A blue polymer light emitting diode was prepared by inserting an electron transport layer between cathode and poly (N-vinylene carbazole) (PVK) doped by ladder poly(para-phenylene) (LPPP) layer. In comparison with the single layer LPPP device, the brightness of the device is improved by about one order of magnitude. An explanation based on energy diagram of the devices is presented.
Xiaohui, Y., Yanbing, H., Zhenjia, W., Xiaohong, C., Zheng, X., & Xurong, X. (2000). Blue polymer light emitting diode based on ladder poly(para-phenylene). Thin Solid Films, 363(1), 211–213. https://doi.org/10.1016/S0040-6090(99)01040-8