Highly Efficient Carbazole‐π‐Dimesitylborane Bipolar Fluorophores for Nondoped Blue Organic Light‐Emitting Diodes

Abstract

Highly efficient blue organic light-emitting diodes (OLEDs) are necessary for high-resolution full-color displays and solid-state lighting applications.[1] The dopant-host system is often adopted to improve OLED performance. However, electroluminescence (EL) properties, including color purity, are extremely sensitive to the dopant concentration, [2] which is usually less than 2 wt % with a AE0.5 wt % variation. Precise control of the dopant concentration using co-evaporation methods is not an easy task. The development of highperformance blue-light-emitting materials suitable for nondoped OLEDs is one method of circumventing such fabrication problems. With many literature examples, nondoped-type

Strategies to Design Bipolar Small Molecules for OLEDs: Donor‐Acceptor Structure and Non‐Donor‐Acceptor Structure

“…Lin et al addressed this issue by combining carbazole and dimesitylborane into a π -conjugation system. [ 14 ] Compared to other amino-donors, carbazoles are useful in generating shortwavelength absorption or emission as they are weaker π -donors than amines. Various π -conjugation bridges were utilized to modulate the photophysical properties of the molecules.…”

Organic Ambipolar Conjugated Molecules for Electronics: Synthesis and Structure–Property Relationships

“…[11] confinement of the light-emitting materials and the ideal alignment of HOMO and LUMO energy levels in the devices. [11] Similarly, an unprecedented blue-light emitting spiro-configured ambipolar molecule 5, [12] equipped with diphenylamino groups as electron donors and phenylbenzimidazole groups as electron acceptors, exhibits a combination of the physical properties originating from its donor (D) and acceptor (A) groups (Figure 2), which is incorporated into an efficient single-layer OLED device exhibiting blue-emission CIE coordinates of (0.15, 0.14), a turn-on potential of 4 V, a maximum brightness of 2 800 cd Á m À2 at 830 mA Á cm À2 and a maximum quantum efficiency of 0.53%. [13] Integrating electron-transport (ET) and hole-transport (HT) segments into molecular materials can effectively improve the OLED performance.…”

New V-shaped push-pull systems based upon 4,5-di(hetero)aryl substituted pyrimidines: their synthesis and application for the detection of nitroaromatic explosives

“…4,5-Bis[5-bromo(thien-2-yl)]pyrimidine (4) was prepared according to the earlier reported method. 47 The solvents (1,4-dioxane and H 2 O) for the microwave-assisted Suzuki cross-coupling reaction were degassed by bubbling argon for 1 h. 1 H and 13 C NMR spectra were recorded on a AVANCE-500 instruments using Me 4 Si as an internal standard. Elemental analysis was carried on a Eurovector EA 3000 automated analyzer.…”

“…Thanks to the presence of highly delocalized π-electronic systems, these molecules have found wide applications in organic light-emitting diodes (OLEDs), nonlinear optics, dye-sensitized solar cells and field-effect transistors (FETs). [13][14][15][16][17][18][19][20][21][22][23][24][25][26] Furthermore, triphenylamine and carbazolebased compounds are used successfully as sensors for the detection of nitroaromatic explosives. [27][28][29][30][31] Oligothiophenes and their derivatives have also been employed successfully as sensing elements for detection of explosives.…”