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Study of energy transfer from excited TPD to Alq in organic electroluminescent devices by time‐resolved fluorescence spectroscopy using a scanning near‐field optical atomic force microscope
Author(s) -
Yamamoto N.,
Muramatsu H.,
Do L.M.,
Han E.M.,
Kato T.,
Fujihira M.
Publication year - 2001
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.2001.00813.x
Subject(s) - electroluminescence , materials science , excited state , optoelectronics , kelvin probe force microscope , microscope , near field scanning optical microscope , optical microscope , spectroscopy , oled , microscopy , analytical chemistry (journal) , optics , chemistry , scanning electron microscope , nanotechnology , atomic physics , atomic force microscopy , physics , layer (electronics) , quantum mechanics , chromatography , composite material
We demonstrate the direct measurement of molecular diffusion at organic/organic interfaces of organic electroluminescence devices by use of a scanning near‐field optical atomic force microscope. Our preliminary study shows that the degradation of an electroluminescence device is partly caused by crystallization of the organic layers. Because the initial stage of degradation cannot be observed by microscopic methods, nanoscale optical properties of the interface in multilayer systems are currently receiving a great deal of attention. Defects of organic electroluminescence devices were investigated using a scanning near‐field optical atomic force microscope. This instrument is capable of measuring both a topographic and a fluorescence image at the same time. The defect area and other areas are clearly observed and time‐resolved near‐field fluorescence spectra demonstrate emission of the different species. These results suggest that defects occur at the organic solid interface, and that energy transfer occurs from excited TPD, as donor, to Alq, as acceptor.