Browsing by Author "Meng, H. F."

Now showing 1 - 4 of 4

Electron transport and electroluminescent efficiency of conjugated polymers
(2009-01-01)
Tseng, S. R.
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Chen, Y. S.
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Meng, H. F.
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Lai, H. C.
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Yeh, C. H.
The relation between charge balance and electroluminescent efficiency for polymers is studied systematically in this work. Light-emitting diodes of several kinds of polymers with very different efficiency are compared. The electron and hole currents are measured in the uni-polar devices and fitted by the theoretical model to get carrier mobilities. The universal features of the high efficiency polymers are that the electron and hole mobilities are comparable and the electron current is larger than the hole current due to the higher hole barriers. The electron current is more crucial than hole current to determine the efficiency in the bipolar light-emitting diode. The purity of polymers and low electron injection barriers both play significant roles in producing stronger electron currents. These results give the physical rules for designing new polymers and the device structures to achieve highly electroluminescent devices. Crown Copyright (C) 2008 Published by Elsevier B.V. All rights reserved.
Hybrid White Light-emitting Diodes by Organic-Inorganic materials
(2015)
Chen, K. J.
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Lai, Y. C.
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Lin, B. C.
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Lin, C. C.
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Chiu, S. H.
This study demonstrated the high uniformity hybrid white light-emitting didoes with polyfluoren (PFO) polymer and quantum dot (QD) with different CCT range from 3000K to 9000K.
Performance Optimization of Organic Solar Cells
(2014-08-01)
Wong, Y. Q.
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Wong, H. Y.
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Tan, C. S.
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Meng, H. F.
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物理研究所
Organic solar cells (OSCs) have been gaining great popularity in recent years due to their potentials to be low cost, lightweight, and flexible. The performance of OSCs is growing steadily, and they have achieved a power conversion efficiency close to 10% (for single-junction polymer-fullerene OSC). Although there are still limitations and challenges faced by the development of OSCs, in view of the potentials, recent studies have been focusing on the design optimization of OSC layer structure through material engineering, interfacial layer insertion, layer thickness optimization, and morphological control. In this paper, we provide a comprehensive review and detailed discussion on the optimization works and development on OSCs, with particular focus on the bulk-heterojunction (BHJ) polymer-fullerene OSCs. We also provide a summary of the performance, in a chronological order, and the future outlook of OSC.
Triplet exciton energy transfer in polyfluorene doped with heavy metal complexes studied using photoluminescence and photoinduced absorption
(2006-12-01)
Liao, H. H.
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Meng, H. F.
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Horng, S. F.
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Lee, W. S.
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Yang, J. M.
Modulated photoinduced absorption and photoluminescence are used to study triplet-to-triplet Dexter energy transfer in Ir-complexes/polyfluorene blend systems. There is no Dexter energy transfer for red iridium (III)bis[2-(9,9-dibutylfluorenyl)-1-isoquinoline(acetylacetonate)] (DFIr) and red iridium (III) bis([2-(2-benzo-thienyl)pyridinatoN,C3] acetyl-acetonate) (BtpIr) dopants. Although green iridium(III)tris[2-(4-tolyl)pyridinato-N,C2] [Ir(mppy)(3)] has no triplet confinement in polyfluorene host, it has clear evidence for Dexter energy transfer. Aggregation and dopant lifetime are shown to significantly affect the energy transfer. The presence of Dexter transfer implies the possibility to harvest triplet excitons of polyfluorene in polymer light-emitting diodes even without carrier trapping and triplet exciton confinement.