Blue Host Materials Research Articles

High-efficiency deep blue host for organic light-emitting devices

High-efficiency deep blue organic light-emitting devices have been fabricated using asymmetrically substituted 9-(α-naphthyl)-10-(β-naphthyl)-anthracene as blue host material and diphenyl-[4-(2-[1,1′;4′,1″]terphenyl-4-yl-vinyl)-phenyl]amine as dopant emitter. With an optimized device structure and doping concentration, the deep blue electroluminescent (EL) device achieved an EL efficiency of 4.9cd∕A and an external quantum efficiency of 4.4% at a current density of 20mA∕cm2 at saturated blue Commission Internationale de l’Eclairage coordinates of (0.15, 0.13). The deep blue device also has a current efficiency which is invariable with driving conditions ranging from 10to100mA∕cm2.

Kinetic Aspects of Ion Exchange in KhFek[Fe(CN)6]l·mH2O Compounds: A Combined Electrical and Mass Transfer Functions Approach

The present paper quantifies and develops the kinetic aspects involved in the mechanism of interplay between electron and ions presented elsewhere(1) for K(h)Fe(k)[Fe(CN)(6)](l)*mH(2)O (Prussian Blue) host materials. Accordingly, there are three different electrochemical processes involved in the PB host materials: H(3)O(+), K(+), and H(+) insertion/extraction mechanisms which here were fully kinetically studied by means of the use of combined electronic and mass transfer functions as a tool to separate all the processes. The use of combined electronic and mass transfer functions was very important to validate and confirm the proposed mechanism. This mechanism allows the electrochemical and chemical processes involved in the K(h)Fe(k)[Fe(CN)(6)](l)*mH(2)O host and Prussian Blue derivatives to be understood. In addition, a formalism was also developed to consider superficial oxygen reduction. From the analysis of the kinetic processes involved in the model, it was possible to demonstrate that the processes associated with K(+) and H(+) exchanges are reversible whereas the H(3)O(+) insertion process was shown not to present a reversible pattern. This irreversible pattern is very peculiar and was shown to be related to the catalytic proton reduction reaction. Furthermore, from the model, it was possible to calculate the number density of available sites for each intercalation/deintercalation processes and infer that they are very similar for K(+) and H(+). Hence, the high prominence of the K(+) exchange observed in the voltammetric responses has a kinetic origin and is not related to the amount of sites available for intercalation/deintercalation of the ions.

Efficient blue organic light-emitting devices based on novel anthracence derivatives with pronounced thermal stability and excellent film-forming property

A series of anthracene based blue host materials was synthesized and characterized with respect to their chemical, luminescence, film-forming and thermal properties. The anthracene derivatives are strongly blue fluorescent ( λ f = 435–445 nm) with high fluorescence quantum yields ( Φ f = 0.71–0.85). All of these compounds have excellent film-forming properties and thermal properties. Organic light-emitting devices (OLEDs) fabricated using these three compounds as blue host emitter and using 0.5-wt% tetra ( t-butyl) perylene (TBPe) dopant in the emitting layer exhibit good light emitting performance with bright blue emission.

Experimental and Theoretical Demonstration on the Transport Properties of Fused Ring Host Materials for Organic Light-Emitting Diodes

The charge transport properties of three tertiary-butyl (t-Bu) substituted anthracene derivatives (ADN), critical blue host materials for organic light-emitting diodes (OLEDs), have been investigated experimentally and computationally. From time-of-flight (TOF) measurements, all ADN compounds exhibit ambipolar characters. The hole and electron mobilities are in the range (1–5)×10-7 cm2 V-1 s-1 under an external applied field of about 1 MV cm-1. Un-substituted ADN has the highest carrier mobilities while heavily t-Bu substituted ADN has the least. The electron and hole conducting properties of are consistent with ab initio calculation, which indicates that the frontier orbitals are localized mainly on the anthracene moiety. t-Bu substitutions in ADN increase the hopping path lengths among the molecules and hence reduce the electron and hole mobilities. The results demonstrate that t-Bu substitution is an effective means of engineering the conductivity of organic charge transporter for OLED applications.

P-131: Novel Deep Blue Dopants for Organic Light Emitting Devices

New deep blue dopants based on a “linked” stilbene moiety have been designed and synthesized. When doped in the stable blue host material, 2-methyl-9,10-di(2-naphthyl)anthracene (MADN) with a hole blocking layer, the SK-1 doped blue device achieved a luminance efficiency of 4.7 cd/A with corresponding CIE(inx, y) of (0.145, 0.134) at 20 mA/cm(su2) and an external quantum efficiency of 4.1%.

P‐115: Efficient Blue Organic Electroluminescent Devices Based on a Stable Blue Host Material

AbstractWe have successfully synthesized a new blue host material, 2‐methyl‐9,10‐di(2‐napthyl)anthracene (MADN) which is highly stable in thin‐film morphology comparing to the archetypical 9,10‐di(2‐napthyl)anthracene (ADN). When doped with 2,5,8,11‐tetra(t‐butyl)perylene (TBP) as blue emitter in organic light emitting device (OLED), MADN shows an improved EL efficiency of 4.4 cd/A and 2.2 lm/W at 20 mA/cm2 and 6.3 V with a CIEx, y coordinate of (0.14, 0.20). The blue device is stable with an extrapolated t1/2 ∼5000 h at an initial brightness of 880 cd/m2.

Synthesis of t-butylated diphenylanthracene derivatives as blue host materials for OLED applications

This paper describes the cost-effective synthesis and the photoluminescence of diphenylanthracene derivatives, which are found to be potential blue host materials for organic light emitting diode (OLED) technology.