Abstract
The morphology evolution of poly(p-phenylenevinylene)/methanofullerene (MDMO-PPV/ PCBM) composite films as used for photovoltaic devices has been investigated upon thermal annealing under various spatial confinements. Three types of spatial confinement have been studied: no confinement, which corresponds to free-standing composite films; single-sided confinement, in which the composite films are deposited on a substrate; and double-sided or sandwich-like confinement, in which the deposited composite films are additionally covered by a top layer. For all the confinement types, annealing above the glass transition temperature Tg of bulk MDMO-PPV forces crystallization of PCBM molecules into single crystals from the MDMO-PPV matrix and causes phase separation. The mobility of PCBM molecules in the MDMO-PPV matrix and its crystal growth rates decrease with increased degree of confinement. In the case of free-standing films the diffusion rate of PCBM is so high that the molecule incorporation rate at the growing front of the PCBM crystals determines their growth rate; elongated single crystals are formed due to the anisotropy of the crystal growth in the lateral dimensions. For single- and double-sided confinement, the mobility of PCBM is lower, and in particular for double-sided confinement, diffusion instead of incorporation rate of PCBM molecules dominates crystal growth, which results in less elongated (single-sided confinement) and even circular (double-sided confinement) shapes of the single crystals formed. Therefore, spatial confinement reduces the mobility of PCBM molecules and thus its crystallization kinetics in its thin composite films.
| Original language | English |
|---|---|
| Pages (from-to) | 4289-4295 |
| Number of pages | 7 |
| Journal | Macromolecules |
| Volume | 38 |
| Issue number | 10 |
| DOIs | |
| Publication status | Published - May 17 2005 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Materials Chemistry
Cite this
Effect of spatial confinement on the morphology evolution of thin poly(p-phenylenevinylene)/methanofullerene composite films. / Yang, Xiaoniu; Alexeev, Alexander; Michels, Matthias A J; Loos, Joachim.
In: Macromolecules, Vol. 38, No. 10, 17.05.2005, p. 4289-4295.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Effect of spatial confinement on the morphology evolution of thin poly(p-phenylenevinylene)/methanofullerene composite films
AU - Yang, Xiaoniu
AU - Alexeev, Alexander
AU - Michels, Matthias A J
AU - Loos, Joachim
PY - 2005/5/17
Y1 - 2005/5/17
N2 - The morphology evolution of poly(p-phenylenevinylene)/methanofullerene (MDMO-PPV/ PCBM) composite films as used for photovoltaic devices has been investigated upon thermal annealing under various spatial confinements. Three types of spatial confinement have been studied: no confinement, which corresponds to free-standing composite films; single-sided confinement, in which the composite films are deposited on a substrate; and double-sided or sandwich-like confinement, in which the deposited composite films are additionally covered by a top layer. For all the confinement types, annealing above the glass transition temperature Tg of bulk MDMO-PPV forces crystallization of PCBM molecules into single crystals from the MDMO-PPV matrix and causes phase separation. The mobility of PCBM molecules in the MDMO-PPV matrix and its crystal growth rates decrease with increased degree of confinement. In the case of free-standing films the diffusion rate of PCBM is so high that the molecule incorporation rate at the growing front of the PCBM crystals determines their growth rate; elongated single crystals are formed due to the anisotropy of the crystal growth in the lateral dimensions. For single- and double-sided confinement, the mobility of PCBM is lower, and in particular for double-sided confinement, diffusion instead of incorporation rate of PCBM molecules dominates crystal growth, which results in less elongated (single-sided confinement) and even circular (double-sided confinement) shapes of the single crystals formed. Therefore, spatial confinement reduces the mobility of PCBM molecules and thus its crystallization kinetics in its thin composite films.
AB - The morphology evolution of poly(p-phenylenevinylene)/methanofullerene (MDMO-PPV/ PCBM) composite films as used for photovoltaic devices has been investigated upon thermal annealing under various spatial confinements. Three types of spatial confinement have been studied: no confinement, which corresponds to free-standing composite films; single-sided confinement, in which the composite films are deposited on a substrate; and double-sided or sandwich-like confinement, in which the deposited composite films are additionally covered by a top layer. For all the confinement types, annealing above the glass transition temperature Tg of bulk MDMO-PPV forces crystallization of PCBM molecules into single crystals from the MDMO-PPV matrix and causes phase separation. The mobility of PCBM molecules in the MDMO-PPV matrix and its crystal growth rates decrease with increased degree of confinement. In the case of free-standing films the diffusion rate of PCBM is so high that the molecule incorporation rate at the growing front of the PCBM crystals determines their growth rate; elongated single crystals are formed due to the anisotropy of the crystal growth in the lateral dimensions. For single- and double-sided confinement, the mobility of PCBM is lower, and in particular for double-sided confinement, diffusion instead of incorporation rate of PCBM molecules dominates crystal growth, which results in less elongated (single-sided confinement) and even circular (double-sided confinement) shapes of the single crystals formed. Therefore, spatial confinement reduces the mobility of PCBM molecules and thus its crystallization kinetics in its thin composite films.
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U2 - 10.1021/ma047589x
DO - 10.1021/ma047589x
M3 - Article
VL - 38
SP - 4289
EP - 4295
JO - Macromolecules
JF - Macromolecules
SN - 0024-9297
IS - 10
ER -