Material degradation of liquid organic semiconductors analyzed by nuclear magnetic resonance spectroscopy

作者：Fukushima Tatsuya; Yamamoto Junichi; Fukuchi Masashi; Hirata Shuzo; Jung Heo Hyo; Hirata Osamu; Shibano Yuki; Adachi Chihaya; Kaji Hironori^*

来源：AIP Advances, 2015, 5(8): 087124.

DOI：10.1063/1.4928515

Liquid organic light-emitting diodes (liquid OLEDs) are unique devices consisting only of liquid organic semiconductors in the active layer, and the device performances have been investigated recently. However, the device degradation, especially, the origin has been unknown. In this study, we show that material degradation occurs in liquid OLEDs, whose active layer is composed of carbazole with an ethylene glycol chain. Nuclear magnetic resonance (NMR) experiments clearly exhibit that the dimerization reaction of carbazole moiety occurs in the liquid OLEDs during driving the devices. In contrast, cleavages of the ethylene glycol chain are not detected within experimental error. The dimerization reaction is considered to be related to the device degradation.

• 出版日期2015-8