Stable Single-Layer Light-Emitting Electrochemical Cell Using 4,7-Diphenyl-1,10-phenanthroline-bis(2-phenylpyridine)iridium(III) Hexafluorophosphate

Abstract

A significant improvement in the stability of a light emitting electrochemical cell was achieved by utilizing a novel iridium(III) complex: 4,7-diphenyl-1,10-phenanthroline-bis(2-phenylpyridine)iridium(III) hexafluorophosphate. The enhanced device stability is correlated by means of DFT studies to be related to a more efficient shielding of the reactive LUMO of the complex.

Long‐Living Light‐Emitting Electrochemical Cells – Control through Supramolecular Interactions

“…Therefore, a more correct way is to take the time starting just after the pre-biasing phase, thus from the point when the device is biased at 3 V, until it reaches t 1/2 , which is extrapolated to be beyond 3000 hours. Compared to the device lifetime obtained when using the parent complex, [Ir(ppy) 2 (bpy)][PF 6 ], which is approximately 30 hours, [17] this value is an enormous improvement. The remarkable properties of our device are also demonstrated by the total photon flux emitted by the device.…”

“…Although no detailed study exists for iridium(III)-based iTMC devices, the use of more hydrophobic complexes significantly increased the device lifetime, indicating that the intrinsic stability of the complex is also in this case the limiting factor. [17] Supramolecular interactions, such as p-stacking, between coordinated ligands of a single complex can potentially enhance its stability. For example they are known to influence the photophysical properties of copper-based iTMCs incorporating 2-aryl-or 2,9-diaryl-1,10-phenanthroline ligands.…”

“…For example they are known to influence the photophysical properties of copper-based iTMCs incorporating 2-aryl-or 2,9-diaryl-1,10-phenanthroline ligands. [18,19] In this work, we describe the preparation and characteristics of a supramolecularly caged ionic iridium(III) complex [Ir(ppy) 2 [17] this lifetime is an enormous improvement and sufficient for first applications. The prototype supramolecular complex was prepared using methods similar to those for other [Ir(ppy) 2 Table 1) are similar, with the main difference being the lower photoluminescence quantum efficiency in a polymethylmethacrylate thin film, 37% versus 66%, respectively.…”

Functional IrIII Complexes and Their Applications

“…This leads to a diverse range of emission colors from Ir III complexes. [4][5][6] Thus, Ir III complexes have been widely studied for many applications including organic light-emitting diodes (OLEDs), [7][8][9][10][11] light-emitting electrochemical cells (LECs), [12] luminescence sensitizers, [13,14] biological labeling, [15,16] and chemosensors. [16][17][18][19][20][21] In pursuit of a highly emissive Ir III complex, many heteroleptic complexes of the type [Ir(C^N) 2 MLCT transitions.…”

Efficient Polymer Light‐Emitting Diode Using Air‐Stable Metal Oxides as Electrodes

“…Some examples exist; however these devices rely on the presence of ionic charges to generate a dipole across the metal-light-emitting layer interface, and their reported lifetimes are low. [3][4][5] Metal oxides hold, in principle, the promise of good charge injection, as they combine properties such as high transparency, good electrical conductivities, tuneable morphology, and the possibility of deposition on large areas with low-cost techniques. Recently, reports concerning the use of metal oxides as charge-injection layers for OLEDs were published.…”