[6p-A203-1~19] 12.4 Organic light-emitting devices and organic transistors

[6p-A203-16] Applications of lithium-bipyridilphenolate complexes with terminal pyridines substituted at different positions to organic light-emitting devices.

〇Satoru Ohisa^1,2,3, Taichiro Karasawa¹, Yuichiro Watanabe¹, Tatsuya Ohsawa¹, Yong-Jin Pu^1,2,3, Hisahiro Sasabe^1,2,3, Junji Kido^1,2,3 (1.Yamagata Univ., 2.ROEL, Yamagata Univ., 3.FROM, Yamagata Univ.)

Keywords:organic light-emitting devices, electron injection, lithium complex

Lithium-bipyridylphenolate complexes with terminal pyridines substituted at the 2-, 3- and 4- positions (Li2BPP, Li3BPP, Li4BPP) were applied to the electron injection layer in organic light-emitting devices. The dependence of the driving voltage on the film thickness was specifically lower in Li2BPP-based devices compared to the others-based devices. From density functional theory calculations, the terminal pyridine of Li2BPP chelated with lithium and made a planar bipyridine structure. This planar structure resulted in large π–π interaction, and Li2BPP showed high crystallinity. We considered that the film thickness dependence which is specifically low is resulted from this high crystallinity.