Browsing by Author "Huang, Chun-Hao"

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Electro-optical properties of poly(1-(difluorophenyl)-2(4-alkylcyclohexyl phenyl)acetylene) organic light-emitting diodes
(2007-07-16)
Huang, Chun-Hao
;
Lee, Chih-Wen
;
Hsu, Chain-Shu
;
Renaud, Cedric
;
Nguyen, Thien-Phap
For organic light-emitting diodes (OLEDs) applications, we have investigated novel polymers, using substituted polyacetylenes (PA), poly(I (fluorophenyl)-2-(alkylcyclohexylphenyl)acetylene) (PDPA-nF) (n =1 or n = 2) which exhibit air stability, better solubility in common organic solvent and higher luminescence than polyacetylene. In this study, we have used poly[(1-(3,4-difluorophenyl)-2-(4-pentylcyclohexylphenyl) acetylene)] (PDPA-2F) as an emitter in OLEDs and their performance was determined by measuring the cuffent-voltage-luminance characteristic. The devices have a maximum brightness of 827 candela (cd)/M-2 at 12 V and a maximum current efficiency of 0. 7 8 cd/A at 9 V with a maximum luminescence at 536 nm. Influence of the metal electrode on the charge injection was studied using several cathode configurations (Ca, Al and Au) for the devices. Furthermore, the charge injection and transport processes were correlated to the presence of traps inside the polymer, determined by deep level transient spectroscopy (DLTS). (c) 2007 Elsevier B.V. All rights reserved.
Self-assembly monolayer of anatase titanium oxide from solution process on indium tin oxide glass substrate for polymer photovoltaic cells
(2007-06-04)
Huang, Chun-Hao
;
Huang, Chia-Hua
;
Nguyen, Thien-Phap
;
Hsu, Chain-Shu
;
應用化學系
Titanium dioxide (TiO(2)) thin films were deposited on indium tin oxide (ITO) coated glass substrates by a liquid phase deposition method using two different precursor concentrations of 0.01 M and 0.005 M [NH(4)](2)TiF(6). Characterizations of the deposited TiO(2) films were performed by using different spectroscopic techniques including X-ray photoelectron spectroscopy, Raman spectroscopy and X-ray diffraction. From scanning electron microscopy observation, the surface of the TiO(2) films show a ricelike morphology. We have fabricated polymer-based photovoltaic cells (PCs) using the studied TiO(2) films and compared their performances to those using bare ITO-coated glass substrates. The structure of the PCs is glass/ITO/TiO(2)/PCBM:P3HT/Au where PCBM:P3HT is poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester. The power conversion efficiency of these devices is determined to be 0.85%, which is higher than that of similar devices without TiO(2) films (0.13%). (C) 2007 Elsevier B.V. All rights reserved.
Synthesis and Electroluminescent Properties of Disubstituted Polyacetylene Derivatives Containing Multi-Fluorophenyl and Cyclohexylphenyl Side Groups
(2009-01-02)
Yang, Sheng-Hsiung
;
Huang, Chun-Hao
;
Chen, Chiu-Hsiang
;
Hsu, Chain-Shu
;
應用化學系
A new series of disubstituted polyacetylene derivatives that contain multi-fluorine atoms on the pendent phenyl ring have been synthesized and characterized. The results reveal a greater red-shift in UV-vis absorption and PL emission upon incorporating more fluorine atoms on the pendent phenyl ring. Among them, disubstituted polyacetylene with a difluorophenyl group (PDPA-2F) showed the highest luminescent efficiency. The F device performance can be promoted by blending a hole-transporting material TM-TPD into PDPA-2F as the active layer or by using a light-emitting copolymer in which PDPA-2F was copolymerized with a carbazole group (PDPA-2Fcab). A light-emitting diode of ITO/PEDOT/PDPA-2Fcab/Ca/Al revealed a maximum luminescence of 4230 cd . m(-2) at 14 V and a maximum current efficiency of 3.37 cd . A(-1) at 7 V.
Vertical Phase Separation in Poly(3-hexylthiophene): Fullerene Derivative Blends and its Advantage for Inverted Structure Solar Cells
(2009-04-23)
Xu, Zheng
;
Chen, Li-Min
;
Yang, Guanwen
;
Huang, Chun-Hao
;
Hou, Jianhui
A method which enables the investigation of the buried interfaces without altering the properties of the polymer films is used to study vertical phase separation of spin-coated poly(3-hexylthiophene) (P3HT):fullerene derivative blends. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) analysis reveals the P3HT enrichment at the free (air) surfaces and abundance of fullerene derivatives at the organic/substrate interfaces. The vertical phase separation is attributed to the surface energy difference of the components and their interactions with the substrates. This inhomogeneous distribution of the donor and acceptor components significantly affects photovoltaic device performance and makes the inverted device structure a promising choice.