MEHPPV元件中之電荷傳導異向性
The Charge Transport Anisotropy in MEHPPV (poly(2-methoxy-5-(2’-ethylhexykoxy)-1,4-phenylene vinylene) Devices
Date Issued
2007
Date
2007
Author(s)
Chang, Zhan-Wei
DOI
en-US
Abstract
The hole mobility in vertical and horizontal directions were measured by means of time-resolved or transient electroluminescence (TrEL) and field-effect transistor (FET) methods for poly(2-methoxy-5-(2’-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV). The optical properties and morphology were studied for understanding the optical and morphological effects on charge transport properties. MEH-PPV films prepared from chlorobenzene (CB) and toluene (TL) were used and fabricated into devices in this work. The results indicted the optical properties are identical but different in hole mobility. In addition, the charge mobility shows obvious difference in vertical and horizontal direction. Further, the morphological effect in conjugated polymer films was induced by using different solvents. Through scattering measurements, the solvent induced layered structure within polymer films spun from chlorobenzene (CB) solution is more predominant, however, the films spun from toluene (TL) solution show weak layered feature. Comparing morphological effects with the hole transporting results measured by thin film transistor device (horizontal direction) and polymer light emitting diode (PLED) based time resolved electroluminescence method (vertical direction), charge transport anisotropy was observed as a result of the layered structure in the conjugated polymer. Amazingly, this structural anisotropy corresponds with the mobility anisotropy and it is believed to be consistent with hole carriers owning greater mobility in the regions of high electron density which is parallel to the substrate.
Subjects
MEHPPV
載子遷移率
型態
光學性質
X光反射
場效應電晶體
時間暫態電激發光。
MEH-PPV
Mobility
Morphology
Optical properties
X-ray reflectivity
FET
TrEL
Type
thesis
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