Novel cyclometalated platinum (II) complex containing alkyl-trifluorene picolinic acid as emitter for single-layer white PLEDs

To explore the influence of molecular structure on formation excimers and obtain high-efficiency white polymer light-emitting devices, two novel blue-emitting cyclometalated platinum (II) complexes of (dfppy)Pt(Tfl-pic) and (C(16)dfppy)Pt(Tfl-pic) have been successfully synthesized and characterized, where dfppy is 2-(2,4-difluoro-phenyl)pyridine, C(16)dfppy is 5-hexdecanyl-2-(2,4-difluorophenyl)pyridine and Tfl-pic is alkyltrifluorene-containing picolinic acid derivative. Compare to (dfppy)Pt(pic), both of platinum (II) complexes exhibited high thermal stability, good solubility and excellent photoluminescent quantum efficiency (about 94% +/- 10%) at room temperature. Deep blue emission at about 418 nm in dilute dichloromethane (10 (5) M) and red-shifted emission at about 619 nm in the neat film were observed under opto-excitation. Pure white light with a CIE coordinates (0.33, 0.33) at 10 V was obtained in the (dfppy)Pt(Tfl-pic)-doped devices and a red emission was obtained in the (C(16)dfppy)Pt(Tfl-pic)-doped devices with the same device configuration using a blend of polyvinylcarbazole and 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole as a host matrix, respectively. (C) 2010 Elsevier B. V. All rights reserved.