Efficient Electroluminescence of Two Heteroleptic Platinum Complexes with a 2‑(5-Phenyl-1,3,4-oxadiazol-2-yl)phenol Ancillary Ligand

• Published in: Organometallics Vol. 36; no. 2; pp. 448 - 454
• Main Authors: Lu, Guang-Zhao, Jing, Yi-Ming, Han, Hua-Bo, Fang, Yu-Liang, Zheng, You-Xuan
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 23.01.2017; Amer Chemical Soc
• Subjects: Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Physical Sciences; Science & Technology; IR(III) COMPLEXES; PHOTOLUMINESCENCE; IRIDIUM COMPLEXES; CARRIER MOBILITY; PERFORMANCE; LIGHT-EMITTING DEVICES; DIODES; TETRAPHENYLIMIDODIPHOSPHINATE; EMITTERS; GREEN
• ISSN: 0276-7333; 1520-6041
• DOI: 10.1021/acs.organomet.6b00851

Two new platinum­(II) cyclometalated complexes with 2-phenylpyridine (Pt1) and 2-(4-trifluoromethyl)­phenylpyridine (Pt2) as the main ligands and 2-(5-phenyl-1,3,4-oxadiazol-2-yl)­phenol (pop) as the electron-transporting ancillary ligand were developed. The photoluminescence quantum efficiency yields of both green Pt1 and Pt2 phosphors (λmax 490 and 496 nm) are 20.0% and 31.0% in CH2Cl2 solutions, respectively. Efficient OLEDs (organic light emitting diodes) of ITO/TAPC (bis­[4-(N,N-ditolylamino)­phenyl]­cyclohexane, 40 nm)/Pt1 or Pt2 (5 wt %):TCTA (4,4′,4″-tri­(carbazoyl-9-yl)­triphenylamine, 10 nm)/Pt1 or Pt2 (5 wt %):2,6DCzPPy (2,6-bis­(3-(carbazol-9-yl)­phenyl)­pyridine, 10 nm)/TmPyPB (1,3,5-tris­(m-pyrid-3-ylphenyl)­benzene, 40 nm)/LiF (1 nm)/Al (100 nm) were fabricated. Particularly, device G1 based on complex Pt1 with 5 wt % doped concentration showed superior performance with a maximum current efficiency (ηmax,c) of 55.6 cd A–1, a maximum power efficiency (ηmax,p) of 52.2 lm W–1, and a maximum external quantum efficiency (EQEmax) of 18.0%. Device G2 with the Pt2 emitter displayed lower efficiency rolloff with ηc values of 48.5 and 43.1 cd A–1 as the luminance reached 5000 and 10000 cd m–2, respectively. These research results demonstrate that the Pt­(II) complexes with an ancillary ligand attached with the 1,3,4-oxadiazole group have promising applications in efficient OLEDs.