Highly efficient orange organic light-emitting diodes using a novel iridium complex with imide group-containing ligands

Abstract

We report the synthesis and device characterization of a novel iridium complex using a phenylpyridine derivative containing an imide functional group as a bis-cyclometallized ligand ((impy) 2 Ir(acac)) for orange organic light-emitting diodes (OLEDs). The photoluminescence of the dopant emits orange light with the main peak of 560 nm and a shoulder of 595 nm. The OLEDs made with the synthesized dopant also produce intense orange electroluminescence at 568-572 nm wavelengths depending on the device geometry. Very high peak external quantum efficiencies of 13.8-14.4%, peak power efficiencies of 29.2-32.7 lm/W, and low operation voltages of 5.3-5.4 V at 1000 cd/m 2 have been demonstrated for the orange OLEDs.Scheme 1 Synthesis of iridium(III) bis(2-isopropyl-5-(pyridin-2-yl)isoindoline-1,3-dione-N,C 2 0 )(acetyl acetonate).

Management of Singlet and Triplet Excitons in a Single Emission Layer: A Simple Approach for a High‐Efficiency Fluorescence/Phosphorescence Hybrid White Organic Light‐Emitting Device

“…On the other hand, the 10 wt% Ir(2‐phq) 3 doped DADBT device also shows outstanding EL performance with EQE, CE and PE at their maximum values of 17.2%, 32.7 cd A −1 and 41.1 lm W −1 , respectively, and they remain to be 16.7%, 31.8 cd A −1 and 33.3 lm W −1 at 100 cd m −2 . Considering the theoretic limits of 5% for fluorescent OLEDs and 20% for phosphorescent OLEDs,5a these performances are among the best for either sky‐blue fluorescent OLEDs,8, 11 or orange phosphorescent OLEDs reported in literatures 2h, 12. These confirm that DADBT is a good blue fluorophor and also an ideal host for orange phosphor.…”

Highly Efficient Orange and White Organic Light‐Emitting Diodes Based on New Orange Iridium Complexes

“…The device performance of the (CF 3 ‐bt) 2 Ir(acac)‐based device C is quite encouraging, with a maximum luminance ( L max ) of 80 190 cd m −2 at 12 V, a η L of 76.0 cd A −1 at 6 V, and a η p of 39.8 lm W −1 at 6 V. The (F‐bt) 2 Ir(acac)‐doped device D also exhibited remarkable efficiency with a peak η L of 71.6 cd A −1 and an even higher η p of 44.9 lm W −1 at 5 V. The detailed device performances are summarized in Table 1 . The high luminance efficiency of 76.0 cd A −1 that was observed for the orange OLEDs is almost double the highest value previously reported for orange OLEDs 9, 10, 12. The power efficiency of 44.9 lm W −1 is also the highest reported for orange OLEDs to date.…”

Interface Engineering in Organic Electronics: Energy‐Level Alignment and Charge Transport

“…Table 1 shows the orientation‐dependent IE of several organic semiconductor films in the literature, determined both experimentally and theoretically. [ 58–60,64–82 ] The IE of random‐oriented molecules in films is also included for compounds such as the N , N ′‐bis(naphthalen‐1‐yl)‐ N , N ′‐bis(phenyl)benzidine (NPB) prepared by vacuum thermal evaporation. Therefore, the IE measurement of organic semiconductor film by UPS can serve as a complementary method to evidence the molecular orientation measured by other techniques such as the VASE.…”