With the aim of enhancing the electron injection of a polymer light-emitting diode (PLED), a supramolecular insulating nanolayer that reacts with the cathode (Ag) was inserted between the bottom cathode and the emitting material. The PLED threshold voltage (for 1 cd/m2) was found to decrease from 5.6 to 4.2 V as a result of the introduction of the nanolayer. Synchrotron radiation photoelectron spectroscopy results show that inserting the supramolecular insulating nanolayer results in a decrease in the work function of about 0.7 eV. This reduction lowers the electron injection barrier and produces an increase in the luminance.
Bibliographical noteFunding Information:
The authors thank the Center for Nanostructural Materials Technology under the 21st Century Frontier R&D Programs (05K1501-01010), the National Research Laboratory Program of the Ministry of Science and Technology of Korea, and the BK21 Program of the Ministry of Education of Korea for their financial support and the Pohang Accelerator Laboratory for providing the 4B1 beam line used in this study.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)