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Article Dans Une Revue ChemPhysChem Année : 2005

Impact of structure and morphology on charge transport in semiconducting oligomeric thin-film devices

Résumé

We investigated various thin-film morphologies of vacuum-deposited highly luminescent 2,5-di-n-octyloxy-1,4-bis[4'-(styryl)styryl]benzene (Ooct-OPV5) in a typical light-emitting-diode device structure. Important modifications in the thin-film morphology and structure were obtained by changing the substrate temperature in the range 23-90 degrees C. Structural analysis by X-ray and electron diffraction provided clear evidence for polymorphism in evaporated thin films of Ooct-OPV5. Concomitantly, the hole mobility in the corresponding devices was determined by transient electroluminescence measurements. We demonstrate that the substrate temperature T-sub is a key parameter that controls the hole mobility of the devices. Increasing T-sub between 23 and 84 degrees C results in a progressive increase of the zero-field hole mobility from 10(-6) to 10(-4) cm(2) V-1 s(-1). The increase in hole mobility is correlated to the average grain size in the thin films. In addition, we give evidence for the existence of a peculiar growth mode in the bulk crystal structure of Ooct-OPV5, whereby the (a,b) and (b,c) planes con grow in a homoepitaxial manner.

Dates et versions

hal-00379930 , version 1 (29-04-2009)

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Citer

C. Melzer, Martin Brinkmann, W. Krasnikov, Georges Hadziioannou. Impact of structure and morphology on charge transport in semiconducting oligomeric thin-film devices. ChemPhysChem, 2005, 6 (11), pp.2376-2382. ⟨10.1002/cphc.200500142⟩. ⟨hal-00379930⟩
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