Using an environmentally stable metal as the cathode in a polymer light-emitting diode (PLED) is an essential requirement for its practical application. We present the preparation of a water/alcohol soluble copoly(p-phenylene) (P1) containing pendant azacrown ether and ethylene glycol ether groups as a highly efficient electron injection layer (EIL) for PLEDs, allowing the use of environmentally stable aluminum as the cathode. Multilayer PLEDs [ITO/PEDOT:PSS/PF-Green-B/EIL/Al] using P1 as EIL exhibit significantly enhanced device performance, particularly in the presence of K 2CO3 or Cs2CO3. The maximum luminous power efficiency and maximum luminance of the device with Cs2CO 3-doped P1 as EIL were enhanced to 9.16 lm W-1 and 17050 cd m-2, respectively, compared with those without EIL (0.16 lm W -1, 890 cd m-2). The turn-on voltage was also significantly reduced from 5.7 V to 3.7 V simultaneously. The performance enhancement has been attributed to improved electron injection which has been confirmed by the rise in open-circuit voltage (Voc) obtained from photovoltaic measurements. The incorporation of such an electron injection layer significantly enhances device performance for PLEDs with an environmentally stable metal as the cathode.
All Science Journal Classification (ASJC) codes
- Physical and Theoretical Chemistry
- Organic Chemistry