Characterization and Improvement of Polymer Solution Light-Emitting Devices
Abstract
Our original objective was the understanding of polymer solution light-emitting devices (SLED), from device mechanism to materials. After a two-year intense research on SLEDs, we have expanded our project to other areas, from SLEDs, to phosphorescent PLEDs, and high performance photovoltaic devices. It is realized that our SLED has a similar mechanism as the ECL process. The electrogenerated chemiluminescence (ECL) process usually involves at least two species (or two reactions). One reaction is the oxidation process in which a species is oxidized near the anode to form a radical cation and the other species is reduced near the cathode to form a radical anion. The radical species with lower molecular weight will move to the counter-electrode. When the radical anions and radical cations encounter within the charge hopping distance, charge transfer will occur. The electron transition is from the high-energy excited state (Eex) to the low-energy state. In the case of poly 9,9-BIS(3,6-DIOXAHEPTYL)-FLUORENE-2,7-DIYL (BDOH-PF) and 1,2-dichlorobenzene (DCB), Eex(BDOH-PF < Eex(DCB) and the radical cation of DCB will transfer its positive charge to the radical anions of BDOH-PF (actually an electron hops from the radical anion to the DCB radical cation) to form the excited state of BDOH-PF and blue light emission will take place when the excited state decays to its ground state.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 03, 2003
- Accession Number
- ADA413397
Entities
People
- Fred Wudl
- Yang Yang
Organizations
- University of California, Los Angeles