Combinatorial fabrication and studies of intense efficient ultraviolet–violet organic light-emitting device arrays

Abstract

Arrays of ultraviolet–violet (indium tin oxide)/[copper phthalocyanine (CuPc)]/[4,4′-bis(9-carbazolyl)biphenyl (CBP)]/[2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4oxadiazole (Bu-PBD)]/CsF/Al organic light-emitting devices, fabricated combinatorially using a sliding shutter technique, are described. Comparison of the OLED electroluminescence and CBP photoluminescence spectra indicates that the emission originates from the bulk of that layer. In arrays of devices in which the thickness of the CuPc and Bu–PBD were varied, but that of CBP was fixed at 50 nm, the optimal radiance R was obtained at CuPc and Bu–PBD thicknesses of 15 and 18 nm, respectively. At 10 mA/cm2, R was 0.38 mW/cm2, i.e., the external quantum efficiency was 1.25%; R increased to ∼1.2 mW/cm2 at 100 mA/cm2.

Copper-phthalocyanine based metal–organic interfaces: The effect of fluorination, the substrate, and its symmetry

“…37 Previous work reported the disappearance of the Au(111) herringbone reconstruction under the F 16 CuPc monolayers. 26 However, higher quality STM measurements have now proven the opposite, revealing the substrate reconstruction under the organic overlayer with an fcc/hcp periodicity measured along the [1][2][3][4][5][6][7][8][9][10] direction of 65 ± 3 Å, thus virtually unchanged with respect to the pristine Au(111). While this could be interpreted as the result of very weak molecule-substrate interactions, 31 the reported disappearance of the Au(111) surface state upon F 16 CuPc adsorption, as measured by valence band photoelectron spectroscopy, 26 still supports the picture of a significant interaction.…”

“…31,38 CuPc on Au(111) leads to the growth of crystalline layers characterized by a square unit cell of dimensions a = 13.9 ± 0.7 Å, and it hardly affects the underlying Au(111) surface reconstruction. 30,39 The unit cell vectors are directed along the high symmetry and [1][2][3][4][5][6][7][8][9][10] directions (Fig. 4).…”

Spectrally narrowed edge emission from organic light-emitting diodes

“…The organic layers, CsF buffer layer, 8 and Al cathode were deposited using a combinatorial sliding shutter technique described previously. 7 Thus, the Al cathode was deposited through a shadow mask containing 21ϫ 21 1.5 mm diameter circular holes. 1 mm wide stripes, up to 25 mm long, were fabricated by evaporating the Al through an appropriate mask.…”

“…The R ᮀ ϳ 20 ⍀ / ᮀ, 140 nm thick ITO-coated 2 ϫ 2 in. 2 glass substrates were cleaned as described elsewhere 7 and UV-ozone treated. The organic layers, CsF buffer layer, 8 and Al cathode were deposited using a combinatorial sliding shutter technique described previously.…”

Spectrally narrowed edge emission from leaky waveguide modes in organic light-emitting diodes

“…2 glass substrates were cleaned by detergent and organic solvents and then treated in a UV/ozone oven to increase the ITO work function and facilitate hole injection, as described elsewhere. [11][12][13] The organic layers, CsF buffer layer, 14,15 and Al cathode were deposited in a thermal vacuum evaporation chamber ͑background pressure Ͻ5 ϫ 10 −6 Torr͒ installed in an Ar-filled glove box. The organic layers typically included a copper phthalocyanine ͑CuPc͒ hole injecting layer, an N , NЈ-diphenyl-N , NЈ-bis͑1-naphthylphenyl͒-1,1Ј-biphenyl-4 , 4Ј-diamine ͑NPD͒ hole transport layer ͑HTL͒, the emitting layer of variable thickness, and a tris͑quinolino-late͒ Al ͑Alq 3 ͒ electron transport layer ͑ETL͒ or 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline ͓bathocuproine ͑BCP͔͒ ETL and hole-blocking layer.…”