPCBT (1.50 eV). This result indicated that the donor strength of the heptacyclic arenes is in the order: DTPC > DTCC > DTSC. The devices based on PDTSCBT and PDTCCBT exhibited high hole mobilities of 0.073 and 0.110 cm2 V-1 s-1, respectively, which are among the highest performance from the OFET devices based on the amorphous donor-acceptor copolymers. The bulk heterojunction photovoltaic device using PDTSCBT as the p-type material delivered a promising efficiency of 5.2% with an enhanced open circuit voltage, Voc, of 0.82 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
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Cheng, Yen-Ju
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Hsu, Chain-Shu
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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.
Donor-acceptor polymers based on multi-fused heptacyclic structures: synthesis, characterization and photovoltaic applications
(2010)
Wu, Jhong-Sian
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Cheng, Yen-Ju
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Dubosc, Martin
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Hsieh, Chao-Hsiang
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Chang, Chin-Yen
We report here two novel 2,7-fluorene- and 2,7-carbazole-based conjugated polymers PFDCTBT and PCDCTBT containing ladder-type heptacyclic structures with forced planarity. PCDTBT shows excellent solubility, low band gap and high hole mobility, leading to a power conversion efficiency of 3.7%.
Influences of the Non-Covalent Interaction Strength on Reaching High Solid-State Order and Device Performance of a Low Bandgap Polymer with Axisymmetrical Structural Units
(2013-05-07)
Jheng, Jyun-Fong
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Lai, Yu-Ying
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Wu, Jhong-Sian
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Chao, Yi-Hsiang
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Wang, Chien-Lung
A high organic field-effect transistor mobility (0.29 cm(2)V(-1)s(-1)) and bulk-heterojunction polymer solar cell performance (PCE of 6.82%) have been achieved in a low bandgap alternating copolymer consisting of axisymmetrical structural units, 5,6-difluorobenzo-2,1,3-thiadiazole. Introducing the fluorine substituents enhanced intermolecular interaction and improved the solid-state order, which consequently resulted in the highest device performances among the 2,1,3-thiadiazole-quarterthiophene based alternating copolymers.
Interface Engineering to Enhance the Efficiency of Conventional Polymer Solar Cells by Alcohol-/Water-Soluble C-60 Materials Doped with Alkali Carbonates
(2013-06-12)
Lai, Yu-Ying
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Shih, Ping-I
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Li, Yi-Peng
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Tsai, Che-En
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Wu, Jhong-Sian
Two new C-60-based n-type materials, EGMC-OH and EGMC-COOH, functionalized with hydrophilic triethylene glycol groups (TEGs), have been synthesized and employed in conventional polymer solar cells. With the assistance of the TEG-based surfactant, EGMC-OH and EGMC COOH can be dissolved in highly polar solvents to implement the polar/nonpolar orthogonal solvent strategy, forming an electron modification layer (EML) without eroding the basis of ITO/PEDOT:PSS/P3HT:PC61M/EML/Ca/Al configuration with the insertion of the EGMC OH and EGMC COOH EML between the active layer and the electrode have thus been successfully realized by cost-effective solution processing techniques. Moreover, the electron conductivity of the EML can be improved by incorporating alkali carbonates into the EGMC-COOH EML. Compared to the pristine device with a PCE of 3.61%, the devices modified by the Li2CO3-doped EGMC-COOH EML achieved a highest PCE of 4.29%. Furthermore, we demonstrated that the formation of the EGMC-COOH EML can be utilized as a general approach in the fabrication of highly efficient multilayer conventional devices. With the incorporation of the EGMC-COOH doped with 40 wt % Li2CO3, the PCDCTBT-C8:PC17BM-based device exhibited a superior PCE of 4.51%, which outperformed the corresponding nonmodified device with a PCE of 3.63%.
Morphological Stabilization by Supramolecular Perfl uorophenyl-C-60 Interactions Leading to Effi cient and Thermally Stable Organic Photovoltaics
(2014-03-01)
Liao, Ming-Hung
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Tsai, Che-En
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Lai, Yu-Ying
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Cao, Fong-Yi
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Wu, Jhong-Sian
A new PC61BM-based fullerene, [6,6]-phenyl-C-61 butyric acid pentafluorophenyl ester (PC61BPF) is designed and synthesized. This new n-type material can replace PC61BM to form a P3HT:PC61BPF binary blend or serve as an additive to form a P3HT:PC61BM:PC61BPF ternary blend. Supramolecular attraction between the pentafluorophenyl group of PC61BPF and the C-60 cores of PC61BPF/PC61BM can effectively suppress the PC61BPF/PC61BM materials from severe aggregation. By doping only 8.3 wt% PC61BPF, device PC(61)BP(F)651 exhibits a PCE of 3.88% and decreases slightly to 3.68% after heating for 25 h, preserving 95% of its original value. When PC61BP with non-fluorinated phenyl group is used to substitute PC61BPF, the stabilizing ability disappears completely. The efficiencies of PC(61)BP651 and PC(61)BP321 devices significantly decay to 0.44% and 0.11%, respectively, after 25 h isothermal heating. Most significantly, this strategy is demonstrated to be effective for a blend system incorporating a low band-gap polymer. By adding only 10 wt% PC61BPF, the PDTBCDTB:PC71BM-based device exhibits thermally stable morphology and device characteristics. These findings demonstrate that smart utilization of supramolecular interactions is an effective and practical strategy to control morphological evolution.
New Angular-Shaped and Isomerically Pure Anthradithiophene with Lateral Aliphatic Side Chains for Conjugated Polymers: Synthesis, Characterization, and Implications for Solution-Prossessed Organic Field-Effect Transistors and Photovoltaics
(2012-06-26)
Wu, Jhong-Sian
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Lin, Chung-Te
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Wang, Chien-Lung
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Cheng, Yen-Ju
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Hsu, Chain-Shu
An isomerically pure anti-anthradithiophene (aADT) arranged in an angular shape is developed. Formation of the framework of aADT incorporating four lateral alkyl substituents was accomplished by a one-pot benzannulation via multiple Suzuki coupling. This newly designed 2,8-stannylated aADT monomer was copolymerized with a ditheniodiketopyrrolopyrrole (DPP) unit and a bithiophene unit, respectively, to furnish an alternating donor-acceptor copolymer poly(anthradithiophene-alt-dithienyldiketopyrrolopyrrole) (PaADTDPP) and a thiophene-rich poly(anthradithiophene-alt-bithiophene) (PaADTT). PaADTT with crystalline nature achieved a high FET mobility of 7.9 x 10(-2) cm(-2) V-1 s(-1) with an on-off ratio of 1.1 x 10(7). The photovoltaic device based on the PaADTDPP:PC71BM (1:2.5, w/w) blend exhibited a V-oc, of 0.66 V, a J(sc) of 9.49 mA/cm(2), and a FF of 58.4%, delivering a power conversion efficiency (PCE) of 3.66%. By adding 1.5 vol % 1-chloronaphthalene (CN) as a processing additive, the PCE can be improved to 4.24%. We demonstrated that these angular-shaped and alkylated aADT-based polymers have better organic photovoltaic (OPVs) and field-effect transistor (FETs) characteristics than the linear-shaped ADT-containing polymers.
Porphyrin-Incorporated 2D D-A Polymers with Over 8.5% Polymer Solar Cell Efficiency
(2014-08-13)
Chao, YI-Hsiang
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Jheng, Jyun-Fong
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Wu, Jhong-Sian
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Wu, Kuan-Yi
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Peng, Hsih-Hao
Porphyrin-Incorporated 2D D-A Polymers with Over 8.5% Polymer Solar Cell Efficiency
(2014-08-13)
Chao, YI-Hsiang
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Jheng, Jyun-Fong
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Wu, Jhong-Sian
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Wu, Kuan-Yi
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Peng, Hsih-Hao
Recent Advances in P-Type Conjugated Polymers for High-Performance Solar Cells
(2015)
Cheng, Yen-Ju
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Wang, Chien-Lung
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Wu, Jhong-Sian
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Hsu, Chain-Shu
;
應用化學系
Bulk-heterojunction (BHJ) polymer solar cells have achieved significant progress in the recent years, with the efficiency now over 10 %. The p-type polymer in the BHJ blend played a key role in the amazing technology advance. In this chapter, we will timely update over 80 conjugated polymers leading to high-performance solar cells. The principle of molecular design with structure-properties relationship with respect to device characteristics will also be discussed, as the materials and morphology are tightly interconnected.
Role of the Comonomeric Units in Reaching Linear Backbone, High Solid-State Order and Charge Mobilities in Heptacyclic Arene-Based Alternating Copolymers
(2013-10-08)
Lee, Tien-Hsin
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Wu, Kuan-Yi
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Lin, Tai-Yen
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Wu, Jhong-Sian
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Wang, Chien-Lung
Unpredictable trends of charge mobility (mu) in multicyclic heteroarenes-contained polymers remain an obstacle in designing high performance polymers used in polymeric field effect transistors (PFETs). The roles of the comonomeric units in reaching high hole mobility (mu(h)) of copolymers containing a heptacyclic arene unit, dithienocyclopentacarbazole (DTCC) were investigated in this study. A series of four DTCC-based alternating copolymers, PDTCC-1T, PDTCC-3T, PDTCC-BDT, and PDTCC-TT, were synthesized from the Pd-catalyzed copolymerizations between DTCC and comonomeric units including thioene (1T), terthiophene (3T), benzodithiophene (BDT) and thienothiophene (TT) units. Among the four DTCC-based alternating copolymers, highest mobility of 1.36 X 10(-2) cm(2) s(-1) was reached in PDTCC-3T. Optoelectronic and 2D-WAXD studies revealed that strong electronic interaction and highly ordered solid-state structure were only observed in PDTCC-3T. It is attributed to the combination of two axisymmertric units, DTCC and 3T, linearized the polymer backbone, leading to a compact solid-state packing and high mu(h), while centrosymmertic comonomeric units, BDT and TT curved the polymer backbones of PDTCC-BDT and PDTCC-TT, which decreases solid-state order and mu(h). Furthermore, the short axisymmeritric 1T although results in a linear backbone of PDTCC-1T, comparing to 3T, it is too short to effectively reduce interchain steric hindrance caused by the solubilizing octyl chains on DTCC. Thus, effective pi-pi stacking is hindered in PDTCC-1T, resulting in low mu(h). The macroscopic performances of mu(h)s agreed well with the optoelectronic and 2D-WAXD studies. It is concluded that the linear backbone of DTCC copolymers is the prerequisite to reach ordered solid-state packing, which facilitate effective charge transport, and it depends on the prudent choose on the symmetry of the comonomeric unit. In addition, balance between the solubility and adequate crowdedness of lateral side chains is essential for a PFET material to be not only easily processed, but also effectively pi-pi stack.
Solution-Processed (Graphene Oxide)-(d(0) Transition Metal Oxide) Composite Anodic Buffer Layers toward High-Performance and Durable Inverted Polymer Solar Cells
(2013-10-01)
Chao, Yi-Hsiang
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Wu, Jhong-Sian
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Wu, Chen-En
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Jheng, Jyun-Fong
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Wang, Chien-Lung
Synthesis and morphological studies of a poly(5,6-difluorobenzo-2,1,3-thiadiazole-4,7-diyl-alt-quaterchalcogenophene) copolymer with 7.3% polymer solar cell efficiency
(2014-11-21)
Wu, Jhong-Sian
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Jheng, Jyun-Fong
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Chang, Jen-Yun
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Lai, Yu-Ying
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Wu, Kuan-Yi
To obtain a poly(5,6-difluorobenzo-2,1,3-thiadiazole-4,7-diyl-alt-quaterchalcogenophene) (P(FBT-alt-CP4)) copolymer with a small optical band gap (E-g), and to achieve high short-circuit current (J(sc)) in the P(FBT-alt-CP4) : PC71BM polymer solar cells (PSCs), P(FBT-alt-Se2Th2), which contains selenophene-2,5-diyl (-Se-) pi-bridges, was synthesized. P(FBT-alt-Se2Th2) shows a Eg of 1.56 eV and is strongly aggregated in solution. Wide angle X-ray diffraction (WAXD) and grazing incidence X-ray diffraction (GI-XRD) results revealed the high solid-state order of P(FBT-alt-Se2Th2) and its edge-on orientation on the substrate. It delivered a high hole mobility (mu(h)) of 0.36 cm(2) V-1 s(-1) in organic field-effect transistors (OFETs). The strong aggregation tendency of P(FBT-alt-Se2Th2) caused large segregation domains in the P(FBT-alt-Se2Th2) : PC71BM thin film, as is seen in the high-resolution transmission electron microscopy (HR-TEM) images. The addition of 8 vol% of 1-chloronaphthalene (1-CN) effectively suppressed the aggregation and led to more homogeneous active layer morphology. The improved morphology enhanced the J(sc) of the PSCs. A superior PCE of 7.34% with a V-oc of 0.70 V, a J(sc) of 15.8 mA cm(-2), and a FF of 66.4% was achieved in the inverted P(FBT-alt-Se2Th2) : PC71BM PSCs. The strong aggregation of P(FBT-alt-Se2Th2) is likely related to its more straight conjugated backbone according to the theoretical calculation results of the FBT-alt-Se2Th2 repeat unit.