Browsing by Author "Lin, Tai-Yen"

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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.
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
;
Cheng, Yen-Ju
;
Lin, Tai-Yen
;
Chang, Chih-Yu
;
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.
Dithienocyclopentathieno[3,2-b]thiophene Hexacyclic Arene for Solution-Processed Organic Field-Effect Transistors and Photovoltaic Applications
(2012-04-01)
Cheng, Yen-Ju
;
Chen, Chiu-Hsiang
;
Lin, Tai-Yen
;
Hsu, Chain-Shu
;
應用化學系
We have developed a ladder-type dithienocyclopentathieno[3,2-b]thiophene (DTCTT) hexacyclic unit in which the central thieno[3,2-b]thiophene ring was covalently fastened to two adjacent thiophene rings through carbon bridges, thereby forming two connected cyclopentadithiophene (CPDT) units in a hexacyclic coplanar structure. This stannylated Sn-DTCTT building block was copolymerized with three electron-deficient acceptors, dibromo-thieno[3,4-c]pyrrole-4,6-dione (TPD), dibromo-benzothiadiazole (BT), and dibromo-phenanthrenequinoxaline (PQX), by Stille polymerization, thereby furnishing a new class of alternating donoracceptor copolymers: PDTCTTTPD, PDTCTTBT, and PDTCTTPQX, respectively. Field-effect transistors based on PDTCTTPQX and PDTCTTBT yielded high hole mobilities of 0.017 and 0.053 cm2?V-1?s-1, respectively, which are among the highest performances among amorphous donoracceptor copolymers. A bulk heterojunction solar cell that incorporated PDTCTTTPD with the lower-lying HOMO energy level delivered a higher Voc value of 0.72 V and a power conversion efficiency (PCE) value of 2.59?%.
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
;
Wu, Kuan-Yi
;
Lin, Tai-Yen
;
Wu, Jhong-Sian
;
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.