Efficient, Saturated Red Organic Light Emitting Devices Based on Phosphorescent Platinum(II) Porphyrins

Abstract

Two new platinum(II) porphyrins have been synthesized and their luminescent properties have been studied. The platinum porphyrins exhibited strong phosphorescence in the red with narrow line widths. When they were doped into aluminum(III) tris(8-hydroxyquinolate) (AlQ3) in the electron-transporting and -emitting layer of an organic light-emitting device, energy transfer occurred between the host AlQ3 and the platinum porphyrin. Bright saturated red emission with high efficiency at low to moderate current density has been achieved. In the high current regime, the electroluminescence efficiency decreased and the perceived emission color blue shifted as a result of mixed emission from the platinum porphyrin and AlQ3. This current dependence was due to the saturation of triplet emissive sites, because of the long-lived phosphorescence state of the platinum porphyrin complex.

Structural, Photophysical, and Electrophosphorescent Properties of Platinum(II) Complexes Supported by Tetradentate N2O2 Chelates

“…The N 2 O 2 ligand framework is devised with chemically inert functionalities and the considerable chelate effect should ensure good thermal stability. Phenyl and tert-butyl substituents are appended to the Pt(N 2 O 2 ) moiety, since coordinatively unsaturated squareplanar Pt II compounds are known to engage in excited-state and exciton self-quenching reactions in solution [11] and EL devices, [12] respectively. The nature of these substituents may therefore yield emitting layers with different quenching behavior as well as other relevant physical properties.…”

Deep-red electrophosphorescence from a platinum(II)–porphyrin complex copolymerised with polyfluorene for efficient energy transfer and triplet harvesting

“…Such emission may be related to oxidative defects on the PFO [23] and to the emission from MPP(Pt) singlet state, as reported for similar Pt(II)-porphyrin complexes at 580 nm. [26,27] For MPP(Pt) loadings above 1%, copolymers show a pure electrophosphorescence (P3 and P4). The current-voltage and radiance-voltage characteristics are shown in Figure 4(b), and a summary of the LEDs performance is reported in Table 2.…”

Synthesis and Characterization of New Thienopyrazine‐cored Dendrimer for Non‐Doped Organic Red Light‐Emitting Diodes

“…Moreover, the EL spectra and CIE coordinates almost kept unchanged with increasing driving voltage, which offers better device operation compared to red OLEDs with dopants in which the color usually changes with voltage. 20 The voltage-current density-brightness characteristics of D2TP device are shown in Figure 3 …”