20‐2: High Efficiency and Long Device Lifetime Green Organic Light Emitting Diodes using a Pt Complex

Abstract

A High-performance top-emitting green phosphorescent OLED with a long operational lifetime, an LT of 200% longer and with a high current efficiency, 118% higher than the devices with state-of-the art Ir complexes at the luminance of 15,000 cd m −2 , was realized using a developed Pt complex and new hole transporting buffer and exciplex host materials. To the best of our knowledge, the current efficiency and lifetime of our achievements at this high luminance are more than 1.5 times higher and 100 times longer, respectively, than those of green phosphorescent OLEDs with Pt complexes from literatures and materials companies in the world. This high current efficiency was achieved with higher horizontal transition dipole ratio, 86%, and short decay time, 2.4 μs, of our own developed Pt complex.

61‐1: Heuristics of OLED and Micro LED Efficiencies

“…The EQEs for red, green, and blue OLEDs based on the state-ofthe-art "product" OLED power efficiency shown in Figure 2 are below the envelope curve in Figure 5. This may be understood given the reported difficulties associated with achieving maximum EQE and maximum lifetime at the same time [11][12][13][14][15]. curve by 2, a heuristic that is based on experimental observations [28,32].…”

“…Next generation OLED displays demand high energy efficiency [2][3][4][5][6][7][8][9][10], but it is a hard challenge for the OLED displays to meet the needs for high efficiency, color accuracy, and long lifetime simultaneously [2,[11][12][13][14][15]. Therefore, inorganic LED (ILED or µLED) display technology is under research and development by several companies worldwide [16][17][18][19][20][21][22][23][24][25][26][27][28].…”

Stable Tetradentate Gold(III)‐TADF Emitters with Close to Unity Quantum Yield and Radiative Decay Rate Constant of up to 2 × 106s−1: High‐Efficiency Green OLEDs with Operational Lifetime (LT90) Longer than 1800 h at 1000 cd m−2

“…The development of emitters that simultaneously demonstrate high maximum external quantum efficiency (EQE max ), small efficiency roll‐offs, and long operational lifetimes at practical luminances is essential for commercial pursuits in organic light‐emitting diodes (OLEDs); however, such leading candidates have been dominated by a limited set of emissive materials in literature, such as the precious‐metal‐containing Ir(III) and Pt(II) complexes, [ 1 ] which urges the quest for new competitive candidates for more sustainable OLED developments. Gold(I) and gold(III) emitters have been extensively studied in recent years, owing to the strong gold–ligand bond that confers high thermal stability, large spin–orbit coupling (SOC) constants for harvesting triplet excitons, and higher earth abundance than the other precious noble metals; however, at a practical luminance of 1000 cd m −2 , the operational lifetimes of reported high‐efficiency OLEDs based on gold complexes are far from satisfaction.…”

“…[ 2 ] Rigid tetradentate ligand scaffolds are conceived to suppress excited‐state structural distortion and improve the thermal stability of metal complexes, which are both crucial to enhance transition metal complex based device operational stability. Since thermally stable tetradentate platinum(II) complexes have been demonstrated to exhibit long operational lifetimes at practical luminance levels in OLEDs, [ 1a,b ] tetradentate gold(III) complexes, having similar d 8 square‐planar geometry with strong gold–ligand bonds, are anticipated to possess high thermal stability and extended operational lifetimes. In our previous work, the first example of a class of tetradentate thermally activated delayed fluorescent (TADF) gold(III) complexes has been developed, which exhibit high photoluminescence quantum yields ( Φ ) of up to 90% and radiative decay rate constants ( k r ) on the order of 10 5 s −1 .…”

19‐2: Design Heuristics of Color Conversion Films in Micro LED Displays

“…Next generation OLED displays demand high energy efficiency [1][2][3][4][5][6][7], but it is a hard challenge for the OLED displays to meet the needs for high efficiency, color accuracy, and long lifetime simultaneously [8][9][10][11][12]. Therefore, inorganic LED (µLED) display technology is under research by several companies worldwide [13][14][15][16][17][18][19][20][21].…”