Fabrication Of OLEDs Research Articles

25.2: Achieving Three‐Peak White Organic Light‐Emitting Devices Using Wavelength‐Selective Mirror Electrodes

AbstractWe have developed an effective approach based on wavelength‐selective mirrors to implement three‐peak WOLEDs that have EL spectra matching better with transmission spectra of typical color filters and thus give much enhanced color gamut for full‐color OLED display applications. The wavelength‐selective mirror used is highly compatible with OLED fabrication.

Osmium‐ and Ruthenium‐Based Phosphorescent Materials: Design, Photophysics, and Utilization in OLED Fabrication

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

Novel Photo‐Crosslinkable Light‐Emitting Rod/Coil Copolymers: Underlying Facile Material for Fabricating Pixelated Displays

AbstractSummary: Photo‐crosslinkable PF‐b‐PCEA triblock copolymers have been successfully synthesized by an end‐capped Yamamoto reaction and further atom transfer radical polymerization. The copolymer film on a glass substrate could be selectively photo‐crosslinked using 365 nm UV radiation and a mask with a standard photopattern process. Elaborate and complex pixel structures are easily obtained, which may be applied to fabricate pixelated matrix displays and large area displays in the future. Furthermore, the crosslinked PF‐b‐PCEA film shows better stability under thermal stress and UV irradiation than the homopolymer, which indicates that the block copolymers could have a longer lifetime and stability when they are used in OLED fabrication. The optical properties and conversion of the photo‐responsive group are also investigated by various methods and confirm the photo‐responsive property. The corresponding results show that many other types of photo‐crosslinkable light‐emitting materials can be conveniently and efficiently obtained by this method.“Fudan university badge” feature obtained by photolithography.magnified image“Fudan university badge” feature obtained by photolithography.

Osmium‐ and Ruthenium‐Based Phosphorescent Materials: Design, Photophysics, and Utilization in OLED Fabrication

AbstractOsmium(II) complexes possessing β‐diketonate, quinolinate, diimine, and C‐linked pyridyl azolate chelates reveal interesting structural and photophysical properties. Spectroscopic and dynamic measurements, in combination with theoretical analyses, have provided an important understanding of the electronically excited state properties of these complexes, such as the energy gap and nature of the lower lying states, rate for intersystem crossing, and the efficiency of corresponding radiative decay and nonradiative deactivation processes. This review also reports on the synthetic processes that lead to the neutral OsII and RuII complexes that possess two trans‐substituted phosphane donor ligands together with two anti‐parallel, aligned azolate chromophores. Considerable efforts have been made to focus on utilizing these emitting materials as phosphorescent dopants for practical PLED and OLED fabrication. Consequently, the interplay between these emitting materials and device configurations is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)

Spin-coated conductive polymer film resistivity measurement using the TLM method

Organic conductors such as PEDOT:PSS are commonly used for the fabrication of OLEDs or OTFT transistors. Conductivity measurement is mandatory to improve both material composition and process parameters, and to allow device and circuit modeling. Film deposition using spin-coating on circular TLM electrode structures is a straightforward method for extracting both the film resistance and the contact resistivity, providing an accurate model is used. A practical measurement procedure is described in detail and applied to the measurement of PEDOT:PSS solutions.

Ultrathin sol–gel titanium oxide hole injection layer in OLEDs

In this work, we report an application of sol–gel process in the fabrication of OLEDs. The hole injection efficiency was improved tremendously by inserting an ultrathin sol–gel titanium oxide buffer layer between the ITO anode and hole transport layer. The turn-on voltage of the device with the buffer layer was lowered from 10 V to 3.1, and the operating voltage (at 200 cd/m 2) from 13.8 to 6.4 V, compared with the device without such a buffer layer. These devices demonstrated a maximum luminance of ∼40,000 cd/m 2. The mechanisms behind the enhanced performance were discussed.

(C(wedge)N(wedge)N)Pt(C identical to C)nR] (HC(wedge)N(wedge)N = 6-aryl-2,2'-bipyridine, n = 1-4, R = aryl, SiMe3) as a new class of light-emitting materials and their applications in electrophosphorescent devices.

Tridentate cyclometalated platinum(II) complexes bearing sigma-alkynyl ligands exhibit tunable photoluminescence and enhanced stability during vacuum deposition; OLEDs based on these materials display orange to red electrophosphorescence with low turn-on voltages (approximately 4 V), maximum luminance approaching 10,000 cd m-2 and efficiency up to 4.2 cd A-1.