Browsing by Author "Chiang, Chien-Ming"

Now showing 1 - 2 of 2

Synthesis and Characterization of a Narrow-Bandgap Polymer Containing Alternating Cyclopentadithiophene and Diketo-Pyrrolo-Pyrrole Units for Solar Cell Applications
(2010-04-01)
Chen, Guan-Yu
;
Chiang, Chien-Ming
;
Kekuda, Dhananjay
;
Lan, Shang-Che
;
Chu, Chih-Wei
We have synthesized a narrow-bandgap conjugated polymer (PCTDPP) containing alternating cyclopentadithiophene (CT) and diketo-pyrrolo-pyrrole (DPP) units by Suzuki coupling. This PCTDPP exhibits a low band gap of 1.31 eV and a broad absorption band from 350 to 1000 nm, which allows it to absorb more available photons from sunlight. A bulk hetero-junction polymer solar cell incorporating PCTDPP and C(70) at a blend ratio of 1:3 exhibited a high short-circuit current of 10.87 mA/cm(2) and a power conversion efficiency of 2.27%. (C) 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1669-1675,2010
Synthesis and Characterization of Pyrido[3,4-b]pyrazine-Based Low-Bandgap Copolymers for Bulk Heterojunction Solar Cells
(2010-08-10)
Yuan, Mao-Chuan
;
Chiu, Mao-Yuan
;
Chiang, Chien-Ming
;
Wei, Kung-Hwa
;
材料科學與工程學系
We have used Stille polycondensation to prepare a series of low-bandgap copolymers, P1-P4, by conjugating the electron-accepting pyrido[3,4-b]pyrazine (PP) moieties with the electron-rich benzo[1,2-b:3,4-b']dithiophene (BDT) or cyclopentadithiophene (CPDT) units. P1 and P3 are based on PP and BDT units while P2 and P4 are based on PP and CPDT units. All of these polymers exhibited excellent thermal stability and sufficient energy offsets for efficient charge transfer and dissociation, as determined through thermogravimetric analyses and cyclic voltammetry, respectively. The bandgaps of the polymers could be tuned in the range 1.46-1.60 eV by using the two different donors, which have different electron-donating abilities. The three-component copolymers, P3 and P4, incorporating the thiophene and bithiophene segments, respectively, absorbed broadly, covering the solar spectrum from 350 to 800 nm. The morphologies of the blends of P3 and P4 with [6,6]-phenyl-C(70)-butyric acid methyl ester (PC(70)BM) were more homogeneous than those of P1 and P2; in addition, devices incorporating the P3 and P4 blends exhibited superior performance. The best device performance resulted from an active layer containing the P4:PC(70)BM blend; the short-circuit current was 10.85 mA cm(-2) and the power conversion efficiency was 3.15%.