Pt(II) complexes with 6-(5-trifluoromethyl-pyrazol-3-yl)-2,2'-bipyridine terdentate chelating ligands: synthesis, characterization, and luminescent properties.
A series of Pt(II) complexes Pt(fpbpy)Cl (1), Pt(fpbpy)(OAc) (2), Pt(fpbpy)(NHCOMe) (3), Pt(fpbpy)(NHCOEt) (4), and [Pt(fpbpy)(NCMe)](BF(4)) (5) with deprotonated 6-(5-trifluoromethyl-pyrazol-3-yl)-2,2'-bipyridine terdentate ligand are prepared, among which 1 is converted to complexes 2-5 by a simple ligand substitution. Alternatively, acetamide complex 3 is prepared by hydrolysis of acetonitrile complex 5, while the back conversion from 3 to 1 is regulated by the addition of HCl solution, showing the reaction sequence 1-->5-->3-->1. Multilayer OLED devices are successfully fabricated by using triphenyl-(4-(9-phenyl-9H-fluoren-9-yl)phenyl) silane (TPSi-F) as host material and with doping concentrations of 1 varying from 7 to 100 %. The electroluminescence showed a substantial red-shifting versus the normal photoluminescence detected in solution. Moreover, at a doping concentration of 28 %, the device showed a saturated red luminescence with a maximum external quantum yield of 8.5 % at 20 mA cm(-2) and a peak luminescence of 47,543 cd m(-2) at 18.5 V.
Chen
Jing-Lin
JL
Department of Chemistry, National Tsing Hua University, Hsinchu (Taiwan).
Chang
Sheng-Yuan
SY
Chi
Yun
Y
Chen
Kellen
K
Cheng
Yi-Ming
YM
Lin
Chun-Wei
CW
Lee
Gene-Hsiang
GH
Chou
Pi-Tai
PT
Wu
Chen-Hao
CH
Shih
Ping-I
PI
Shu
Ching-Fong
CF