Quenching effects in organic electroluminescence - Publikacja - MOST Wiedzy

Wyszukiwarka

Quenching effects in organic electroluminescence

Abstrakt

We examine various electronic processes that underlie the quenching of the emission from highly efficient phosphorescent and electrophosphorescent organic solid-state molecular systems. As an example, we study the luminescent efficiencies from the phosphorescent iridium (III) complex, fac tris (2-phenylpyridine) iridium [(Ir (ppy)3] doped into a diamine derivative doped polycarbonate hole-transporting matrix and in the form of vacuum-evaporated films, as a function of electric field. We demonstrate that the observed decrease in electrophosphorescence efficiencies at high electric fields, and electric-field-induced quenching of phosphorescence from neat [(Ir (ppy)3] solid films is due to the field-assisted dissociation of Coulombically correlated electron hole (e-h) pairs. They are formed in a bimolecular recombination process prior to the formation of emissive triplet excitons, or are charge-transfer (CT) states originating from the localized electronic excited states as a result of the initial charge separation upon photoexcitation, respectively. It is found that the high-field dependence of the quenching efficiency in both cases follows the three-dimensional Onsager theory of geminate recombination, the fit yielding the initial intercarrier distance (r0) of the carrier pairs. We find re-h>3.5 nm for the triplet exciton precursor pairs in the bimolecular recombination, and r CT=1.8+0.1 nm for the initial carrier separation from the photo-excited electronic states. Triplet-triplet and triplet-charge carrier annihilation processes are shown to play major roles in the decrease of the electrophosphorescence efficiency within the lower-field regime at lower current densities. Summarizing the results allows us to point out some emitter features important for identifying phosphors useful for practical electroluminescent devices.

Cytuj jako

Pełna treść

pełna treść publikacji nie jest dostępna w portalu

Słowa kluczowe

Informacje szczegółowe

Kategoria:
Publikacja w czasopiśmie
Typ:
artykuł w czasopiśmie z listy filadelfijskiej
Opublikowano w:
PHYSICAL REVIEW B nr 66, wydanie 23, strony 1 - 15,
ISSN: 1098-0121
Język:
angielski
Rok wydania:
2002
Opis bibliograficzny:
Kalinowski J., Stampor W., Mężyk J., Cocchi M., Virgili D., Fattori V.: Quenching effects in organic electroluminescence// PHYSICAL REVIEW B. -Vol. 66., iss. 23 (2002), s.1-15
Weryfikacja:
Politechnika Gdańska

wyświetlono 37 razy

Publikacje, które mogą cię zainteresować

Meta Tagi