Open AccessEffects of magnetic field on organic electroluminescence
Author(s) -
Jin Wang,
Jie Hua,
Ding Gui-ying,
Xi Chen,
Gang Zhang,
Wenlong Jiang
Publication year - 2009
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.58.7272
Subject(s) - electroluminescence , oled , materials science , optoelectronics , zeeman effect , magnetic field , luminescence , singlet state , triplet state , diode , photochemistry , atomic physics , excited state , chemistry , nanotechnology , physics , layer (electronics) , quantum mechanics
Electrofluorescent organic light-emitting device with the structure of ITO/NPB/Alq3/LiF/Al and electrophosphorescent device with the structure of ITO/NPB/CBP: Irppy3/BCP/Alq3/LiF/Al were fabricated. Their electroluminescence properties were measured under an external magnetic field of 50 mT. Compared to the case of without magnetic field, the electroluminescentEL efficiencies of the above-mentioned two kinds of devices increase 44% and 7%, respectively. Based on the luminescence mechanism of organic light-emitting diodes OLEDs, the observed phenomena were explained. The origin of the improvement can be attributed to the Zeeman split of triplet state due to the external magnetic field influence, resulting in the conversion of triplets T+ into singlet S in the electrofluorescent device and an increase of the rate constants of triplet energy transfer from host to guest in electrophosphorescent device, respectively. At the same time, the reduced concentrations of triplet decreases the interaction of triplets with free carriers, resulting in an increase in the mobility of free carriers within the device and hence increasing the current.