Naslov
Charge dynamics and recombination at organic heterojunctions in OLEDs

Autori
Jurić, Ivan ; Tutiš, Eduard ; Batistić, Ivo

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
ICEL 7, Programs and Abstracts / - , 2008, 154-154

Skup
The 7th International Conference on Electroluminescence of Molecular Materials and Related Phenomena

Mjesto i datum
Dresden, Njemačka, 02.09.2008. - 06.09.2008

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
heterojunction; recombination; exciton; exciplex

Sažetak
The processes at the organic heterojunctions differ much from those in the bulk, and organic multilayer devices derive many of their advantages from this difference. Here we present a three-dimensional modeling, numerical simulations, and a discussion of transport and recombination in a system with a heterojunction. Partial cross-sections for the formation of excitons and exciplexes are considered in particular, as well as probabilities for recombination in the respective channels. We examine the influence of the energy barrier, electric field, structural and site-energy disorder at an organic/organic interface on transport and recombination. As the energy barrier at the heterojunction rises, the motion of the electrons and holes across the heterojunction surface becomes increasingly correlated. The crossing of the heterojunction by one carrier type is then dominated by sites where the carriers of opposite sign can assist. This amplifies the probability of recombination, first in the exciton and then, as the barrier further rises, in the exciplex channel. We found a simple relation between the cross-sections in the exciplex and the exciton channels, which applies for a wide range of device parameters. It portrays well the maxima we found for the recombination in the exciton channel, regarded either as a function of barrier height or of applied electric field. Since excitons usually have a larger light-yield, such maxima represent OLEDs with optimal efficiency. We have also investigated influence of the site-energy disorder and the roughness of the organic-organic interface. We found that roughness has a much stronger impact than site-energy disorder, especially on the relative probability for the creation of excitons or exciplexes.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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