Highly efficient and concentration-insensitive OLEDs based on alkyl sterically modified red homoleptic phenylphthalazine iridium complexes was written by Tao, Zheng-Yu;Pan, Ze-Hui;Wang, Ying-Jie;Fu, Tian-Ling;Xu, Hui-Hui;Zhang, Qian-Feng;Tong, Bi-Hai;Fung, Man-Keung;Tian, Yong-Pan. And the article was included in Dyes and Pigments in 2022.Safety of Dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile This article mentions the following:
Four red homoleptic iridium (III) complexes (Ir1-Ir4) with steric phenylphthalazine ligands have been synthesized. Single X-ray structural anal. shows that the steric hindrance groups can prevent mol. aggregation. All complexes exhibited red emission with peaks between 614 and 629 nm in CH2Cl2 and photoluminescence quantum yields (QYs) of 44%-86% in doped films. They were concentration-insensitive, their QYs in neat powder and air atm. can reach a maximum of 15%. These complexes exhibited excellent thermal stability with Td higher than 416 °C. The OLEDs based on these complexes showed good performances at 10 wt% high doping concentration Especially, the device based on Ir1 gave a peak current efficiency and external quantum efficiency (EQE) of 25.0 cd A-1 and 24.2% with mild efficiency roll-off, which is the most efficient OLED based on phthalazine iridium complexes. The maximum EQEs of non-doped devices are between 4.0% and 5.6%, which are considerably high, compared with the reported efficiency of iridium complexes based red-emitting non-doped devices. These studies show that increasing the d. of the rigid steric groups of iridium complexes is very effective to achieve high efficiency and low concentration sensitive red phosphorescent devices. In the experiment, the researchers used many compounds, for example, Dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (cas: 105598-27-4Safety of Dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile).
Dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (cas: 105598-27-4) belongs to quinoxaline derivatives. Quinoxalines have received a significant amount of attention due to their potential use in fighting various pathophysiological conditions like epilepsy, Parkinson’s, and Alzheimer’s diseases. Quinoxaline and its analogues may also be formed by reduction of amino acids substituted 1,5-difluoro-2,4-dinitrobenzene (DFDNB),One study used 2-iodoxybenzoic acid (IBX) as a catalyst in the reaction of benzil with 1,2-diaminobenzene.Safety of Dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile
Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider