Fast Thermal Evaporation in Purification of 1,4‐Di(pyren‐1‐ly)benzene

Abstract

This work presents a fast purification system that involves a vertical quartz tube and vacuum sublimation for separation without dilution. This system produced re-crystallized 1,4-di(pyren-1-yl)benzene (DPB) in a few hours following the synthesis of pyrene derivatives with a mole yield ratio of 1,4-di(pyrene-1yl)benzene to 1-phenylpyrene (1PP) of 5:1. Differential scanning calorimetry (DSC) and X-ray diffractometry (XRD) were utilized to identify the products. Finally, the lifetimes of pyrene derivatives DPB and 1PP were determined by exponential regression to be 10.0 ± 0.14 and 3.3 ± 0.15 ns, respectively. From the lifetime measurements, the purity of the photo-responsive materials could be easily determined. To prevent red-shift of electro-luminescence (EL) spectra by the energy transfer mechanism, it has acquired to elect transfer layers for pure electroluminescence. A co-catalytic reaction reduced the amount of impurities and eliminated the need for the use of a solvent in the purification step. CHEMICAL SOCIETYFig. 3. (a) Scheme of photon-path of lifetime measurement, (b) Exponential fitting curve for lifetime t value of purified sample evaporated at 350 o C, mixing material (DPB: 1PP = 1:1) at 350 o C and the product evaporated at 330 o C were 10.0 ± 0.14, 3.3 ± 0.15 and 3.3 ± 0.08 ns, respectively.

Pure white OLED based on an organic small molecule: 2,6-Di(1H-benzo[d]imidazol-2-yl)pyridine

“…However, rare pure white OLEDs based on organic small molecules were reported [19]. Organic compounds used as white emissive materials in OLED possess their advantage: purified easily via thermal sublimated [20], and very stable properties in the atmosphere. Here, we obtained a pure white OLED based on an organic small molecule DBIP due to combining the emissions of DBIP and the low-lying singlet excitons, as was leaded to only a tri-layer structure's device being structurally simpler than the white OLEDs achieved by combining the emissions of red, green, and blue [21][22][23].…”