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

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• 作者：Guang-Zhao Lu ; Yi-Ming Jing ; Hua-Bo Han ; Yu-Liang Fang ; You-Xuan Zheng
• 刊名：Organometallics
• 出版年：2017
• 出版时间：January 23, 2017
• 年：2017
• 卷：36
• 期：2
• 页码：448-454
• 全文大小：521K
• ISSN：1520-6041

文摘

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 (λ_max 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 (η_max,c) of 55.6 cd A^–1, a maximum power efficiency (η_max,p) of 52.2 lm W^–1, and a maximum external quantum efficiency (EQE_max) of 18.0%. Device G2 with the Pt2 emitter displayed lower efficiency rolloff with η_c 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.