TY - JOUR
T1 - Suppression of the keto-emission in polyfluorene light-emitting diodes
T2 - Experiments and models
AU - Yang, Xiaohui
AU - Jaiser, Frank
AU - Neher, Dieter
AU - Lawson, Padreyia V.
AU - Brédas, Jean Luc
AU - Zojer, Egbert
AU - Güntner, Roland
AU - De Freitas, Patricia Scanduicci
AU - Forster, Michael
AU - Scherf, Ulli
PY - 2004/11
Y1 - 2004/11
N2 - The spectral characteristics of polyfluorene (PF)-based light-emitting diodes (LEDs) containing a defined low concentration of either keto-defects or of the polymer poly(9,9-octylfluorene-co-benzothiadiazole) (F8BT) are presented. Both types of blend layers were tested in different device configurations with respect to the relative and absolute intensities of green and blue emission components. It is shown that blending hole-transporting molecules into the emission layer at low concentration or incorporation of a suitable hole-transporting layer reduces the green emission contribution in the electroluminescence (EL) spectrum of the PF:F8BT blend, which is similar to what is observed for the keto-containing PF layer. We conclude that the keto-defects in PF homopolymer layers mainly constitute weakly emissive electron traps, in agreement with the results of quantum-mechanical calculations.
AB - The spectral characteristics of polyfluorene (PF)-based light-emitting diodes (LEDs) containing a defined low concentration of either keto-defects or of the polymer poly(9,9-octylfluorene-co-benzothiadiazole) (F8BT) are presented. Both types of blend layers were tested in different device configurations with respect to the relative and absolute intensities of green and blue emission components. It is shown that blending hole-transporting molecules into the emission layer at low concentration or incorporation of a suitable hole-transporting layer reduces the green emission contribution in the electroluminescence (EL) spectrum of the PF:F8BT blend, which is similar to what is observed for the keto-containing PF layer. We conclude that the keto-defects in PF homopolymer layers mainly constitute weakly emissive electron traps, in agreement with the results of quantum-mechanical calculations.
UR - http://www.scopus.com/inward/record.url?scp=10644271786&partnerID=8YFLogxK
U2 - 10.1002/adfm.200305012
DO - 10.1002/adfm.200305012
M3 - Article
AN - SCOPUS:10644271786
SN - 1616-301X
VL - 14
SP - 1097
EP - 1104
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 11
ER -