TY - GEN
T1 - Spectrally narrowed edge emission from leaky waveguide modes in OLEDs
AU - Gan, Z. Q.
AU - Tian, Y.
AU - Lynch, D. W.
AU - Kang, Ji Hun
AU - Park, Q. Han
AU - Shinar, J.
PY - 2007
Y1 - 2007
N2 - A dramatic spectral line narrowing of the edge-emission, at room temperature, from tris(quinolinolate) Al (Alq3), N,N'-diphenyl-N,N'- bis(1-naphthylphenyl)-1,1 '-biphenyl-4,4'-diamine (NPD), 4,4'-bis(2,2'-diphenyl- vinyl)-1,1'-biphenyl (DPVBi), and some guest-host small molecular OLEDs, fabricated on ITO-coated glass, is described. In all but the DPVBi OLEDs, the narrowed emission band emerges above a threshold thickness of the emitting layer, and narrows down to a full width at half maximum of only 5-10 nm. The results demonstrate that this narrowed emission is due to irregular waveguide modes that leak from the ITO to the glass substrate at a grazing angle. While measurements of variable stripe length (l) devices exhibit an apparent weak optical gain, there is no observable threshold current or bias associated with this spectral narrowing. It is suspected that the apparent weak optical gain is due to misalignment of the axis of the waveguided mode and the axis of the collection lens of the probe, but it is not clear if such a misalignment can account for the for the observed evolution of the edge emission spectra with l.
AB - A dramatic spectral line narrowing of the edge-emission, at room temperature, from tris(quinolinolate) Al (Alq3), N,N'-diphenyl-N,N'- bis(1-naphthylphenyl)-1,1 '-biphenyl-4,4'-diamine (NPD), 4,4'-bis(2,2'-diphenyl- vinyl)-1,1'-biphenyl (DPVBi), and some guest-host small molecular OLEDs, fabricated on ITO-coated glass, is described. In all but the DPVBi OLEDs, the narrowed emission band emerges above a threshold thickness of the emitting layer, and narrows down to a full width at half maximum of only 5-10 nm. The results demonstrate that this narrowed emission is due to irregular waveguide modes that leak from the ITO to the glass substrate at a grazing angle. While measurements of variable stripe length (l) devices exhibit an apparent weak optical gain, there is no observable threshold current or bias associated with this spectral narrowing. It is suspected that the apparent weak optical gain is due to misalignment of the axis of the waveguided mode and the axis of the collection lens of the probe, but it is not clear if such a misalignment can account for the for the observed evolution of the edge emission spectra with l.
UR - http://www.scopus.com/inward/record.url?scp=42149102627&partnerID=8YFLogxK
U2 - 10.1117/12.739247
DO - 10.1117/12.739247
M3 - Conference contribution
AN - SCOPUS:42149102627
SN - 9780819468031
T3 - Proceedings of SPIE - The International Society for Optical Engineering
BT - Organic Light Emitting Materials and Devices XI
T2 - Organic Light Emitting Materials and Devices XI
Y2 - 26 August 2007 through 29 August 2007
ER -