摘要:
Two novel azatetracenes: 5,7,8,9,10,12-hexaphenyl-2-azatetracene (2) and 1,4,6,11-tetraphenyl-2,3-diazatetracene (3), were synthesized and characterized. Comparing to Rubrene, 2 and 3 show blue-shifted absorptions. Interestingly, 2 displays stronger emission than rubrene in CH2Cl2, while the fluorescence of 3 is almost quenched. The electrochemical studies suggested that inserting sp(2) N atoms into the backbone of tetracene could decrease both HOMO and LUMO orbital energies and more sp(2) N atoms would result in lower HOMO orbital energy level. Since 2 has stronger fluorescence than rubrene, organic light emitting devices with 2 as emitters have been fabricated and the as-fabricated devices show a maximum current efficiency as high as 6.6 cd A(-1). Our results indicated that the number of sp(2) N atoms in the backbone of parent oligoacenes did have strong effect on the properties of as-resulted azaoligoacenes and this research could provide some guides to design and synthesize novel larger azaacenes. (C) 2014 Elsevier Ltd. All rights reserved.