Browsing by Author "Ho, Yu-Ju"

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Synthesis, Photophysical and Photovoltaic Properties of Conjugated Polymers Containing Fused Donor-Acceptor Dithienopyrrolobenzothiadiazole and Dithienopyrroloquinoxaline Arenes
(2012-03-27)
Cheng, Yen-Ju
;
Ho, Yu-Ju
;
Chen, Chiu-Hsiang
;
Kao, Wei-Shun
;
Wu, Cheng-En
We have developed two nitrogen-bridged pentacyclic donor-acceptor dithienopyrrolobenzothiadiazole (DTPBT) and dithienopyrroloquinoxaline (DTPQX) arenes where the two outer electron-rich thiophene moieties are covalently fastened with the central electron-deficient benzothiadiazole and quinoxaline cores by two nitrogen bridges. These rigid and coplanar DTPBT and DTPQX building blocks were copolymerized with fluorene (F), carbazole (C) and cyclopentadithiophene (CPDT) units via Suzuki or Stifle coupling polymerization to afford six new alternating copolymers PFDTPBT, PCDTPBT, PCPDTDTPBT, PFDTPQX, PCDTPQX and PCPDTDTPQX, respectively. The nitrogen bridges not only planarize the structure to induce stronger intermolecular pi-pi interaction but also play an important role in determining the electronic and photophysical properties of the polymers. The device based on PFDTPQX/PC71BM (1:4, w/w) exhibited a open-circuit voltage (V-oc) of 0.72 V, a short-circuit current (J(sc)) of 8.62 mA/cm(2) and a FF of 0.55 leading to a decent power conversion efficiency (PCE) of 3.40% due to the lower-lying HOMO energy level, and the highest hole-mobility of PFDTPQX
Thieno[3,2-b]pyrrolo Donor Fused with Benzothiadiazolo, Benzoselenadiazolo and Quinoxalino Acceptors: Synthesis, Characterization, and Molecular Properties
(2011-10-21)
Cheng, Yen-Ju
;
Chen, Chiu-Hsiang
;
Ho, Yu-Ju
;
Chang, Shu-Wei
;
Witek, Henryk A.
Nitrogen-bridged donor acceptor multifused dithienopyrrolobenzothladiazole (DTPBT) and dibenzothiadiazolopyrrolothlophene (DBTPT) were successfully synthesized by intramolecular Cadogan annulation. The electron-deficient benzothiadiazole unit In DTPBT can be converted to benzoselenadiazole and quinoxaline moieties through reduction/cyclization to generate dithienopyrrolobenzoselenadiazole (DTPBSe) and dithienopyrroloquinoxaline (DTPQX), respectively. The nitrogen atoms function as the bridges for covalent planarization to induce intermolecular interaction and intramolecular charge transfer.