Highly Efficient Electron-Transporting/Injecting and Thermally Stable Naphthyridines for Organic Electrophosphorescent Devices - Xiao, Lixin; Xing, Xing; Chen, Zhijian; Qu, Bo; Lan, Hsinglin; Qihuang Gong; Kido, Junji (ADVANCED FUNCTIONAL MATERIALS, 2013)