Browsing by Author "Chen, Cheng-Lun"

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Molecular-weight-dependent nanoscale morphology in silole-containing cyclopentadithiophene polymer and fullerene derivative blends
(2011-11-01)
Huang, Jen-Hsien
;
Chen, Fang-Chung
;
Chen, Cheng-Lun
;
Huang, Annie Tzuyu
;
Hsiao, Yu-Sheng
We have investigated the effect of polymer molecular weight (MW) on the morphology and efficiency of bulk heterojunction (BHJ) solar cells comprised of poly[(4,4'-bis(2-ethyl-hexyl)dithieno[3,2-b: 2',3'-d] silole)-2,6-diyl-alt-(5,5'-thienyl-4,4'-dihexyl-2,2'-bithiazole)2,6- diyl] (Si-PCPDTTBT) and [6,6]-phenyl C(61) butyric acid methyl ester (PCBM). Striking morphological changes are observed in BHJ films upon the change of the polymer MW. Atomic force microscopy and transmission electron microscopy studies suggest that high MW polymer generated high degree of phase separation, leading to formation of an inter-penetrating network for carrier transport. The X-ray diffraction investigation indicated that increased pi-pi stacking in Si-PCPDTTBT with increasing polymer MWs results in an increase in hole mobility of Si-PCPDTTBT and electron mobility of PCBM as well as the red shift absorption spectrum in BHJ films. The solar cells based on PCBM with high-MW Si-PCPDTTBT deliver power conversion efficiencies of 3.33%. (C) 2011 Elsevier B.V. All rights reserved.
Solvent-Annealing-Induced Self-Organization of Poly(3-hexylthiophene), a High-Performance Electrochromic Material
(2009-12-01)
Huang, Jen-Hsien
;
Yang, Chuan-Yi
;
Hsu, Chih-Yu
;
Chen, Cheng-Lun
;
Lin, Lu-Yin
We have systematically studied the self-organization of poly(3-hexylthiophene) (P3HT), an electrochromic material, upon control of the solvent evaporation race. We characterized these polymer films using atomic force microscopy and X-ray diffraction measurements. Well-ordered P3HT structures were developed after solvent annealing; these highly crystalline structures exhibited enhanced electrochromic contrast and reduced resistance within the film, leading to larger coloration efficiencies and faster switching times. The optical contrast (Delta%T), coloration efficiency, and switching time of the P3HT films increased from 54.2%, 182,6 cm(2) C(-1), and 5.3 s, respectively, prior to solvent annealing to 64.8%, 293.5 cm(2) C(-1), and 3.2 s, respectively, after application of the solvent-annealing conditions.
Using a low temperature crystallization process to prepare anatase TiO(2) buffer layers for air-stable inverted polymer solar cells
(2010-01-01)
Huang, Jen-Hsien
;
Wei, Hung-Yu
;
Huang, Kuan-Chieh
;
Chen, Cheng-Lun
;
Wang, Rui-Ren
In this study, we fabricated inverted polymer solar cells featuring titanium dioxide (TiO(2)) as the electron collection layer and vanadium (V) oxide (V(2)O(5)) as the hole collection layer. TiO(2) films (anatase phase) were prepared by combining electrochemical deposition with high-pressure crystallization. The low temperature process used to obtain the TiO(2) films minimized interdiffusion of Ti and In species between the TiO(2) and ITO films and maintained the conductivity of the indium tin oxide substrate. The inverted device reached a power conversion efficiency of 3.22% and exhibited much better stability under ambient conditions relative to that of the corresponding conventional device.
Using a low temperature crystallization process to prepare anatase TiO2 buffer layers for air-stable inverted polymer solar cells
(2010-01-01)
Huang, Jen-Hsien
;
Wei, Hung-Yu
;
Huang, Kuan-Chieh
;
Chen, Cheng-Lun
;
Wang, Rui-Ren
In this study, we fabricated inverted polymer solar cells featuring titanium dioxide (TiO2) as the electron collection layer and vanadium (V) oxide (V2O5) as the hole collection layer. TiO2 films (anatase phase) were prepared by combining electrochemical deposition with high-pressure crystallization. The low temperature process used to obtain the TiO2 films minimized interdiffusion of Ti and In species between the TiO2 and ITO films and maintained the conductivity of the indium tin oxide substrate. The inverted device reached a power conversion efficiency of 3.22% and exhibited much better stability under ambient conditions relative to that of the corresponding conventional device.