For the most common blue (aqua) phosphor, FIrpic, vacuum deposition causes partial loss of fluorine substituents from the ligands, and partial decomplexation of the picolinate (pic) ancillary ligand, this then causes further degradation over a short period of running, leaving the blue pixels with a much shorter lifetime than both the red and green. The phosphorescent emitters lack good saturated colour but more importantly the blue metal organic complexes used are unstable. In the latest generation of high-efficiency (>60 lm/W) organic solid-state lighting (OSSL) panels from Novaled, Osram, and Konica Minolta-Philips, use of all phosphorescent emitters yields very warm white colours, with poor colour temperatures of 2600 K, and poor lifetimes especially for the blue component.

The displays employ red phosphorescent emitters but blue and green fluorescent emitters. 2012), including Samsung’s fastest selling smart phone to date, the Galaxy S2. Active matrix displays using these are now found in the latest smart phones ( ca. IntroductionĬurrent state-of-the-art OLED and PLED devices have been optimised for use in displays, having small-area pixels, yielding high efficiency and good individual colour from each pixel. Further, new devices architectures open up which are simple and have intrinsically low turn on voltages, ideal for large-area OLED lighting applications. These triplet contributions can give very high device yields for fluorescent emitters, which in the case of blue devices can be highly advantageous. The materials requirements to obtain maximum singlet production from triplet states are discussed.

Here, the various routes by which triplet excitons can generate singlet states are discussed and their relative contributions to the overall electroluminescence yield are given. (2006)), which have been verified as being part due to direct singlets formed on recombination and part from triplet fusion, singlets produced during triplet annihilation (Kondakov et al. (2003)) or are singlet excitons generated in secondary processes? Direct measurement of the singlet generation rate in working devices of 44% has been shown (Rothe et al. Thus, the question arises is recombination spin dependent (Tandon et al. Recent device results, however, show that this limit does not hold and far higher efficiencies can be achieved in purely fluorescent-based systems (Wohlgenannt et al. A potential major drawback with organic light-emitting devices, (OLEDs) is the limit of 25% singlet exciton production through spin-dependent charge recombination.

Suitcase fusion 7 pfb