You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither SPIE nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the SPIE website.
5 December 2006Aging-induced recombination zone shift in mixed-host organic light-emitting devices
In this paper, we have demonstrated the time-dependent distribution of recombination-rate of a mixed-host (MH)
organic light-emitting devices (OLEDs) by co-evaporating an ultra thin red-emitting doped layer (probe). With various
probe position, the intensity ratio of red to green directly indicates the exciton distribution in MH layer. If the position of
probe insertion is that of maximum recombination-rate, the driving voltage is also reduced which can be explained by the
increase of the recombination current. From spectral and J-V analyses, the maximum recombination-rate position is 10
nm to the hole transporting layer when MH-OLED is not aged. After 48 hours of the DC aging test, the changes in the
red to green intensity ratio of different devices are different. After 96 hours aging, this ratio does not change further
among all devices, indicative of the achievement of steady state of recombination-rate distribution. The organic materials
degrade more when it locates near the maximum of the recombination-rate.