A stable red emission in polymer light-emitting diodes based on phenothiazine derivative - Cao, Huayu; Chen, Zhijian; Liu, Yingliang; Li, Jianghui; Cao, Shaokui; Xiao, Lixin; Xu, Shengang; Qihuang Gong (LIGHT-EMITTING DIODE MATERIALS AND DEVICES II, 2008)