Edge-emission detection system.
The angle-dependent VSL measurement setup.
(a) Edge and (b) surface emission from glass/[ ITO]/[5 nm CuPc]/[45 nm NPD]/[ nm Alq3]/[1 nm CsF]/Al OLEDs, where , 85, 105, 125, and 145 nm.
Edge-emission spectrum of a glass/[ ITO]/[5 nm CuPc]/[45 nm NPD]/[120 nm DPVBi]/[7 nm Alq3]/[1 nm CsF]/Al OLED.
Edge-emission EL spectra of ITO/[5 nm CuPc]/[40 nm NPD]/[ nm 1:1 NPD:spiro-DPVBi]/[40 nm spiro-DPVBi]/[8 nm Alq3]/[1 nm CsF]/Al OLEDs, , 30, 50, 70, and 90 nm.
The edge-emission intensity vs polarization angle in polar coordinates: the solid line is the experimental data, the dashed line is the theoretical data fitting by Eq. (1).
A drop of various liquids is placed between a photoexcited spot of the emitting film and the edge. If the edge emission is due to waveguide modes in the organic and ITO layers (top figure), then the change in the index of the cladding layer will strongly distort the edge-emission spectrum, since reflections on the upper boundary control the phase condition for mode selection. If the edge emission is due to the leaky modes in the glass substrate (bottom figure), the change in the cladding layer index will have no effect on the mode, because all energy flux has leaked into the substrate.
PL Edge-emission spectra of (a) glass/ITO/[ nm DPVBi] and (b) glass/ITO/[ nm DPVBi]/Al, with , 76, 91, 106, and 121 nm, photoexcited at 363 nm (see the small peak at that wavelength) by an .
Glass/[ ITO]/[5 nm CuPc]/[40 nm NPD]/[60 nm DPVBi]/[6 nm Alq3]/[1 nm CsF]/[100 nm Ag (solid line) or Al (dotted line)]/Al. Note that the FWHM of the device with a Ag cathode is half that of the device with an Al cathode.
The simulated asymmetric slab waveguide modes.
Dotted line: the surface emission spectra, which is assumed to be the spectrum of the light emitted in the organic film. Dashed line: the observed SNEE. Solid line: the simulated leaky waveguide mode spectrum.
The normalized (left) and un-normalized (right) edge-emission spectra from DPVBi OLEDs with stripe length from . The arrows indicate increasing stripe length.
The intensity of the peak of the TE mode vs the OLED stripe length. The black squares are the experiment data, and the curve is the fit of Eq. (5) to the data.
(a) Edge-emission spectra vs stripe length . (b) The peak TE mode edge-emission intensity vs . (c) The FWHM of the TE mode edge-emission spectrum vs .
The peak edge-emission intensity vs the stripe length at different voltages, the lines are the best fits of the function .
The FWHM of the TE mode edge-emission spectrum vs the stripe length .
ITO layer (black area) is patterned into a staircase-type in steps. Rectangular Al cathodes (gray area) are deposited. The overlapped area defines OLED devices.
Edge-emission spectra of an OLED with the device structure: glass/ITO/[5 nm CuPc]/[45 nm NPD]/[61 nm DPVBi]/[9 nm Alq3]/[1 nm CsF]/Al, the excitation stripe length l is varied from 100 to .
The intensity vs stripe length at detection angles of 0°, −5°, and −10°.
The FWHM of the edge-emission spectrum at detection angles from −25° to 60°.
FDTD-predicted intensity of edge emission for various sample lengths.
Intensity profiles of modes excited at (a) top: , (b) center: , and (c) bottom: .
(a) Surface and (b) edge-emission spectra of Ir(ppy)3 OLEDs with various emitting layer thicknesses. (c) The magnification of the edge-emission spectra.
(a) Surface and (b) edge-emission decay time of Ir(ppy)3 OLEDs with different emitting layer thicknesses at different bias.
(a) Surface and (b) edge-emission spectra of FIrpic OLEDs with different thicknesses. (c) The lifetime of the edge (dot) and surface (square) emission.
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